/* * Infrastructure for profiling code inserted by 'gcc -pg'. * * Copyright (C) 2007-2008 Steven Rostedt * Copyright (C) 2004-2008 Ingo Molnar * * Originally ported from the -rt patch by: * Copyright (C) 2007 Arnaldo Carvalho de Melo * * Based on code in the latency_tracer, that is: * * Copyright (C) 2004-2006 Ingo Molnar * Copyright (C) 2004 Nadia Yvette Chambers */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "trace_output.h" #include "trace_stat.h" #define FTRACE_WARN_ON(cond) \ ({ \ int ___r = cond; \ if (WARN_ON(___r)) \ ftrace_kill(); \ ___r; \ }) #define FTRACE_WARN_ON_ONCE(cond) \ ({ \ int ___r = cond; \ if (WARN_ON_ONCE(___r)) \ ftrace_kill(); \ ___r; \ }) /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) #define FTRACE_HASH_DEFAULT_BITS 10 #define FTRACE_HASH_MAX_BITS 12 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL) #ifdef CONFIG_DYNAMIC_FTRACE #define INIT_OPS_HASH(opsname) \ .func_hash = &opsname.local_hash, \ .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), #define ASSIGN_OPS_HASH(opsname, val) \ .func_hash = val, \ .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), #else #define INIT_OPS_HASH(opsname) #define ASSIGN_OPS_HASH(opsname, val) #endif static struct ftrace_ops ftrace_list_end __read_mostly = { .func = ftrace_stub, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB, INIT_OPS_HASH(ftrace_list_end) }; /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; static int last_ftrace_enabled; /* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; /* What to set function_trace_op to */ static struct ftrace_ops *set_function_trace_op; /* List for set_ftrace_pid's pids. */ LIST_HEAD(ftrace_pids); struct ftrace_pid { struct list_head list; struct pid *pid; }; static bool ftrace_pids_enabled(void) { return !list_empty(&ftrace_pids); } static void ftrace_update_trampoline(struct ftrace_ops *ops); /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. */ static int ftrace_disabled __read_mostly; static DEFINE_MUTEX(ftrace_lock); static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end; static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; static struct ftrace_ops global_ops; static struct ftrace_ops control_ops; static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs); #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs); #else /* See comment below, where ftrace_ops_list_func is defined */ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip); #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops) #endif /* * Traverse the ftrace_global_list, invoking all entries. The reason that we * can use rcu_dereference_raw_notrace() is that elements removed from this list * are simply leaked, so there is no need to interact with a grace-period * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle * concurrent insertions into the ftrace_global_list. * * Silly Alpha and silly pointer-speculation compiler optimizations! */ #define do_for_each_ftrace_op(op, list) \ op = rcu_dereference_raw_notrace(list); \ do /* * Optimized for just a single item in the list (as that is the normal case). */ #define while_for_each_ftrace_op(op) \ while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \ unlikely((op) != &ftrace_list_end)) static inline void ftrace_ops_init(struct ftrace_ops *ops) { #ifdef CONFIG_DYNAMIC_FTRACE if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) { mutex_init(&ops->local_hash.regex_lock); ops->func_hash = &ops->local_hash; ops->flags |= FTRACE_OPS_FL_INITIALIZED; } #endif } /** * ftrace_nr_registered_ops - return number of ops registered * * Returns the number of ftrace_ops registered and tracing functions */ int ftrace_nr_registered_ops(void) { struct ftrace_ops *ops; int cnt = 0; mutex_lock(&ftrace_lock); for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) cnt++; mutex_unlock(&ftrace_lock); return cnt; } static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { if (!test_tsk_trace_trace(current)) return; op->saved_func(ip, parent_ip, op, regs); } /** * clear_ftrace_function - reset the ftrace function * * This NULLs the ftrace function and in essence stops * tracing. There may be lag */ void clear_ftrace_function(void) { ftrace_trace_function = ftrace_stub; } static void control_ops_disable_all(struct ftrace_ops *ops) { int cpu; for_each_possible_cpu(cpu) *per_cpu_ptr(ops->disabled, cpu) = 1; } static int control_ops_alloc(struct ftrace_ops *ops) { int __percpu *disabled; disabled = alloc_percpu(int); if (!disabled) return -ENOMEM; ops->disabled = disabled; control_ops_disable_all(ops); return 0; } static void ftrace_sync(struct work_struct *work) { /* * This function is just a stub to implement a hard force * of synchronize_sched(). This requires synchronizing * tasks even in userspace and idle. * * Yes, function tracing is rude. */ } static void ftrace_sync_ipi(void *data) { /* Probably not needed, but do it anyway */ smp_rmb(); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static void update_function_graph_func(void); /* Both enabled by default (can be cleared by function_graph tracer flags */ static bool fgraph_sleep_time = true; static bool fgraph_graph_time = true; #else static inline void update_function_graph_func(void) { } #endif static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops) { /* * If this is a dynamic ops or we force list func, * then it needs to call the list anyway. */ if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC) return ftrace_ops_list_func; return ftrace_ops_get_func(ops); } static void update_ftrace_function(void) { ftrace_func_t func; /* * Prepare the ftrace_ops that the arch callback will use. * If there's only one ftrace_ops registered, the ftrace_ops_list * will point to the ops we want. */ set_function_trace_op = ftrace_ops_list; /* If there's no ftrace_ops registered, just call the stub function */ if (ftrace_ops_list == &ftrace_list_end) { func = ftrace_stub; /* * If we are at the end of the list and this ops is * recursion safe and not dynamic and the arch supports passing ops, * then have the mcount trampoline call the function directly. */ } else if (ftrace_ops_list->next == &ftrace_list_end) { func = ftrace_ops_get_list_func(ftrace_ops_list); } else { /* Just use the default ftrace_ops */ set_function_trace_op = &ftrace_list_end; func = ftrace_ops_list_func; } update_function_graph_func(); /* If there's no change, then do nothing more here */ if (ftrace_trace_function == func) return; /* * If we are using the list function, it doesn't care * about the function_trace_ops. */ if (func == ftrace_ops_list_func) { ftrace_trace_function = func; /* * Don't even bother setting function_trace_ops, * it would be racy to do so anyway. */ return; } #ifndef CONFIG_DYNAMIC_FTRACE /* * For static tracing, we need to be a bit more careful. * The function change takes affect immediately. Thus, * we need to coorditate the setting of the function_trace_ops * with the setting of the ftrace_trace_function. * * Set the function to the list ops, which will call the * function we want, albeit indirectly, but it handles the * ftrace_ops and doesn't depend on function_trace_op. */ ftrace_trace_function = ftrace_ops_list_func; /* * Make sure all CPUs see this. Yes this is slow, but static * tracing is slow and nasty to have enabled. */ schedule_on_each_cpu(ftrace_sync); /* Now all cpus are using the list ops. */ function_trace_op = set_function_trace_op; /* Make sure the function_trace_op is visible on all CPUs */ smp_wmb(); /* Nasty way to force a rmb on all cpus */ smp_call_function(ftrace_sync_ipi, NULL, 1); /* OK, we are all set to update the ftrace_trace_function now! */ #endif /* !CONFIG_DYNAMIC_FTRACE */ ftrace_trace_function = func; } int using_ftrace_ops_list_func(void) { return ftrace_trace_function == ftrace_ops_list_func; } static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { ops->next = *list; /* * We are entering ops into the list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees * the ops pointer included into the list. */ rcu_assign_pointer(*list, ops); } static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { struct ftrace_ops **p; /* * If we are removing the last function, then simply point * to the ftrace_stub. */ if (*list == ops && ops->next == &ftrace_list_end) { *list = &ftrace_list_end; return 0; } for (p = list; *p != &ftrace_list_end; p = &(*p)->next) if (*p == ops) break; if (*p != ops) return -1; *p = (*p)->next; return 0; } static void add_ftrace_list_ops(struct ftrace_ops **list, struct ftrace_ops *main_ops, struct ftrace_ops *ops) { int first = *list == &ftrace_list_end; add_ftrace_ops(list, ops); if (first) add_ftrace_ops(&ftrace_ops_list, main_ops); } static int remove_ftrace_list_ops(struct ftrace_ops **list, struct ftrace_ops *main_ops, struct ftrace_ops *ops) { int ret = remove_ftrace_ops(list, ops); if (!ret && *list == &ftrace_list_end) ret = remove_ftrace_ops(&ftrace_ops_list, main_ops); return ret; } static void ftrace_update_trampoline(struct ftrace_ops *ops); static int __register_ftrace_function(struct ftrace_ops *ops) { if (ops->flags & FTRACE_OPS_FL_DELETED) return -EINVAL; if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY; #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * If the ftrace_ops specifies SAVE_REGS, then it only can be used * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set. * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant. */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS && !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)) return -EINVAL; if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED) ops->flags |= FTRACE_OPS_FL_SAVE_REGS; #endif if (!core_kernel_data((unsigned long)ops)) ops->flags |= FTRACE_OPS_FL_DYNAMIC; if (ops->flags & FTRACE_OPS_FL_CONTROL) { if (control_ops_alloc(ops)) return -ENOMEM; add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops); /* The control_ops needs the trampoline update */ ops = &control_ops; } else add_ftrace_ops(&ftrace_ops_list, ops); /* Always save the function, and reset at unregistering */ ops->saved_func = ops->func; if (ops->flags & FTRACE_OPS_FL_PID && ftrace_pids_enabled()) ops->func = ftrace_pid_func; ftrace_update_trampoline(ops); if (ftrace_enabled) update_ftrace_function(); return 0; } static int __unregister_ftrace_function(struct ftrace_ops *ops) { int ret; if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) return -EBUSY; if (ops->flags & FTRACE_OPS_FL_CONTROL) { ret = remove_ftrace_list_ops(&ftrace_control_list, &control_ops, ops); } else ret = remove_ftrace_ops(&ftrace_ops_list, ops); if (ret < 0) return ret; if (ftrace_enabled) update_ftrace_function(); ops->func = ops->saved_func; return 0; } static void ftrace_update_pid_func(void) { bool enabled = ftrace_pids_enabled(); struct ftrace_ops *op; /* Only do something if we are tracing something */ if (ftrace_trace_function == ftrace_stub) return; do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->flags & FTRACE_OPS_FL_PID) { op->func = enabled ? ftrace_pid_func : op->saved_func; ftrace_update_trampoline(op); } } while_for_each_ftrace_op(op); update_ftrace_function(); } #ifdef CONFIG_FUNCTION_PROFILER struct ftrace_profile { struct hlist_node node; unsigned long ip; unsigned long counter; #ifdef CONFIG_FUNCTION_GRAPH_TRACER unsigned long long time; unsigned long long time_squared; #endif }; struct ftrace_profile_page { struct ftrace_profile_page *next; unsigned long index; struct ftrace_profile records[]; }; struct ftrace_profile_stat { atomic_t disabled; struct hlist_head *hash; struct ftrace_profile_page *pages; struct ftrace_profile_page *start; struct tracer_stat stat; }; #define PROFILE_RECORDS_SIZE \ (PAGE_SIZE - offsetof(struct ftrace_profile_page, records)) #define PROFILES_PER_PAGE \ (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile)) static int ftrace_profile_enabled __read_mostly; /* ftrace_profile_lock - synchronize the enable and disable of the profiler */ static DEFINE_MUTEX(ftrace_profile_lock); static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats); #define FTRACE_PROFILE_HASH_BITS 10 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS) static void * function_stat_next(void *v, int idx) { struct ftrace_profile *rec = v; struct ftrace_profile_page *pg; pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); again: if (idx != 0) rec++; if ((void *)rec >= (void *)&pg->records[pg->index]) { pg = pg->next; if (!pg) return NULL; rec = &pg->records[0]; if (!rec->counter) goto again; } return rec; } static void *function_stat_start(struct tracer_stat *trace) { struct ftrace_profile_stat *stat = container_of(trace, struct ftrace_profile_stat, stat); if (!stat || !stat->start) return NULL; return function_stat_next(&stat->start->records[0], 0); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* function graph compares on total time */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->time < b->time) return -1; if (a->time > b->time) return 1; else return 0; } #else /* not function graph compares against hits */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->counter < b->counter) return -1; if (a->counter > b->counter) return 1; else return 0; } #endif static int function_stat_headers(struct seq_file *m) { #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " Function " "Hit Time Avg s^2\n" " -------- " "--- ---- --- ---\n"); #else seq_puts(m, " Function Hit\n" " -------- ---\n"); #endif return 0; } static int function_stat_show(struct seq_file *m, void *v) { struct ftrace_profile *rec = v; char str[KSYM_SYMBOL_LEN]; int ret = 0; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static struct trace_seq s; unsigned long long avg; unsigned long long stddev; #endif mutex_lock(&ftrace_profile_lock); /* we raced with function_profile_reset() */ if (unlikely(rec->counter == 0)) { ret = -EBUSY; goto out; } #ifdef CONFIG_FUNCTION_GRAPH_TRACER avg = div64_ul(rec->time, rec->counter); if (tracing_thresh && (avg < tracing_thresh)) goto out; #endif kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); seq_printf(m, " %-30.30s %10lu", str, rec->counter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " "); /* Sample standard deviation (s^2) */ if (rec->counter <= 1) stddev = 0; else { /* * Apply Welford's method: * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) */ stddev = rec->counter * rec->time_squared - rec->time * rec->time; /* * Divide only 1000 for ns^2 -> us^2 conversion. * trace_print_graph_duration will divide 1000 again. */ stddev = div64_ul(stddev, rec->counter * (rec->counter - 1) * 1000); } trace_seq_init(&s); trace_print_graph_duration(rec->time, &s); trace_seq_puts(&s, " "); trace_print_graph_duration(avg, &s); trace_seq_puts(&s, " "); trace_print_graph_duration(stddev, &s); trace_print_seq(m, &s); #endif seq_putc(m, '\n'); out: mutex_unlock(&ftrace_profile_lock); return ret; } static void ftrace_profile_reset(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; pg = stat->pages = stat->start; while (pg) { memset(pg->records, 0, PROFILE_RECORDS_SIZE); pg->index = 0; pg = pg->next; } memset(stat->hash, 0, FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head)); } int ftrace_profile_pages_init(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; int functions; int pages; int i; /* If we already allocated, do nothing */ if (stat->pages) return 0; stat->pages = (void *)get_zeroed_page(GFP_KERNEL); if (!stat->pages) return -ENOMEM; #ifdef CONFIG_DYNAMIC_FTRACE functions = ftrace_update_tot_cnt; #else /* * We do not know the number of functions that exist because * dynamic tracing is what counts them. With past experience * we have around 20K functions. That should be more than enough. * It is highly unlikely we will execute every function in * the kernel. */ functions = 20000; #endif pg = stat->start = stat->pages; pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE); for (i = 1; i < pages; i++) { pg->next = (void *)get_zeroed_page(GFP_KERNEL); if (!pg->next) goto out_free; pg = pg->next; } return 0; out_free: pg = stat->start; while (pg) { unsigned long tmp = (unsigned long)pg; pg = pg->next; free_page(tmp); } stat->pages = NULL; stat->start = NULL; return -ENOMEM; } static int ftrace_profile_init_cpu(int cpu) { struct ftrace_profile_stat *stat; int size; stat = &per_cpu(ftrace_profile_stats, cpu); if (stat->hash) { /* If the profile is already created, simply reset it */ ftrace_profile_reset(stat); return 0; } /* * We are profiling all functions, but usually only a few thousand * functions are hit. We'll make a hash of 1024 items. */ size = FTRACE_PROFILE_HASH_SIZE; stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL); if (!stat->hash) return -ENOMEM; /* Preallocate the function profiling pages */ if (ftrace_profile_pages_init(stat) < 0) { kfree(stat->hash); stat->hash = NULL; return -ENOMEM; } return 0; } static int ftrace_profile_init(void) { int cpu; int ret = 0; for_each_possible_cpu(cpu) { ret = ftrace_profile_init_cpu(cpu); if (ret) break; } return ret; } /* interrupts must be disabled */ static struct ftrace_profile * ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec; struct hlist_head *hhd; unsigned long key; key = hash_long(ip, FTRACE_PROFILE_HASH_BITS); hhd = &stat->hash[key]; if (hlist_empty(hhd)) return NULL; hlist_for_each_entry_rcu_notrace(rec, hhd, node) { if (rec->ip == ip) return rec; } return NULL; } static void ftrace_add_profile(struct ftrace_profile_stat *stat, struct ftrace_profile *rec) { unsigned long key; key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS); hlist_add_head_rcu(&rec->node, &stat->hash[key]); } /* * The memory is already allocated, this simply finds a new record to use. */ static struct ftrace_profile * ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec = NULL; /* prevent recursion (from NMIs) */ if (atomic_inc_return(&stat->disabled) != 1) goto out; /* * Try to find the function again since an NMI * could have added it */ rec = ftrace_find_profiled_func(stat, ip); if (rec) goto out; if (stat->pages->index == PROFILES_PER_PAGE) { if (!stat->pages->next) goto out; stat->pages = stat->pages->next; } rec = &stat->pages->records[stat->pages->index++]; rec->ip = ip; ftrace_add_profile(stat, rec); out: atomic_dec(&stat->disabled); return rec; } static void function_profile_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct pt_regs *regs) { struct ftrace_profile_stat *stat; struct ftrace_profile *rec; unsigned long flags; if (!ftrace_profile_enabled) return; local_irq_save(flags); stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; rec = ftrace_find_profiled_func(stat, ip); if (!rec) { rec = ftrace_profile_alloc(stat, ip); if (!rec) goto out; } rec->counter++; out: local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int profile_graph_entry(struct ftrace_graph_ent *trace) { function_profile_call(trace->func, 0, NULL, NULL); return 1; } static void profile_graph_return(struct ftrace_graph_ret *trace) { struct ftrace_profile_stat *stat; unsigned long long calltime; struct ftrace_profile *rec; unsigned long flags; local_irq_save(flags); stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; /* If the calltime was zero'd ignore it */ if (!trace->calltime) goto out; calltime = trace->rettime - trace->calltime; if (!fgraph_graph_time) { int index; index = trace->depth; /* Append this call time to the parent time to subtract */ if (index) current->ret_stack[index - 1].subtime += calltime; if (current->ret_stack[index].subtime < calltime) calltime -= current->ret_stack[index].subtime; else calltime = 0; } rec = ftrace_find_profiled_func(stat, trace->func); if (rec) { rec->time += calltime; rec->time_squared += calltime * calltime; } out: local_irq_restore(flags); } static int register_ftrace_profiler(void) { return register_ftrace_graph(&profile_graph_return, &profile_graph_entry); } static void unregister_ftrace_profiler(void) { unregister_ftrace_graph(); } #else static struct ftrace_ops ftrace_profile_ops __read_mostly = { .func = function_profile_call, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, INIT_OPS_HASH(ftrace_profile_ops) }; static int register_ftrace_profiler(void) { return register_ftrace_function(&ftrace_profile_ops); } static void unregister_ftrace_profiler(void) { unregister_ftrace_function(&ftrace_profile_ops); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ static ssize_t ftrace_profile_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; val = !!val; mutex_lock(&ftrace_profile_lock); if (ftrace_profile_enabled ^ val) { if (val) { ret = ftrace_profile_init(); if (ret < 0) { cnt = ret; goto out; } ret = register_ftrace_profiler(); if (ret < 0) { cnt = ret; goto out; } ftrace_profile_enabled = 1; } else { ftrace_profile_enabled = 0; /* * unregister_ftrace_profiler calls stop_machine * so this acts like an synchronize_sched. */ unregister_ftrace_profiler(); } } out: mutex_unlock(&ftrace_profile_lock); *ppos += cnt; return cnt; } static ssize_t ftrace_profile_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; /* big enough to hold a number */ int r; r = sprintf(buf, "%u\n", ftrace_profile_enabled); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static const struct file_operations ftrace_profile_fops = { .open = tracing_open_generic, .read = ftrace_profile_read, .write = ftrace_profile_write, .llseek = default_llseek, }; /* used to initialize the real stat files */ static struct tracer_stat function_stats __initdata = { .name = "functions", .stat_start = function_stat_start, .stat_next = function_stat_next, .stat_cmp = function_stat_cmp, .stat_headers = function_stat_headers, .stat_show = function_stat_show }; static __init void ftrace_profile_tracefs(struct dentry *d_tracer) { struct ftrace_profile_stat *stat; struct dentry *entry; char *name; int ret; int cpu; for_each_possible_cpu(cpu) { stat = &per_cpu(ftrace_profile_stats, cpu); /* allocate enough for function name + cpu number */ name = kmalloc(32, GFP_KERNEL); if (!name) { /* * The files created are permanent, if something happens * we still do not free memory. */ WARN(1, "Could not allocate stat file for cpu %d\n", cpu); return; } stat->stat = function_stats; snprintf(name, 32, "function%d", cpu); stat->stat.name = name; ret = register_stat_tracer(&stat->stat); if (ret) { WARN(1, "Could not register function stat for cpu %d\n", cpu); kfree(name); return; } } entry = tracefs_create_file("function_profile_enabled", 0644, d_tracer, NULL, &ftrace_profile_fops); if (!entry) pr_warning("Could not create tracefs " "'function_profile_enabled' entry\n"); } #else /* CONFIG_FUNCTION_PROFILER */ static __init void ftrace_profile_tracefs(struct dentry *d_tracer) { } #endif /* CONFIG_FUNCTION_PROFILER */ static struct pid * const ftrace_swapper_pid = &init_struct_pid; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int ftrace_graph_active; #else # define ftrace_graph_active 0 #endif #ifdef CONFIG_DYNAMIC_FTRACE static struct ftrace_ops *removed_ops; /* * Set when doing a global update, like enabling all recs or disabling them. * It is not set when just updating a single ftrace_ops. */ static bool update_all_ops; #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly; struct ftrace_func_probe { struct hlist_node node; struct ftrace_probe_ops *ops; unsigned long flags; unsigned long ip; void *data; struct list_head free_list; }; struct ftrace_func_entry { struct hlist_node hlist; unsigned long ip; }; struct ftrace_hash { unsigned long size_bits; struct hlist_head *buckets; unsigned long count; struct rcu_head rcu; }; /* * We make these constant because no one should touch them, * but they are used as the default "empty hash", to avoid allocating * it all the time. These are in a read only section such that if * anyone does try to modify it, it will cause an exception. */ static const struct hlist_head empty_buckets[1]; static const struct ftrace_hash empty_hash = { .buckets = (struct hlist_head *)empty_buckets, }; #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) static struct ftrace_ops global_ops = { .func = ftrace_stub, .local_hash.notrace_hash = EMPTY_HASH, .local_hash.filter_hash = EMPTY_HASH, INIT_OPS_HASH(global_ops) .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; /* * This is used by __kernel_text_address() to return true if the * address is on a dynamically allocated trampoline that would * not return true for either core_kernel_text() or * is_module_text_address(). */ bool is_ftrace_trampoline(unsigned long addr) { struct ftrace_ops *op; bool ret = false; /* * Some of the ops may be dynamically allocated, * they are freed after a synchronize_sched(). */ preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { /* * This is to check for dynamically allocated trampolines. * Trampolines that are in kernel text will have * core_kernel_text() return true. */ if (op->trampoline && op->trampoline_size) if (addr >= op->trampoline && addr < op->trampoline + op->trampoline_size) { ret = true; goto out; } } while_for_each_ftrace_op(op); out: preempt_enable_notrace(); return ret; } struct ftrace_page { struct ftrace_page *next; struct dyn_ftrace *records; int index; int size; }; #define ENTRY_SIZE sizeof(struct dyn_ftrace) #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE) /* estimate from running different kernels */ #define NR_TO_INIT 10000 static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash) { return !hash || !hash->count; } static struct ftrace_func_entry * ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) { unsigned long key; struct ftrace_func_entry *entry; struct hlist_head *hhd; if (ftrace_hash_empty(hash)) return NULL; if (hash->size_bits > 0) key = hash_long(ip, hash->size_bits); else key = 0; hhd = &hash->buckets[key]; hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) { if (entry->ip == ip) return entry; } return NULL; } static void __add_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { struct hlist_head *hhd; unsigned long key; if (hash->size_bits) key = hash_long(entry->ip, hash->size_bits); else key = 0; hhd = &hash->buckets[key]; hlist_add_head(&entry->hlist, hhd); hash->count++; } static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) { struct ftrace_func_entry *entry; entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return -ENOMEM; entry->ip = ip; __add_hash_entry(hash, entry); return 0; } static void free_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { hlist_del(&entry->hlist); kfree(entry); hash->count--; } static void remove_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { hlist_del(&entry->hlist); hash->count--; } static void ftrace_hash_clear(struct ftrace_hash *hash) { struct hlist_head *hhd; struct hlist_node *tn; struct ftrace_func_entry *entry; int size = 1 << hash->size_bits; int i; if (!hash->count) return; for (i = 0; i < size; i++) { hhd = &hash->buckets[i]; hlist_for_each_entry_safe(entry, tn, hhd, hlist) free_hash_entry(hash, entry); } FTRACE_WARN_ON(hash->count); } static void free_ftrace_hash(struct ftrace_hash *hash) { if (!hash || hash == EMPTY_HASH) return; ftrace_hash_clear(hash); kfree(hash->buckets); kfree(hash); } static void __free_ftrace_hash_rcu(struct rcu_head *rcu) { struct ftrace_hash *hash; hash = container_of(rcu, struct ftrace_hash, rcu); free_ftrace_hash(hash); } static void free_ftrace_hash_rcu(struct ftrace_hash *hash) { if (!hash || hash == EMPTY_HASH) return; call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu); } void ftrace_free_filter(struct ftrace_ops *ops) { ftrace_ops_init(ops); free_ftrace_hash(ops->func_hash->filter_hash); free_ftrace_hash(ops->func_hash->notrace_hash); } static struct ftrace_hash *alloc_ftrace_hash(int size_bits) { struct ftrace_hash *hash; int size; hash = kzalloc(sizeof(*hash), GFP_KERNEL); if (!hash) return NULL; size = 1 << size_bits; hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL); if (!hash->buckets) { kfree(hash); return NULL; } hash->size_bits = size_bits; return hash; } static struct ftrace_hash * alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) { struct ftrace_func_entry *entry; struct ftrace_hash *new_hash; int size; int ret; int i; new_hash = alloc_ftrace_hash(size_bits); if (!new_hash) return NULL; /* Empty hash? */ if (ftrace_hash_empty(hash)) return new_hash; size = 1 << hash->size_bits; for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { ret = add_hash_entry(new_hash, entry->ip); if (ret < 0) goto free_hash; } } FTRACE_WARN_ON(new_hash->count != hash->count); return new_hash; free_hash: free_ftrace_hash(new_hash); return NULL; } static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash); static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash); static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, struct ftrace_hash *new_hash); static int ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash **dst, struct ftrace_hash *src) { struct ftrace_func_entry *entry; struct hlist_node *tn; struct hlist_head *hhd; struct ftrace_hash *new_hash; int size = src->count; int bits = 0; int ret; int i; /* Reject setting notrace hash on IPMODIFY ftrace_ops */ if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable) return -EINVAL; /* * If the new source is empty, just free dst and assign it * the empty_hash. */ if (!src->count) { new_hash = EMPTY_HASH; goto update; } /* * Make the hash size about 1/2 the # found */ for (size /= 2; size; size >>= 1) bits++; /* Don't allocate too much */ if (bits > FTRACE_HASH_MAX_BITS) bits = FTRACE_HASH_MAX_BITS; new_hash = alloc_ftrace_hash(bits); if (!new_hash) return -ENOMEM; size = 1 << src->size_bits; for (i = 0; i < size; i++) { hhd = &src->buckets[i]; hlist_for_each_entry_safe(entry, tn, hhd, hlist) { remove_hash_entry(src, entry); __add_hash_entry(new_hash, entry); } } update: /* Make sure this can be applied if it is IPMODIFY ftrace_ops */ if (enable) { /* IPMODIFY should be updated only when filter_hash updating */ ret = ftrace_hash_ipmodify_update(ops, new_hash); if (ret < 0) { free_ftrace_hash(new_hash); return ret; } } /* * Remove the current set, update the hash and add * them back. */ ftrace_hash_rec_disable_modify(ops, enable); rcu_assign_pointer(*dst, new_hash); ftrace_hash_rec_enable_modify(ops, enable); return 0; } static bool hash_contains_ip(unsigned long ip, struct ftrace_ops_hash *hash) { /* * The function record is a match if it exists in the filter * hash and not in the notrace hash. Note, an emty hash is * considered a match for the filter hash, but an empty * notrace hash is considered not in the notrace hash. */ return (ftrace_hash_empty(hash->filter_hash) || ftrace_lookup_ip(hash->filter_hash, ip)) && (ftrace_hash_empty(hash->notrace_hash) || !ftrace_lookup_ip(hash->notrace_hash, ip)); } /* * Test the hashes for this ops to see if we want to call * the ops->func or not. * * It's a match if the ip is in the ops->filter_hash or * the filter_hash does not exist or is empty, * AND * the ip is not in the ops->notrace_hash. * * This needs to be called with preemption disabled as * the hashes are freed with call_rcu_sched(). */ static int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) { struct ftrace_ops_hash hash; int ret; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * There's a small race when adding ops that the ftrace handler * that wants regs, may be called without them. We can not * allow that handler to be called if regs is NULL. */ if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS)) return 0; #endif hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash); hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash); if (hash_contains_ip(ip, &hash)) ret = 1; else ret = 0; return ret; } /* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. */ #define do_for_each_ftrace_rec(pg, rec) \ for (pg = ftrace_pages_start; pg; pg = pg->next) { \ int _____i; \ for (_____i = 0; _____i < pg->index; _____i++) { \ rec = &pg->records[_____i]; #define while_for_each_ftrace_rec() \ } \ } static int ftrace_cmp_recs(const void *a, const void *b) { const struct dyn_ftrace *key = a; const struct dyn_ftrace *rec = b; if (key->flags < rec->ip) return -1; if (key->ip >= rec->ip + MCOUNT_INSN_SIZE) return 1; return 0; } static unsigned long ftrace_location_range(unsigned long start, unsigned long end) { struct ftrace_page *pg; struct dyn_ftrace *rec; struct dyn_ftrace key; key.ip = start; key.flags = end; /* overload flags, as it is unsigned long */ for (pg = ftrace_pages_start; pg; pg = pg->next) { if (end < pg->records[0].ip || start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) continue; rec = bsearch(&key, pg->records, pg->index, sizeof(struct dyn_ftrace), ftrace_cmp_recs); if (rec) return rec->ip; } return 0; } /** * ftrace_location - return true if the ip giving is a traced location * @ip: the instruction pointer to check * * Returns rec->ip if @ip given is a pointer to a ftrace location. * That is, the instruction that is either a NOP or call to * the function tracer. It checks the ftrace internal tables to * determine if the address belongs or not. */ unsigned long ftrace_location(unsigned long ip) { return ftrace_location_range(ip, ip); } /** * ftrace_text_reserved - return true if range contains an ftrace location * @start: start of range to search * @end: end of range to search (inclusive). @end points to the last byte to check. * * Returns 1 if @start and @end contains a ftrace location. * That is, the instruction that is either a NOP or call to * the function tracer. It checks the ftrace internal tables to * determine if the address belongs or not. */ int ftrace_text_reserved(const void *start, const void *end) { unsigned long ret; ret = ftrace_location_range((unsigned long)start, (unsigned long)end); return (int)!!ret; } /* Test if ops registered to this rec needs regs */ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) { struct ftrace_ops *ops; bool keep_regs = false; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { /* pass rec in as regs to have non-NULL val */ if (ftrace_ops_test(ops, rec->ip, rec)) { if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { keep_regs = true; break; } } } return keep_regs; } static void __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) { struct ftrace_hash *hash; struct ftrace_hash *other_hash; struct ftrace_page *pg; struct dyn_ftrace *rec; int count = 0; int all = 0; /* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return; /* * In the filter_hash case: * If the count is zero, we update all records. * Otherwise we just update the items in the hash. * * In the notrace_hash case: * We enable the update in the hash. * As disabling notrace means enabling the tracing, * and enabling notrace means disabling, the inc variable * gets inversed. */ if (filter_hash) { hash = ops->func_hash->filter_hash; other_hash = ops->func_hash->notrace_hash; if (ftrace_hash_empty(hash)) all = 1; } else { inc = !inc; hash = ops->func_hash->notrace_hash; other_hash = ops->func_hash->filter_hash; /* * If the notrace hash has no items, * then there's nothing to do. */ if (ftrace_hash_empty(hash)) return; } do_for_each_ftrace_rec(pg, rec) { int in_other_hash = 0; int in_hash = 0; int match = 0; if (all) { /* * Only the filter_hash affects all records. * Update if the record is not in the notrace hash. */ if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) match = 1; } else { in_hash = !!ftrace_lookup_ip(hash, rec->ip); in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); /* * If filter_hash is set, we want to match all functions * that are in the hash but not in the other hash. * * If filter_hash is not set, then we are decrementing. * That means we match anything that is in the hash * and also in the other_hash. That is, we need to turn * off functions in the other hash because they are disabled * by this hash. */ if (filter_hash && in_hash && !in_other_hash) match = 1; else if (!filter_hash && in_hash && (in_other_hash || ftrace_hash_empty(other_hash))) match = 1; } if (!match) continue; if (inc) { rec->flags++; if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return; /* * If there's only a single callback registered to a * function, and the ops has a trampoline registered * for it, then we can call it directly. */ if (ftrace_rec_count(rec) == 1 && ops->trampoline) rec->flags |= FTRACE_FL_TRAMP; else /* * If we are adding another function callback * to this function, and the previous had a * custom trampoline in use, then we need to go * back to the default trampoline. */ rec->flags &= ~FTRACE_FL_TRAMP; /* * If any ops wants regs saved for this function * then all ops will get saved regs. */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; } else { if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return; rec->flags--; /* * If the rec had REGS enabled and the ops that is * being removed had REGS set, then see if there is * still any ops for this record that wants regs. * If not, we can stop recording them. */ if (ftrace_rec_count(rec) > 0 && rec->flags & FTRACE_FL_REGS && ops->flags & FTRACE_OPS_FL_SAVE_REGS) { if (!test_rec_ops_needs_regs(rec)) rec->flags &= ~FTRACE_FL_REGS; } /* * If the rec had TRAMP enabled, then it needs to * be cleared. As TRAMP can only be enabled iff * there is only a single ops attached to it. * In otherwords, always disable it on decrementing. * In the future, we may set it if rec count is * decremented to one, and the ops that is left * has a trampoline. */ rec->flags &= ~FTRACE_FL_TRAMP; /* * flags will be cleared in ftrace_check_record() * if rec count is zero. */ } count++; /* Shortcut, if we handled all records, we are done. */ if (!all && count == hash->count) return; } while_for_each_ftrace_rec(); } static void ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash) { __ftrace_hash_rec_update(ops, filter_hash, 0); } static void ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash) { __ftrace_hash_rec_update(ops, filter_hash, 1); } static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, int filter_hash, int inc) { struct ftrace_ops *op; __ftrace_hash_rec_update(ops, filter_hash, inc); if (ops->func_hash != &global_ops.local_hash) return; /* * If the ops shares the global_ops hash, then we need to update * all ops that are enabled and use this hash. */ do_for_each_ftrace_op(op, ftrace_ops_list) { /* Already done */ if (op == ops) continue; if (op->func_hash == &global_ops.local_hash) __ftrace_hash_rec_update(op, filter_hash, inc); } while_for_each_ftrace_op(op); } static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash) { ftrace_hash_rec_update_modify(ops, filter_hash, 0); } static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash) { ftrace_hash_rec_update_modify(ops, filter_hash, 1); } /* * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK * or no-needed to update, -EBUSY if it detects a conflict of the flag * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs. * Note that old_hash and new_hash has below meanings * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected) * - If the hash is EMPTY_HASH, it hits nothing * - Anything else hits the recs which match the hash entries. */ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, struct ftrace_hash *old_hash, struct ftrace_hash *new_hash) { struct ftrace_page *pg; struct dyn_ftrace *rec, *end = NULL; int in_old, in_new; /* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return 0; if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) return 0; /* * Since the IPMODIFY is a very address sensitive action, we do not * allow ftrace_ops to set all functions to new hash. */ if (!new_hash || !old_hash) return -EINVAL; /* Update rec->flags */ do_for_each_ftrace_rec(pg, rec) { /* We need to update only differences of filter_hash */ in_old = !!ftrace_lookup_ip(old_hash, rec->ip); in_new = !!ftrace_lookup_ip(new_hash, rec->ip); if (in_old == in_new) continue; if (in_new) { /* New entries must ensure no others are using it */ if (rec->flags & FTRACE_FL_IPMODIFY) goto rollback; rec->flags |= FTRACE_FL_IPMODIFY; } else /* Removed entry */ rec->flags &= ~FTRACE_FL_IPMODIFY; } while_for_each_ftrace_rec(); return 0; rollback: end = rec; /* Roll back what we did above */ do_for_each_ftrace_rec(pg, rec) { if (rec == end) goto err_out; in_old = !!ftrace_lookup_ip(old_hash, rec->ip); in_new = !!ftrace_lookup_ip(new_hash, rec->ip); if (in_old == in_new) continue; if (in_new) rec->flags &= ~FTRACE_FL_IPMODIFY; else rec->flags |= FTRACE_FL_IPMODIFY; } while_for_each_ftrace_rec(); err_out: return -EBUSY; } static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops) { struct ftrace_hash *hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(hash)) hash = NULL; return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash); } /* Disabling always succeeds */ static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops) { struct ftrace_hash *hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(hash)) hash = NULL; __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH); } static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, struct ftrace_hash *new_hash) { struct ftrace_hash *old_hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(old_hash)) old_hash = NULL; if (ftrace_hash_empty(new_hash)) new_hash = NULL; return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash); } static void print_ip_ins(const char *fmt, unsigned char *p) { char ins[MCOUNT_INSN_SIZE]; int i; if (probe_kernel_read(ins, p, MCOUNT_INSN_SIZE)) { printk(KERN_CONT "%s[FAULT] %px\n", fmt, p); return; } printk(KERN_CONT "%s", fmt); for (i = 0; i < MCOUNT_INSN_SIZE; i++) printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]); } static struct ftrace_ops * ftrace_find_tramp_ops_any(struct dyn_ftrace *rec); /** * ftrace_bug - report and shutdown function tracer * @failed: The failed type (EFAULT, EINVAL, EPERM) * @rec: The record that failed * * The arch code that enables or disables the function tracing * can call ftrace_bug() when it has detected a problem in * modifying the code. @failed should be one of either: * EFAULT - if the problem happens on reading the @ip address * EINVAL - if what is read at @ip is not what was expected * EPERM - if the problem happens on writting to the @ip address */ void ftrace_bug(int failed, struct dyn_ftrace *rec) { unsigned long ip = rec ? rec->ip : 0; switch (failed) { case -EFAULT: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on modifying "); print_ip_sym(ip); break; case -EINVAL: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace failed to modify "); print_ip_sym(ip); print_ip_ins(" actual: ", (unsigned char *)ip); pr_cont("\n"); break; case -EPERM: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on writing "); print_ip_sym(ip); break; default: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on unknown error "); print_ip_sym(ip); } if (rec) { struct ftrace_ops *ops = NULL; pr_info("ftrace record flags: %lx\n", rec->flags); pr_cont(" (%ld)%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); if (ops) pr_cont("\ttramp: %pS", (void *)ops->trampoline); else pr_cont("\ttramp: ERROR!"); } ip = ftrace_get_addr_curr(rec); pr_cont(" expected tramp: %lx\n", ip); } } static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) { unsigned long flag = 0UL; /* * If we are updating calls: * * If the record has a ref count, then we need to enable it * because someone is using it. * * Otherwise we make sure its disabled. * * If we are disabling calls, then disable all records that * are enabled. */ if (enable && ftrace_rec_count(rec)) flag = FTRACE_FL_ENABLED; /* * If enabling and the REGS flag does not match the REGS_EN, or * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore * this record. Set flags to fail the compare against ENABLED. */ if (flag) { if (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)) flag |= FTRACE_FL_REGS; if (!(rec->flags & FTRACE_FL_TRAMP) != !(rec->flags & FTRACE_FL_TRAMP_EN)) flag |= FTRACE_FL_TRAMP; } /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) return FTRACE_UPDATE_IGNORE; if (flag) { /* Save off if rec is being enabled (for return value) */ flag ^= rec->flags & FTRACE_FL_ENABLED; if (update) { rec->flags |= FTRACE_FL_ENABLED; if (flag & FTRACE_FL_REGS) { if (rec->flags & FTRACE_FL_REGS) rec->flags |= FTRACE_FL_REGS_EN; else rec->flags &= ~FTRACE_FL_REGS_EN; } if (flag & FTRACE_FL_TRAMP) { if (rec->flags & FTRACE_FL_TRAMP) rec->flags |= FTRACE_FL_TRAMP_EN; else rec->flags &= ~FTRACE_FL_TRAMP_EN; } } /* * If this record is being updated from a nop, then * return UPDATE_MAKE_CALL. * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert * from the save regs, to a non-save regs function or * vice versa, or from a trampoline call. */ if (flag & FTRACE_FL_ENABLED) return FTRACE_UPDATE_MAKE_CALL; return FTRACE_UPDATE_MODIFY_CALL; } if (update) { /* If there's no more users, clear all flags */ if (!ftrace_rec_count(rec)) rec->flags = 0; else /* * Just disable the record, but keep the ops TRAMP * and REGS states. The _EN flags must be disabled though. */ rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN | FTRACE_FL_REGS_EN); } return FTRACE_UPDATE_MAKE_NOP; } /** * ftrace_update_record, set a record that now is tracing or not * @rec: the record to update * @enable: set to 1 if the record is tracing, zero to force disable * * The records that represent all functions that can be traced need * to be updated when tracing has been enabled. */ int ftrace_update_record(struct dyn_ftrace *rec, int enable) { return ftrace_check_record(rec, enable, 1); } /** * ftrace_test_record, check if the record has been enabled or not * @rec: the record to test * @enable: set to 1 to check if enabled, 0 if it is disabled * * The arch code may need to test if a record is already set to * tracing to determine how to modify the function code that it * represents. */ int ftrace_test_record(struct dyn_ftrace *rec, int enable) { return ftrace_check_record(rec, enable, 0); } static struct ftrace_ops * ftrace_find_tramp_ops_any(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; do_for_each_ftrace_op(op, ftrace_ops_list) { if (!op->trampoline) continue; if (hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } static struct ftrace_ops * ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; /* * Need to check removed ops first. * If they are being removed, and this rec has a tramp, * and this rec is in the ops list, then it would be the * one with the tramp. */ if (removed_ops) { if (hash_contains_ip(ip, &removed_ops->old_hash)) return removed_ops; } /* * Need to find the current trampoline for a rec. * Now, a trampoline is only attached to a rec if there * was a single 'ops' attached to it. But this can be called * when we are adding another op to the rec or removing the * current one. Thus, if the op is being added, we can * ignore it because it hasn't attached itself to the rec * yet. * * If an ops is being modified (hooking to different functions) * then we don't care about the new functions that are being * added, just the old ones (that are probably being removed). * * If we are adding an ops to a function that already is using * a trampoline, it needs to be removed (trampolines are only * for single ops connected), then an ops that is not being * modified also needs to be checked. */ do_for_each_ftrace_op(op, ftrace_ops_list) { if (!op->trampoline) continue; /* * If the ops is being added, it hasn't gotten to * the point to be removed from this tree yet. */ if (op->flags & FTRACE_OPS_FL_ADDING) continue; /* * If the ops is being modified and is in the old * hash, then it is probably being removed from this * function. */ if ((op->flags & FTRACE_OPS_FL_MODIFYING) && hash_contains_ip(ip, &op->old_hash)) return op; /* * If the ops is not being added or modified, and it's * in its normal filter hash, then this must be the one * we want! */ if (!(op->flags & FTRACE_OPS_FL_MODIFYING) && hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } static struct ftrace_ops * ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; do_for_each_ftrace_op(op, ftrace_ops_list) { /* pass rec in as regs to have non-NULL val */ if (hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } /** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor * * If the record has the FTRACE_FL_REGS set, that means that it * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS * is not not set, then it wants to convert to the normal callback. * * Returns the address of the trampoline to set to */ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) { struct ftrace_ops *ops; /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP) { ops = ftrace_find_tramp_ops_new(rec); if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n", (void *)rec->ip, (void *)rec->ip, rec->flags); /* Ftrace is shutting down, return anything */ return (unsigned long)FTRACE_ADDR; } return ops->trampoline; } if (rec->flags & FTRACE_FL_REGS) return (unsigned long)FTRACE_REGS_ADDR; else return (unsigned long)FTRACE_ADDR; } /** * ftrace_get_addr_curr - Get the call address that is already there * @rec: The ftrace record descriptor * * The FTRACE_FL_REGS_EN is set when the record already points to * a function that saves all the regs. Basically the '_EN' version * represents the current state of the function. * * Returns the address of the trampoline that is currently being called */ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) { struct ftrace_ops *ops; /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_curr(rec); if (FTRACE_WARN_ON(!ops)) { pr_warning("Bad trampoline accounting at: %p (%pS)\n", (void *)rec->ip, (void *)rec->ip); /* Ftrace is shutting down, return anything */ return (unsigned long)FTRACE_ADDR; } return ops->trampoline; } if (rec->flags & FTRACE_FL_REGS_EN) return (unsigned long)FTRACE_REGS_ADDR; else return (unsigned long)FTRACE_ADDR; } static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { unsigned long ftrace_old_addr; unsigned long ftrace_addr; int ret; ftrace_addr = ftrace_get_addr_new(rec); /* This needs to be done before we call ftrace_update_record */ ftrace_old_addr = ftrace_get_addr_curr(rec); ret = ftrace_update_record(rec, enable); switch (ret) { case FTRACE_UPDATE_IGNORE: return 0; case FTRACE_UPDATE_MAKE_CALL: return ftrace_make_call(rec, ftrace_addr); case FTRACE_UPDATE_MAKE_NOP: return ftrace_make_nop(NULL, rec, ftrace_old_addr); case FTRACE_UPDATE_MODIFY_CALL: return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); } return -1; /* unknow ftrace bug */ } void __weak ftrace_replace_code(int enable) { struct dyn_ftrace *rec; struct ftrace_page *pg; int failed; if (unlikely(ftrace_disabled)) return; do_for_each_ftrace_rec(pg, rec) { failed = __ftrace_replace_code(rec, enable); if (failed) { ftrace_bug(failed, rec); /* Stop processing */ return; } } while_for_each_ftrace_rec(); } struct ftrace_rec_iter { struct ftrace_page *pg; int index; }; /** * ftrace_rec_iter_start, start up iterating over traced functions * * Returns an iterator handle that is used to iterate over all * the records that represent address locations where functions * are traced. * * May return NULL if no records are available. */ struct ftrace_rec_iter *ftrace_rec_iter_start(void) { /* * We only use a single iterator. * Protected by the ftrace_lock mutex. */ static struct ftrace_rec_iter ftrace_rec_iter; struct ftrace_rec_iter *iter = &ftrace_rec_iter; iter->pg = ftrace_pages_start; iter->index = 0; /* Could have empty pages */ while (iter->pg && !iter->pg->index) iter->pg = iter->pg->next; if (!iter->pg) return NULL; return iter; } /** * ftrace_rec_iter_next, get the next record to process. * @iter: The handle to the iterator. * * Returns the next iterator after the given iterator @iter. */ struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter) { iter->index++; if (iter->index >= iter->pg->index) { iter->pg = iter->pg->next; iter->index = 0; /* Could have empty pages */ while (iter->pg && !iter->pg->index) iter->pg = iter->pg->next; } if (!iter->pg) return NULL; return iter; } /** * ftrace_rec_iter_record, get the record at the iterator location * @iter: The current iterator location * * Returns the record that the current @iter is at. */ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) { return &iter->pg->records[iter->index]; } static int ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) { int ret; if (unlikely(ftrace_disabled)) return 0; ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); if (ret) { ftrace_bug(ret, rec); return 0; } return 1; } /* * archs can override this function if they must do something * before the modifying code is performed. */ int __weak ftrace_arch_code_modify_prepare(void) { return 0; } /* * archs can override this function if they must do something * after the modifying code is performed. */ int __weak ftrace_arch_code_modify_post_process(void) { return 0; } void ftrace_modify_all_code(int command) { int update = command & FTRACE_UPDATE_TRACE_FUNC; int err = 0; /* * If the ftrace_caller calls a ftrace_ops func directly, * we need to make sure that it only traces functions it * expects to trace. When doing the switch of functions, * we need to update to the ftrace_ops_list_func first * before the transition between old and new calls are set, * as the ftrace_ops_list_func will check the ops hashes * to make sure the ops are having the right functions * traced. */ if (update) { err = ftrace_update_ftrace_func(ftrace_ops_list_func); if (FTRACE_WARN_ON(err)) return; } if (command & FTRACE_UPDATE_CALLS) ftrace_replace_code(1); else if (command & FTRACE_DISABLE_CALLS) ftrace_replace_code(0); if (update && ftrace_trace_function != ftrace_ops_list_func) { function_trace_op = set_function_trace_op; smp_wmb(); /* If irqs are disabled, we are in stop machine */ if (!irqs_disabled()) smp_call_function(ftrace_sync_ipi, NULL, 1); err = ftrace_update_ftrace_func(ftrace_trace_function); if (FTRACE_WARN_ON(err)) return; } if (command & FTRACE_START_FUNC_RET) err = ftrace_enable_ftrace_graph_caller(); else if (command & FTRACE_STOP_FUNC_RET) err = ftrace_disable_ftrace_graph_caller(); FTRACE_WARN_ON(err); } static int __ftrace_modify_code(void *data) { int *command = data; ftrace_modify_all_code(*command); return 0; } /** * ftrace_run_stop_machine, go back to the stop machine method * @command: The command to tell ftrace what to do * * If an arch needs to fall back to the stop machine method, the * it can call this function. */ void ftrace_run_stop_machine(int command) { stop_machine(__ftrace_modify_code, &command, NULL); } /** * arch_ftrace_update_code, modify the code to trace or not trace * @command: The command that needs to be done * * Archs can override this function if it does not need to * run stop_machine() to modify code. */ void __weak arch_ftrace_update_code(int command) { ftrace_run_stop_machine(command); } static void ftrace_run_update_code(int command) { int ret; ret = ftrace_arch_code_modify_prepare(); FTRACE_WARN_ON(ret); if (ret) return; /* * By default we use stop_machine() to modify the code. * But archs can do what ever they want as long as it * is safe. The stop_machine() is the safest, but also * produces the most overhead. */ arch_ftrace_update_code(command); ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); } static void ftrace_run_modify_code(struct ftrace_ops *ops, int command, struct ftrace_ops_hash *old_hash) { ops->flags |= FTRACE_OPS_FL_MODIFYING; ops->old_hash.filter_hash = old_hash->filter_hash; ops->old_hash.notrace_hash = old_hash->notrace_hash; ftrace_run_update_code(command); ops->old_hash.filter_hash = NULL; ops->old_hash.notrace_hash = NULL; ops->flags &= ~FTRACE_OPS_FL_MODIFYING; } static ftrace_func_t saved_ftrace_func; static int ftrace_start_up; void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) { } static void control_ops_free(struct ftrace_ops *ops) { free_percpu(ops->disabled); } static void ftrace_startup_enable(int command) { if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) return; ftrace_run_update_code(command); } static void ftrace_startup_all(int command) { update_all_ops = true; ftrace_startup_enable(command); update_all_ops = false; } static int ftrace_startup(struct ftrace_ops *ops, int command) { int ret; if (unlikely(ftrace_disabled)) return -ENODEV; ret = __register_ftrace_function(ops); if (ret) return ret; ftrace_start_up++; command |= FTRACE_UPDATE_CALLS; /* * Note that ftrace probes uses this to start up * and modify functions it will probe. But we still * set the ADDING flag for modification, as probes * do not have trampolines. If they add them in the * future, then the probes will need to distinguish * between adding and updating probes. */ ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING; ret = ftrace_hash_ipmodify_enable(ops); if (ret < 0) { /* Rollback registration process */ __unregister_ftrace_function(ops); ftrace_start_up--; ops->flags &= ~FTRACE_OPS_FL_ENABLED; return ret; } ftrace_hash_rec_enable(ops, 1); ftrace_startup_enable(command); ops->flags &= ~FTRACE_OPS_FL_ADDING; return 0; } static int ftrace_shutdown(struct ftrace_ops *ops, int command) { int ret; if (unlikely(ftrace_disabled)) return -ENODEV; ret = __unregister_ftrace_function(ops); if (ret) return ret; ftrace_start_up--; /* * Just warn in case of unbalance, no need to kill ftrace, it's not * critical but the ftrace_call callers may be never nopped again after * further ftrace uses. */ WARN_ON_ONCE(ftrace_start_up < 0); /* Disabling ipmodify never fails */ ftrace_hash_ipmodify_disable(ops); ftrace_hash_rec_disable(ops, 1); ops->flags &= ~FTRACE_OPS_FL_ENABLED; command |= FTRACE_UPDATE_CALLS; if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) { /* * If these are dynamic or control ops, they still * need their data freed. Since, function tracing is * not currently active, we can just free them * without synchronizing all CPUs. */ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) goto free_ops; return 0; } /* * If the ops uses a trampoline, then it needs to be * tested first on update. */ ops->flags |= FTRACE_OPS_FL_REMOVING; removed_ops = ops; /* The trampoline logic checks the old hashes */ ops->old_hash.filter_hash = ops->func_hash->filter_hash; ops->old_hash.notrace_hash = ops->func_hash->notrace_hash; ftrace_run_update_code(command); /* * If there's no more ops registered with ftrace, run a * sanity check to make sure all rec flags are cleared. */ if (ftrace_ops_list == &ftrace_list_end) { struct ftrace_page *pg; struct dyn_ftrace *rec; do_for_each_ftrace_rec(pg, rec) { if (FTRACE_WARN_ON_ONCE(rec->flags)) pr_warn(" %pS flags:%lx\n", (void *)rec->ip, rec->flags); } while_for_each_ftrace_rec(); } ops->old_hash.filter_hash = NULL; ops->old_hash.notrace_hash = NULL; removed_ops = NULL; ops->flags &= ~FTRACE_OPS_FL_REMOVING; /* * Dynamic ops may be freed, we must make sure that all * callers are done before leaving this function. * The same goes for freeing the per_cpu data of the control * ops. * * Again, normal synchronize_sched() is not good enough. * We need to do a hard force of sched synchronization. * This is because we use preempt_disable() to do RCU, but * the function tracers can be called where RCU is not watching * (like before user_exit()). We can not rely on the RCU * infrastructure to do the synchronization, thus we must do it * ourselves. */ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) { schedule_on_each_cpu(ftrace_sync); free_ops: arch_ftrace_trampoline_free(ops); if (ops->flags & FTRACE_OPS_FL_CONTROL) control_ops_free(ops); } return 0; } static void ftrace_startup_sysctl(void) { int command; if (unlikely(ftrace_disabled)) return; /* Force update next time */ saved_ftrace_func = NULL; /* ftrace_start_up is true if we want ftrace running */ if (ftrace_start_up) { command = FTRACE_UPDATE_CALLS; if (ftrace_graph_active) command |= FTRACE_START_FUNC_RET; ftrace_startup_enable(command); } } static void ftrace_shutdown_sysctl(void) { int command; if (unlikely(ftrace_disabled)) return; /* ftrace_start_up is true if ftrace is running */ if (ftrace_start_up) { command = FTRACE_DISABLE_CALLS; if (ftrace_graph_active) command |= FTRACE_STOP_FUNC_RET; ftrace_run_update_code(command); } } static cycle_t ftrace_update_time; unsigned long ftrace_update_tot_cnt; static inline int ops_traces_mod(struct ftrace_ops *ops) { /* * Filter_hash being empty will default to trace module. * But notrace hash requires a test of individual module functions. */ return ftrace_hash_empty(ops->func_hash->filter_hash) && ftrace_hash_empty(ops->func_hash->notrace_hash); } /* * Check if the current ops references the record. * * If the ops traces all functions, then it was already accounted for. * If the ops does not trace the current record function, skip it. * If the ops ignores the function via notrace filter, skip it. */ static inline bool ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec) { /* If ops isn't enabled, ignore it */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return 0; /* If ops traces all mods, we already accounted for it */ if (ops_traces_mod(ops)) return 0; /* The function must be in the filter */ if (!ftrace_hash_empty(ops->func_hash->filter_hash) && !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) return 0; /* If in notrace hash, we ignore it too */ if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) return 0; return 1; } static int referenced_filters(struct dyn_ftrace *rec) { struct ftrace_ops *ops; int cnt = 0; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { if (ops_references_rec(ops, rec)) { cnt++; if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; } } return cnt; } static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) { struct ftrace_page *pg; struct dyn_ftrace *p; cycle_t start, stop; unsigned long update_cnt = 0; unsigned long ref = 0; bool test = false; int i; /* * When adding a module, we need to check if tracers are * currently enabled and if they are set to trace all functions. * If they are, we need to enable the module functions as well * as update the reference counts for those function records. */ if (mod) { struct ftrace_ops *ops; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { if (ops->flags & FTRACE_OPS_FL_ENABLED) { if (ops_traces_mod(ops)) ref++; else test = true; } } } start = ftrace_now(raw_smp_processor_id()); for (pg = new_pgs; pg; pg = pg->next) { for (i = 0; i < pg->index; i++) { int cnt = ref; /* If something went wrong, bail without enabling anything */ if (unlikely(ftrace_disabled)) return -1; p = &pg->records[i]; if (test) cnt += referenced_filters(p); p->flags += cnt; /* * Do the initial record conversion from mcount jump * to the NOP instructions. */ if (!ftrace_code_disable(mod, p)) break; update_cnt++; /* * If the tracing is enabled, go ahead and enable the record. * * The reason not to enable the record immediatelly is the * inherent check of ftrace_make_nop/ftrace_make_call for * correct previous instructions. Making first the NOP * conversion puts the module to the correct state, thus * passing the ftrace_make_call check. */ if (ftrace_start_up && cnt) { int failed = __ftrace_replace_code(p, 1); if (failed) ftrace_bug(failed, p); } } } stop = ftrace_now(raw_smp_processor_id()); ftrace_update_time = stop - start; ftrace_update_tot_cnt += update_cnt; return 0; } static int ftrace_allocate_records(struct ftrace_page *pg, int count) { int order; int cnt; if (WARN_ON(!count)) return -EINVAL; order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); /* * We want to fill as much as possible. No more than a page * may be empty. */ while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) order--; again: pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); if (!pg->records) { /* if we can't allocate this size, try something smaller */ if (!order) return -ENOMEM; order >>= 1; goto again; } cnt = (PAGE_SIZE << order) / ENTRY_SIZE; pg->size = cnt; if (cnt > count) cnt = count; return cnt; } static struct ftrace_page * ftrace_allocate_pages(unsigned long num_to_init) { struct ftrace_page *start_pg; struct ftrace_page *pg; int order; int cnt; if (!num_to_init) return 0; start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg) return NULL; /* * Try to allocate as much as possible in one continues * location that fills in all of the space. We want to * waste as little space as possible. */ for (;;) { cnt = ftrace_allocate_records(pg, num_to_init); if (cnt < 0) goto free_pages; num_to_init -= cnt; if (!num_to_init) break; pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg->next) goto free_pages; pg = pg->next; } return start_pg; free_pages: pg = start_pg; while (pg) { order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); start_pg = pg->next; kfree(pg); pg = start_pg; } pr_info("ftrace: FAILED to allocate memory for functions\n"); return NULL; } #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ struct ftrace_iterator { loff_t pos; loff_t func_pos; struct ftrace_page *pg; struct dyn_ftrace *func; struct ftrace_func_probe *probe; struct trace_parser parser; struct ftrace_hash *hash; struct ftrace_ops *ops; int hidx; int idx; unsigned flags; }; static void * t_hash_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct hlist_node *hnd = NULL; struct hlist_head *hhd; (*pos)++; iter->pos = *pos; if (iter->probe) hnd = &iter->probe->node; retry: if (iter->hidx >= FTRACE_FUNC_HASHSIZE) return NULL; hhd = &ftrace_func_hash[iter->hidx]; if (hlist_empty(hhd)) { iter->hidx++; hnd = NULL; goto retry; } if (!hnd) hnd = hhd->first; else { hnd = hnd->next; if (!hnd) { iter->hidx++; goto retry; } } if (WARN_ON_ONCE(!hnd)) return NULL; iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node); return iter; } static void *t_hash_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; if (!(iter->flags & FTRACE_ITER_DO_HASH)) return NULL; if (iter->func_pos > *pos) return NULL; iter->hidx = 0; for (l = 0; l <= (*pos - iter->func_pos); ) { p = t_hash_next(m, &l); if (!p) break; } if (!p) return NULL; /* Only set this if we have an item */ iter->flags |= FTRACE_ITER_HASH; return iter; } static int t_hash_show(struct seq_file *m, struct ftrace_iterator *iter) { struct ftrace_func_probe *rec; rec = iter->probe; if (WARN_ON_ONCE(!rec)) return -EIO; if (rec->ops->print) return rec->ops->print(m, rec->ip, rec->ops, rec->data); seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func); if (rec->data) seq_printf(m, ":%p", rec->data); seq_putc(m, '\n'); return 0; } static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct ftrace_ops *ops = iter->ops; struct dyn_ftrace *rec = NULL; if (unlikely(ftrace_disabled)) return NULL; if (iter->flags & FTRACE_ITER_HASH) return t_hash_next(m, pos); (*pos)++; iter->pos = iter->func_pos = *pos; if (iter->flags & FTRACE_ITER_PRINTALL) return t_hash_start(m, pos); retry: if (iter->idx >= iter->pg->index) { if (iter->pg->next) { iter->pg = iter->pg->next; iter->idx = 0; goto retry; } } else { rec = &iter->pg->records[iter->idx++]; if (((iter->flags & FTRACE_ITER_FILTER) && !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) || ((iter->flags & FTRACE_ITER_NOTRACE) && !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) || ((iter->flags & FTRACE_ITER_ENABLED) && !(rec->flags & FTRACE_FL_ENABLED))) { rec = NULL; goto retry; } } if (!rec) return t_hash_start(m, pos); iter->func = rec; return iter; } static void reset_iter_read(struct ftrace_iterator *iter) { iter->pos = 0; iter->func_pos = 0; iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH); } static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct ftrace_ops *ops = iter->ops; void *p = NULL; loff_t l; mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) return NULL; /* * If an lseek was done, then reset and start from beginning. */ if (*pos < iter->pos) reset_iter_read(iter); /* * For set_ftrace_filter reading, if we have the filter * off, we can short cut and just print out that all * functions are enabled. */ if ((iter->flags & FTRACE_ITER_FILTER && ftrace_hash_empty(ops->func_hash->filter_hash)) || (iter->flags & FTRACE_ITER_NOTRACE && ftrace_hash_empty(ops->func_hash->notrace_hash))) { if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; /* reset in case of seek/pread */ iter->flags &= ~FTRACE_ITER_HASH; return iter; } if (iter->flags & FTRACE_ITER_HASH) return t_hash_start(m, pos); /* * Unfortunately, we need to restart at ftrace_pages_start * every time we let go of the ftrace_mutex. This is because * those pointers can change without the lock. */ iter->pg = ftrace_pages_start; iter->idx = 0; for (l = 0; l <= *pos; ) { p = t_next(m, p, &l); if (!p) break; } if (!p) return t_hash_start(m, pos); return iter; } static void t_stop(struct seq_file *m, void *p) { mutex_unlock(&ftrace_lock); } void * __weak arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) { return NULL; } static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, struct dyn_ftrace *rec) { void *ptr; ptr = arch_ftrace_trampoline_func(ops, rec); if (ptr) seq_printf(m, " ->%pS", ptr); } static int t_show(struct seq_file *m, void *v) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec; if (iter->flags & FTRACE_ITER_HASH) return t_hash_show(m, iter); if (iter->flags & FTRACE_ITER_PRINTALL) { if (iter->flags & FTRACE_ITER_NOTRACE) seq_puts(m, "#### no functions disabled ####\n"); else seq_puts(m, "#### all functions enabled ####\n"); return 0; } rec = iter->func; if (!rec) return 0; seq_printf(m, "%ps", (void *)rec->ip); if (iter->flags & FTRACE_ITER_ENABLED) { struct ftrace_ops *ops = NULL; seq_printf(m, " (%ld)%s%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " ", rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); if (ops) seq_printf(m, "\ttramp: %pS", (void *)ops->trampoline); else seq_puts(m, "\ttramp: ERROR!"); } add_trampoline_func(m, ops, rec); } seq_putc(m, '\n'); return 0; } static const struct seq_operations show_ftrace_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, .show = t_show, }; static int ftrace_avail_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; if (unlikely(ftrace_disabled)) return -ENODEV; iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (iter) { iter->pg = ftrace_pages_start; iter->ops = &global_ops; } return iter ? 0 : -ENOMEM; } static int ftrace_enabled_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (iter) { iter->pg = ftrace_pages_start; iter->flags = FTRACE_ITER_ENABLED; iter->ops = &global_ops; } return iter ? 0 : -ENOMEM; } /** * ftrace_regex_open - initialize function tracer filter files * @ops: The ftrace_ops that hold the hash filters * @flag: The type of filter to process * @inode: The inode, usually passed in to your open routine * @file: The file, usually passed in to your open routine * * ftrace_regex_open() initializes the filter files for the * @ops. Depending on @flag it may process the filter hash or * the notrace hash of @ops. With this called from the open * routine, you can use ftrace_filter_write() for the write * routine if @flag has FTRACE_ITER_FILTER set, or * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. * tracing_lseek() should be used as the lseek routine, and * release must call ftrace_regex_release(). */ int ftrace_regex_open(struct ftrace_ops *ops, int flag, struct inode *inode, struct file *file) { struct ftrace_iterator *iter; struct ftrace_hash *hash; int ret = 0; ftrace_ops_init(ops); if (unlikely(ftrace_disabled)) return -ENODEV; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { kfree(iter); return -ENOMEM; } iter->ops = ops; iter->flags = flag; mutex_lock(&ops->func_hash->regex_lock); if (flag & FTRACE_ITER_NOTRACE) hash = ops->func_hash->notrace_hash; else hash = ops->func_hash->filter_hash; if (file->f_mode & FMODE_WRITE) { const int size_bits = FTRACE_HASH_DEFAULT_BITS; if (file->f_flags & O_TRUNC) iter->hash = alloc_ftrace_hash(size_bits); else iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); if (!iter->hash) { trace_parser_put(&iter->parser); kfree(iter); ret = -ENOMEM; goto out_unlock; } } if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = iter; } else { /* Failed */ free_ftrace_hash(iter->hash); trace_parser_put(&iter->parser); kfree(iter); } } else file->private_data = iter; out_unlock: mutex_unlock(&ops->func_hash->regex_lock); return ret; } static int ftrace_filter_open(struct inode *inode, struct file *file) { struct ftrace_ops *ops = inode->i_private; return ftrace_regex_open(ops, FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH, inode, file); } static int ftrace_notrace_open(struct inode *inode, struct file *file) { struct ftrace_ops *ops = inode->i_private; return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE, inode, file); } /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ struct ftrace_glob { char *search; unsigned len; int type; }; static int ftrace_match(char *str, struct ftrace_glob *g) { int matched = 0; int slen; switch (g->type) { case MATCH_FULL: if (strcmp(str, g->search) == 0) matched = 1; break; case MATCH_FRONT_ONLY: if (strncmp(str, g->search, g->len) == 0) matched = 1; break; case MATCH_MIDDLE_ONLY: if (strstr(str, g->search)) matched = 1; break; case MATCH_END_ONLY: slen = strlen(str); if (slen >= g->len && memcmp(str + slen - g->len, g->search, g->len) == 0) matched = 1; break; } return matched; } static int enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter) { struct ftrace_func_entry *entry; int ret = 0; entry = ftrace_lookup_ip(hash, rec->ip); if (clear_filter) { /* Do nothing if it doesn't exist */ if (!entry) return 0; free_hash_entry(hash, entry); } else { /* Do nothing if it exists */ if (entry) return 0; ret = add_hash_entry(hash, rec->ip); } return ret; } static int ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, struct ftrace_glob *mod_g, int exclude_mod) { char str[KSYM_SYMBOL_LEN]; char *modname; kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); if (mod_g) { int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0; /* blank module name to match all modules */ if (!mod_g->len) { /* blank module globbing: modname xor exclude_mod */ if ((!exclude_mod) != (!modname)) goto func_match; return 0; } /* not matching the module */ if (!modname || !mod_matches) { if (exclude_mod) goto func_match; else return 0; } if (mod_matches && exclude_mod) return 0; func_match: /* blank search means to match all funcs in the mod */ if (!func_g->len) return 1; } return ftrace_match(str, func_g); } static int match_records(struct ftrace_hash *hash, char *func, int len, char *mod) { struct ftrace_page *pg; struct dyn_ftrace *rec; struct ftrace_glob func_g = { .type = MATCH_FULL }; struct ftrace_glob mod_g = { .type = MATCH_FULL }; struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; int exclude_mod = 0; int found = 0; int ret; int clear_filter = 0; if (func) { func_g.type = filter_parse_regex(func, len, &func_g.search, &clear_filter); func_g.len = strlen(func_g.search); } if (mod) { mod_g.type = filter_parse_regex(mod, strlen(mod), &mod_g.search, &exclude_mod); mod_g.len = strlen(mod_g.search); } mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) goto out_unlock; do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { ret = enter_record(hash, rec, clear_filter); if (ret < 0) { found = ret; goto out_unlock; } found = 1; } } while_for_each_ftrace_rec(); out_unlock: mutex_unlock(&ftrace_lock); return found; } static int ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) { return match_records(hash, buff, len, NULL); } /* * We register the module command as a template to show others how * to register the a command as well. */ static int ftrace_mod_callback(struct ftrace_hash *hash, char *func, char *cmd, char *module, int enable) { int ret; /* * cmd == 'mod' because we only registered this func * for the 'mod' ftrace_func_command. * But if you register one func with multiple commands, * you can tell which command was used by the cmd * parameter. */ ret = match_records(hash, func, strlen(func), module); if (!ret) return -EINVAL; if (ret < 0) return ret; return 0; } static struct ftrace_func_command ftrace_mod_cmd = { .name = "mod", .func = ftrace_mod_callback, }; static int __init ftrace_mod_cmd_init(void) { return register_ftrace_command(&ftrace_mod_cmd); } core_initcall(ftrace_mod_cmd_init); static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *pt_regs) { struct ftrace_func_probe *entry; struct hlist_head *hhd; unsigned long key; key = hash_long(ip, FTRACE_HASH_BITS); hhd = &ftrace_func_hash[key]; if (hlist_empty(hhd)) return; /* * Disable preemption for these calls to prevent a RCU grace * period. This syncs the hash iteration and freeing of items * on the hash. rcu_read_lock is too dangerous here. */ preempt_disable_notrace(); hlist_for_each_entry_rcu_notrace(entry, hhd, node) { if (entry->ip == ip) entry->ops->func(ip, parent_ip, &entry->data); } preempt_enable_notrace(); } static struct ftrace_ops trace_probe_ops __read_mostly = { .func = function_trace_probe_call, .flags = FTRACE_OPS_FL_INITIALIZED, INIT_OPS_HASH(trace_probe_ops) }; static int ftrace_probe_registered; static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash) { int ret; int i; if (ftrace_probe_registered) { /* still need to update the function call sites */ if (ftrace_enabled) ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS, old_hash); return; } for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; if (hhd->first) break; } /* Nothing registered? */ if (i == FTRACE_FUNC_HASHSIZE) return; ret = ftrace_startup(&trace_probe_ops, 0); ftrace_probe_registered = 1; } static bool __disable_ftrace_function_probe(void) { int i; if (!ftrace_probe_registered) return false; for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; if (hhd->first) return false; } /* no more funcs left */ ftrace_shutdown(&trace_probe_ops, 0); ftrace_probe_registered = 0; return true; } static void ftrace_free_entry(struct ftrace_func_probe *entry) { if (entry->ops->free) entry->ops->free(entry->ops, entry->ip, &entry->data); kfree(entry); } int register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data) { struct ftrace_ops_hash old_hash_ops; struct ftrace_func_probe *entry; struct ftrace_glob func_g; struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash; struct ftrace_hash *old_hash = *orig_hash; struct ftrace_hash *hash; struct ftrace_page *pg; struct dyn_ftrace *rec; int not; unsigned long key; int count = 0; int ret; func_g.type = filter_parse_regex(glob, strlen(glob), &func_g.search, ¬); func_g.len = strlen(func_g.search); /* we do not support '!' for function probes */ if (WARN_ON(not)) return -EINVAL; mutex_lock(&trace_probe_ops.func_hash->regex_lock); old_hash_ops.filter_hash = old_hash; /* Probes only have filters */ old_hash_ops.notrace_hash = NULL; hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); if (!hash) { count = -ENOMEM; goto out; } if (unlikely(ftrace_disabled)) { count = -ENODEV; goto out; } mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { if (!ftrace_match_record(rec, &func_g, NULL, 0)) continue; entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) { /* If we did not process any, then return error */ if (!count) count = -ENOMEM; goto out_unlock; } count++; entry->data = data; /* * The caller might want to do something special * for each function we find. We call the callback * to give the caller an opportunity to do so. */ if (ops->init) { if (ops->init(ops, rec->ip, &entry->data) < 0) { /* caller does not like this func */ kfree(entry); continue; } } ret = enter_record(hash, rec, 0); if (ret < 0) { kfree(entry); count = ret; goto out_unlock; } entry->ops = ops; entry->ip = rec->ip; key = hash_long(entry->ip, FTRACE_HASH_BITS); hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]); } while_for_each_ftrace_rec(); ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash); __enable_ftrace_function_probe(&old_hash_ops); if (!ret) free_ftrace_hash_rcu(old_hash); else count = ret; out_unlock: mutex_unlock(&ftrace_lock); out: mutex_unlock(&trace_probe_ops.func_hash->regex_lock); free_ftrace_hash(hash); return count; } enum { PROBE_TEST_FUNC = 1, PROBE_TEST_DATA = 2 }; static void __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data, int flags) { struct ftrace_ops_hash old_hash_ops; struct ftrace_func_entry *rec_entry; struct ftrace_func_probe *entry; struct ftrace_func_probe *p; struct ftrace_glob func_g; struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash; struct ftrace_hash *old_hash = *orig_hash; struct list_head free_list; struct ftrace_hash *hash; struct hlist_node *tmp; char str[KSYM_SYMBOL_LEN]; int i, ret; bool disabled; if (glob && (strcmp(glob, "*") == 0 || !strlen(glob))) func_g.search = NULL; else if (glob) { int not; func_g.type = filter_parse_regex(glob, strlen(glob), &func_g.search, ¬); func_g.len = strlen(func_g.search); /* we do not support '!' for function probes */ if (WARN_ON(not)) return; } mutex_lock(&trace_probe_ops.func_hash->regex_lock); old_hash_ops.filter_hash = old_hash; /* Probes only have filters */ old_hash_ops.notrace_hash = NULL; hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); if (!hash) /* Hmm, should report this somehow */ goto out_unlock; INIT_LIST_HEAD(&free_list); for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) { struct hlist_head *hhd = &ftrace_func_hash[i]; hlist_for_each_entry_safe(entry, tmp, hhd, node) { /* break up if statements for readability */ if ((flags & PROBE_TEST_FUNC) && entry->ops != ops) continue; if ((flags & PROBE_TEST_DATA) && entry->data != data) continue; /* do this last, since it is the most expensive */ if (func_g.search) { kallsyms_lookup(entry->ip, NULL, NULL, NULL, str); if (!ftrace_match(str, &func_g)) continue; } rec_entry = ftrace_lookup_ip(hash, entry->ip); /* It is possible more than one entry had this ip */ if (rec_entry) free_hash_entry(hash, rec_entry); hlist_del_rcu(&entry->node); list_add(&entry->free_list, &free_list); } } mutex_lock(&ftrace_lock); disabled = __disable_ftrace_function_probe(); /* * Remove after the disable is called. Otherwise, if the last * probe is removed, a null hash means *all enabled*. */ ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash); /* still need to update the function call sites */ if (ftrace_enabled && !disabled) ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS, &old_hash_ops); synchronize_sched(); if (!ret) free_ftrace_hash_rcu(old_hash); list_for_each_entry_safe(entry, p, &free_list, free_list) { list_del(&entry->free_list); ftrace_free_entry(entry); } mutex_unlock(&ftrace_lock); out_unlock: mutex_unlock(&trace_probe_ops.func_hash->regex_lock); free_ftrace_hash(hash); } void unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, void *data) { __unregister_ftrace_function_probe(glob, ops, data, PROBE_TEST_FUNC | PROBE_TEST_DATA); } void unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops) { __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC); } void unregister_ftrace_function_probe_all(char *glob) { __unregister_ftrace_function_probe(glob, NULL, NULL, 0); } static LIST_HEAD(ftrace_commands); static DEFINE_MUTEX(ftrace_cmd_mutex); /* * Currently we only register ftrace commands from __init, so mark this * __init too. */ __init int register_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p; int ret = 0; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = -EBUSY; goto out_unlock; } } list_add(&cmd->list, &ftrace_commands); out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } /* * Currently we only unregister ftrace commands from __init, so mark * this __init too. */ __init int unregister_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p, *n; int ret = -ENODEV; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry_safe(p, n, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = 0; list_del_init(&p->list); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static int ftrace_process_regex(struct ftrace_hash *hash, char *buff, int len, int enable) { char *func, *command, *next = buff; struct ftrace_func_command *p; int ret = -EINVAL; func = strsep(&next, ":"); if (!next) { ret = ftrace_match_records(hash, func, len); if (!ret) ret = -EINVAL; if (ret < 0) return ret; return 0; } /* command found */ command = strsep(&next, ":"); mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(p->name, command) == 0) { ret = p->func(hash, func, command, next, enable); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static ssize_t ftrace_regex_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos, int enable) { struct ftrace_iterator *iter; struct trace_parser *parser; ssize_t ret, read; if (!cnt) return 0; if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; iter = m->private; } else iter = file->private_data; if (unlikely(ftrace_disabled)) return -ENODEV; /* iter->hash is a local copy, so we don't need regex_lock */ parser = &iter->parser; read = trace_get_user(parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded(parser) && !trace_parser_cont(parser)) { ret = ftrace_process_regex(iter->hash, parser->buffer, parser->idx, enable); trace_parser_clear(parser); if (ret < 0) goto out; } ret = read; out: return ret; } ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 1); } ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 0); } static int ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) { struct ftrace_func_entry *entry; if (!ftrace_location(ip)) return -EINVAL; if (remove) { entry = ftrace_lookup_ip(hash, ip); if (!entry) return -ENOENT; free_hash_entry(hash, entry); return 0; } return add_hash_entry(hash, ip); } static void ftrace_ops_update_code(struct ftrace_ops *ops, struct ftrace_ops_hash *old_hash) { struct ftrace_ops *op; if (!ftrace_enabled) return; if (ops->flags & FTRACE_OPS_FL_ENABLED) { ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); return; } /* * If this is the shared global_ops filter, then we need to * check if there is another ops that shares it, is enabled. * If so, we still need to run the modify code. */ if (ops->func_hash != &global_ops.local_hash) return; do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->func_hash == &global_ops.local_hash && op->flags & FTRACE_OPS_FL_ENABLED) { ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); /* Only need to do this once */ return; } } while_for_each_ftrace_op(op); } static int ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, unsigned long ip, int remove, int reset, int enable) { struct ftrace_hash **orig_hash; struct ftrace_ops_hash old_hash_ops; struct ftrace_hash *old_hash; struct ftrace_hash *hash; int ret; if (unlikely(ftrace_disabled)) return -ENODEV; mutex_lock(&ops->func_hash->regex_lock); if (enable) orig_hash = &ops->func_hash->filter_hash; else orig_hash = &ops->func_hash->notrace_hash; if (reset) hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); else hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); if (!hash) { ret = -ENOMEM; goto out_regex_unlock; } if (buf && !ftrace_match_records(hash, buf, len)) { ret = -EINVAL; goto out_regex_unlock; } if (ip) { ret = ftrace_match_addr(hash, ip, remove); if (ret < 0) goto out_regex_unlock; } mutex_lock(&ftrace_lock); old_hash = *orig_hash; old_hash_ops.filter_hash = ops->func_hash->filter_hash; old_hash_ops.notrace_hash = ops->func_hash->notrace_hash; ret = ftrace_hash_move(ops, enable, orig_hash, hash); if (!ret) { ftrace_ops_update_code(ops, &old_hash_ops); free_ftrace_hash_rcu(old_hash); } mutex_unlock(&ftrace_lock); out_regex_unlock: mutex_unlock(&ops->func_hash->regex_lock); free_ftrace_hash(hash); return ret; } static int ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, int reset, int enable) { return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable); } /** * ftrace_set_filter_ip - set a function to filter on in ftrace by address * @ops - the ops to set the filter with * @ip - the address to add to or remove from the filter. * @remove - non zero to remove the ip from the filter * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled * If @ip is NULL, it failes to update filter. */ int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, int remove, int reset) { ftrace_ops_init(ops); return ftrace_set_addr(ops, ip, remove, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); static int ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, int reset, int enable) { return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable); } /** * ftrace_set_filter - set a function to filter on in ftrace * @ops - the ops to set the filter with * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) { ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_filter); /** * ftrace_set_notrace - set a function to not trace in ftrace * @ops - the ops to set the notrace filter with * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) { ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 0); } EXPORT_SYMBOL_GPL(ftrace_set_notrace); /** * ftrace_set_global_filter - set a function to filter on with global tracers * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ void ftrace_set_global_filter(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_global_filter); /** * ftrace_set_global_notrace - set a function to not trace with global tracers * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 0); } EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); /* * command line interface to allow users to set filters on boot up. */ #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; /* Used by function selftest to not test if filter is set */ bool ftrace_filter_param __initdata; static int __init set_ftrace_notrace(char *str) { ftrace_filter_param = true; strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_notrace=", set_ftrace_notrace); static int __init set_ftrace_filter(char *str) { ftrace_filter_param = true; strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer); static int __init set_graph_function(char *str) { strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_filter=", set_graph_function); static int __init set_graph_notrace_function(char *str) { strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_notrace=", set_graph_notrace_function); static void __init set_ftrace_early_graph(char *buf, int enable) { int ret; char *func; unsigned long *table = ftrace_graph_funcs; int *count = &ftrace_graph_count; if (!enable) { table = ftrace_graph_notrace_funcs; count = &ftrace_graph_notrace_count; } while (buf) { func = strsep(&buf, ","); /* we allow only one expression at a time */ ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func); if (ret) printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func); } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ void __init ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable) { char *func; ftrace_ops_init(ops); while (buf) { func = strsep(&buf, ","); ftrace_set_regex(ops, func, strlen(func), 0, enable); } } static void __init set_ftrace_early_filters(void) { if (ftrace_filter_buf[0]) ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1); if (ftrace_notrace_buf[0]) ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) set_ftrace_early_graph(ftrace_graph_buf, 1); if (ftrace_graph_notrace_buf[0]) set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ } int ftrace_regex_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct ftrace_ops_hash old_hash_ops; struct ftrace_iterator *iter; struct ftrace_hash **orig_hash; struct ftrace_hash *old_hash; struct trace_parser *parser; int filter_hash; int ret; if (file->f_mode & FMODE_READ) { iter = m->private; seq_release(inode, file); } else iter = file->private_data; parser = &iter->parser; if (trace_parser_loaded(parser)) { int enable = !(iter->flags & FTRACE_ITER_NOTRACE); parser->buffer[parser->idx] = 0; ftrace_process_regex(iter->hash, parser->buffer, parser->idx, enable); } trace_parser_put(parser); mutex_lock(&iter->ops->func_hash->regex_lock); if (file->f_mode & FMODE_WRITE) { filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); if (filter_hash) orig_hash = &iter->ops->func_hash->filter_hash; else orig_hash = &iter->ops->func_hash->notrace_hash; mutex_lock(&ftrace_lock); old_hash = *orig_hash; old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash; old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash; ret = ftrace_hash_move(iter->ops, filter_hash, orig_hash, iter->hash); if (!ret) { ftrace_ops_update_code(iter->ops, &old_hash_ops); free_ftrace_hash_rcu(old_hash); } mutex_unlock(&ftrace_lock); } mutex_unlock(&iter->ops->func_hash->regex_lock); free_ftrace_hash(iter->hash); kfree(iter); return 0; } static const struct file_operations ftrace_avail_fops = { .open = ftrace_avail_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_enabled_fops = { .open = ftrace_enabled_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, .llseek = tracing_lseek, .release = ftrace_regex_release, }; static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, .llseek = tracing_lseek, .release = ftrace_regex_release, }; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static DEFINE_MUTEX(graph_lock); int ftrace_graph_count; int ftrace_graph_notrace_count; unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; struct ftrace_graph_data { unsigned long *table; size_t size; int *count; const struct seq_operations *seq_ops; }; static void * __g_next(struct seq_file *m, loff_t *pos) { struct ftrace_graph_data *fgd = m->private; if (*pos >= *fgd->count) return NULL; return &fgd->table[*pos]; } static void * g_next(struct seq_file *m, void *v, loff_t *pos) { (*pos)++; return __g_next(m, pos); } static void *g_start(struct seq_file *m, loff_t *pos) { struct ftrace_graph_data *fgd = m->private; mutex_lock(&graph_lock); /* Nothing, tell g_show to print all functions are enabled */ if (!*fgd->count && !*pos) return (void *)1; return __g_next(m, pos); } static void g_stop(struct seq_file *m, void *p) { mutex_unlock(&graph_lock); } static int g_show(struct seq_file *m, void *v) { unsigned long *ptr = v; if (!ptr) return 0; if (ptr == (unsigned long *)1) { struct ftrace_graph_data *fgd = m->private; if (fgd->table == ftrace_graph_funcs) seq_puts(m, "#### all functions enabled ####\n"); else seq_puts(m, "#### no functions disabled ####\n"); return 0; } seq_printf(m, "%ps\n", (void *)*ptr); return 0; } static const struct seq_operations ftrace_graph_seq_ops = { .start = g_start, .next = g_next, .stop = g_stop, .show = g_show, }; static int __ftrace_graph_open(struct inode *inode, struct file *file, struct ftrace_graph_data *fgd) { int ret = 0; mutex_lock(&graph_lock); if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { *fgd->count = 0; memset(fgd->table, 0, fgd->size * sizeof(*fgd->table)); } mutex_unlock(&graph_lock); if (file->f_mode & FMODE_READ) { ret = seq_open(file, fgd->seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = fgd; } } else file->private_data = fgd; return ret; } static int ftrace_graph_open(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; if (unlikely(ftrace_disabled)) return -ENODEV; fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); if (fgd == NULL) return -ENOMEM; fgd->table = ftrace_graph_funcs; fgd->size = FTRACE_GRAPH_MAX_FUNCS; fgd->count = &ftrace_graph_count; fgd->seq_ops = &ftrace_graph_seq_ops; return __ftrace_graph_open(inode, file, fgd); } static int ftrace_graph_notrace_open(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; if (unlikely(ftrace_disabled)) return -ENODEV; fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); if (fgd == NULL) return -ENOMEM; fgd->table = ftrace_graph_notrace_funcs; fgd->size = FTRACE_GRAPH_MAX_FUNCS; fgd->count = &ftrace_graph_notrace_count; fgd->seq_ops = &ftrace_graph_seq_ops; return __ftrace_graph_open(inode, file, fgd); } static int ftrace_graph_release(struct inode *inode, struct file *file) { if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; kfree(m->private); seq_release(inode, file); } else { kfree(file->private_data); } return 0; } static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer) { struct ftrace_glob func_g; struct dyn_ftrace *rec; struct ftrace_page *pg; int fail = 1; int not; bool exists; int i; /* decode regex */ func_g.type = filter_parse_regex(buffer, strlen(buffer), &func_g.search, ¬); if (!not && *idx >= size) return -EBUSY; func_g.len = strlen(func_g.search); mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) { mutex_unlock(&ftrace_lock); return -ENODEV; } do_for_each_ftrace_rec(pg, rec) { if (ftrace_match_record(rec, &func_g, NULL, 0)) { /* if it is in the array */ exists = false; for (i = 0; i < *idx; i++) { if (array[i] == rec->ip) { exists = true; break; } } if (!not) { fail = 0; if (!exists) { array[(*idx)++] = rec->ip; if (*idx >= size) goto out; } } else { if (exists) { array[i] = array[--(*idx)]; array[*idx] = 0; fail = 0; } } } } while_for_each_ftrace_rec(); out: mutex_unlock(&ftrace_lock); if (fail) return -EINVAL; return 0; } static ssize_t ftrace_graph_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_parser parser; ssize_t read, ret = 0; struct ftrace_graph_data *fgd = file->private_data; if (!cnt) return 0; if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) return -ENOMEM; read = trace_get_user(&parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded((&parser))) { parser.buffer[parser.idx] = 0; mutex_lock(&graph_lock); /* we allow only one expression at a time */ ret = ftrace_set_func(fgd->table, fgd->count, fgd->size, parser.buffer); mutex_unlock(&graph_lock); } if (!ret) ret = read; trace_parser_put(&parser); return ret; } static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, .llseek = tracing_lseek, .release = ftrace_graph_release, }; static const struct file_operations ftrace_graph_notrace_fops = { .open = ftrace_graph_notrace_open, .read = seq_read, .write = ftrace_graph_write, .llseek = tracing_lseek, .release = ftrace_graph_release, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ void ftrace_create_filter_files(struct ftrace_ops *ops, struct dentry *parent) { trace_create_file("set_ftrace_filter", 0644, parent, ops, &ftrace_filter_fops); trace_create_file("set_ftrace_notrace", 0644, parent, ops, &ftrace_notrace_fops); } /* * The name "destroy_filter_files" is really a misnomer. Although * in the future, it may actualy delete the files, but this is * really intended to make sure the ops passed in are disabled * and that when this function returns, the caller is free to * free the ops. * * The "destroy" name is only to match the "create" name that this * should be paired with. */ void ftrace_destroy_filter_files(struct ftrace_ops *ops) { mutex_lock(&ftrace_lock); if (ops->flags & FTRACE_OPS_FL_ENABLED) ftrace_shutdown(ops, 0); ops->flags |= FTRACE_OPS_FL_DELETED; ftrace_free_filter(ops); mutex_unlock(&ftrace_lock); } static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { trace_create_file("available_filter_functions", 0444, d_tracer, NULL, &ftrace_avail_fops); trace_create_file("enabled_functions", 0444, d_tracer, NULL, &ftrace_enabled_fops); ftrace_create_filter_files(&global_ops, d_tracer); #ifdef CONFIG_FUNCTION_GRAPH_TRACER trace_create_file("set_graph_function", 0444, d_tracer, NULL, &ftrace_graph_fops); trace_create_file("set_graph_notrace", 0444, d_tracer, NULL, &ftrace_graph_notrace_fops); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ return 0; } static int ftrace_cmp_ips(const void *a, const void *b) { const unsigned long *ipa = a; const unsigned long *ipb = b; if (*ipa > *ipb) return 1; if (*ipa < *ipb) return -1; return 0; } static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) { struct ftrace_page *start_pg; struct ftrace_page *pg; struct dyn_ftrace *rec; unsigned long count; unsigned long *p; unsigned long addr; unsigned long flags = 0; /* Shut up gcc */ int ret = -ENOMEM; count = end - start; if (!count) return 0; sort(start, count, sizeof(*start), ftrace_cmp_ips, NULL); start_pg = ftrace_allocate_pages(count); if (!start_pg) return -ENOMEM; mutex_lock(&ftrace_lock); /* * Core and each module needs their own pages, as * modules will free them when they are removed. * Force a new page to be allocated for modules. */ if (!mod) { WARN_ON(ftrace_pages || ftrace_pages_start); /* First initialization */ ftrace_pages = ftrace_pages_start = start_pg; } else { if (!ftrace_pages) goto out; if (WARN_ON(ftrace_pages->next)) { /* Hmm, we have free pages? */ while (ftrace_pages->next) ftrace_pages = ftrace_pages->next; } ftrace_pages->next = start_pg; } p = start; pg = start_pg; while (p < end) { addr = ftrace_call_adjust(*p++); /* * Some architecture linkers will pad between * the different mcount_loc sections of different * object files to satisfy alignments. * Skip any NULL pointers. */ if (!addr) continue; if (pg->index == pg->size) { /* We should have allocated enough */ if (WARN_ON(!pg->next)) break; pg = pg->next; } rec = &pg->records[pg->index++]; rec->ip = addr; } /* We should have used all pages */ WARN_ON(pg->next); /* Assign the last page to ftrace_pages */ ftrace_pages = pg; /* * We only need to disable interrupts on start up * because we are modifying code that an interrupt * may execute, and the modification is not atomic. * But for modules, nothing runs the code we modify * until we are finished with it, and there's no * reason to cause large interrupt latencies while we do it. */ if (!mod) local_irq_save(flags); ftrace_update_code(mod, start_pg); if (!mod) local_irq_restore(flags); ret = 0; out: mutex_unlock(&ftrace_lock); return ret; } #ifdef CONFIG_MODULES #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) void ftrace_release_mod(struct module *mod) { struct dyn_ftrace *rec; struct ftrace_page **last_pg; struct ftrace_page *pg; int order; mutex_lock(&ftrace_lock); if (ftrace_disabled) goto out_unlock; /* * Each module has its own ftrace_pages, remove * them from the list. */ last_pg = &ftrace_pages_start; for (pg = ftrace_pages_start; pg; pg = *last_pg) { rec = &pg->records[0]; if (within_module_core(rec->ip, mod)) { /* * As core pages are first, the first * page should never be a module page. */ if (WARN_ON(pg == ftrace_pages_start)) goto out_unlock; /* Check if we are deleting the last page */ if (pg == ftrace_pages) ftrace_pages = next_to_ftrace_page(last_pg); *last_pg = pg->next; order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); kfree(pg); } else last_pg = &pg->next; } out_unlock: mutex_unlock(&ftrace_lock); } static void ftrace_init_module(struct module *mod, unsigned long *start, unsigned long *end) { if (ftrace_disabled || start == end) return; ftrace_process_locs(mod, start, end); } void ftrace_module_init(struct module *mod) { ftrace_init_module(mod, mod->ftrace_callsites, mod->ftrace_callsites + mod->num_ftrace_callsites); } static int ftrace_module_notify_exit(struct notifier_block *self, unsigned long val, void *data) { struct module *mod = data; if (val == MODULE_STATE_GOING) ftrace_release_mod(mod); return 0; } #else static int ftrace_module_notify_exit(struct notifier_block *self, unsigned long val, void *data) { return 0; } #endif /* CONFIG_MODULES */ struct notifier_block ftrace_module_exit_nb = { .notifier_call = ftrace_module_notify_exit, .priority = INT_MIN, /* Run after anything that can remove kprobes */ }; void __init ftrace_init(void) { extern unsigned long __start_mcount_loc[]; extern unsigned long __stop_mcount_loc[]; unsigned long count, flags; int ret; local_irq_save(flags); ret = ftrace_dyn_arch_init(); local_irq_restore(flags); if (ret) goto failed; count = __stop_mcount_loc - __start_mcount_loc; if (!count) { pr_info("ftrace: No functions to be traced?\n"); goto failed; } pr_info("ftrace: allocating %ld entries in %ld pages\n", count, count / ENTRIES_PER_PAGE + 1); last_ftrace_enabled = ftrace_enabled = 1; ret = ftrace_process_locs(NULL, __start_mcount_loc, __stop_mcount_loc); ret = register_module_notifier(&ftrace_module_exit_nb); if (ret) pr_warning("Failed to register trace ftrace module exit notifier\n"); set_ftrace_early_filters(); return; failed: ftrace_disabled = 1; } /* Do nothing if arch does not support this */ void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) { } static void ftrace_update_trampoline(struct ftrace_ops *ops) { /* * Currently there's no safe way to free a trampoline when the kernel * is configured with PREEMPT. That is because a task could be preempted * when it jumped to the trampoline, it may be preempted for a long time * depending on the system load, and currently there's no way to know * when it will be off the trampoline. If the trampoline is freed * too early, when the task runs again, it will be executing on freed * memory and crash. */ #ifdef CONFIG_PREEMPT /* Currently, only non dynamic ops can have a trampoline */ if (ops->flags & FTRACE_OPS_FL_DYNAMIC) return; #endif arch_ftrace_update_trampoline(ops); } #else static struct ftrace_ops global_ops = { .func = ftrace_stub, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; static int __init ftrace_nodyn_init(void) { ftrace_enabled = 1; return 0; } core_initcall(ftrace_nodyn_init); static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } static inline void ftrace_startup_enable(int command) { } static inline void ftrace_startup_all(int command) { } /* Keep as macros so we do not need to define the commands */ # define ftrace_startup(ops, command) \ ({ \ int ___ret = __register_ftrace_function(ops); \ if (!___ret) \ (ops)->flags |= FTRACE_OPS_FL_ENABLED; \ ___ret; \ }) # define ftrace_shutdown(ops, command) \ ({ \ int ___ret = __unregister_ftrace_function(ops); \ if (!___ret) \ (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \ ___ret; \ }) # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) static inline int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) { return 1; } static void ftrace_update_trampoline(struct ftrace_ops *ops) { } #endif /* CONFIG_DYNAMIC_FTRACE */ __init void ftrace_init_global_array_ops(struct trace_array *tr) { tr->ops = &global_ops; tr->ops->private = tr; } void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) { /* If we filter on pids, update to use the pid function */ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { if (WARN_ON(tr->ops->func != ftrace_stub)) printk("ftrace ops had %pS for function\n", tr->ops->func); } tr->ops->func = func; tr->ops->private = tr; } void ftrace_reset_array_ops(struct trace_array *tr) { tr->ops->func = ftrace_stub; } static void ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT))) return; /* * Some of the ops may be dynamically allocated, * they must be freed after a synchronize_sched(). */ preempt_disable_notrace(); trace_recursion_set(TRACE_CONTROL_BIT); /* * Control funcs (perf) uses RCU. Only trace if * RCU is currently active. */ if (!rcu_is_watching()) goto out; do_for_each_ftrace_op(op, ftrace_control_list) { if (!(op->flags & FTRACE_OPS_FL_STUB) && !ftrace_function_local_disabled(op) && ftrace_ops_test(op, ip, regs)) op->func(ip, parent_ip, op, regs); } while_for_each_ftrace_op(op); out: trace_recursion_clear(TRACE_CONTROL_BIT); preempt_enable_notrace(); } static struct ftrace_ops control_ops = { .func = ftrace_ops_control_func, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, INIT_OPS_HASH(control_ops) }; static nokprobe_inline void __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ignored, struct pt_regs *regs) { struct ftrace_ops *op; int bit; bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; /* * Some of the ops may be dynamically allocated, * they must be freed after a synchronize_sched(). */ preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { if (ftrace_ops_test(op, ip, regs)) { if (FTRACE_WARN_ON(!op->func)) { pr_warn("op=%p %pS\n", op, op); goto out; } op->func(ip, parent_ip, op, regs); } } while_for_each_ftrace_op(op); out: preempt_enable_notrace(); trace_clear_recursion(bit); } /* * Some archs only support passing ip and parent_ip. Even though * the list function ignores the op parameter, we do not want any * C side effects, where a function is called without the caller * sending a third parameter. * Archs are to support both the regs and ftrace_ops at the same time. * If they support ftrace_ops, it is assumed they support regs. * If call backs want to use regs, they must either check for regs * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. * An architecture can pass partial regs with ftrace_ops and still * set the ARCH_SUPPORT_FTARCE_OPS. */ #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { __ftrace_ops_list_func(ip, parent_ip, NULL, regs); } NOKPROBE_SYMBOL(ftrace_ops_list_func); #else static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) { __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); } NOKPROBE_SYMBOL(ftrace_ops_no_ops); #endif /* * If there's only one function registered but it does not support * recursion, this function will be called by the mcount trampoline. * This function will handle recursion protection. */ static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { int bit; bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; op->func(ip, parent_ip, op, regs); trace_clear_recursion(bit); } NOKPROBE_SYMBOL(ftrace_ops_recurs_func); /** * ftrace_ops_get_func - get the function a trampoline should call * @ops: the ops to get the function for * * Normally the mcount trampoline will call the ops->func, but there * are times that it should not. For example, if the ops does not * have its own recursion protection, then it should call the * ftrace_ops_recurs_func() instead. * * Returns the function that the trampoline should call for @ops. */ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) { /* * If the func handles its own recursion, call it directly. * Otherwise call the recursion protected function that * will call the ftrace ops function. */ if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE)) return ftrace_ops_recurs_func; return ops->func; } static void clear_ftrace_swapper(void) { struct task_struct *p; int cpu; get_online_cpus(); for_each_online_cpu(cpu) { p = idle_task(cpu); clear_tsk_trace_trace(p); } put_online_cpus(); } static void set_ftrace_swapper(void) { struct task_struct *p; int cpu; get_online_cpus(); for_each_online_cpu(cpu) { p = idle_task(cpu); set_tsk_trace_trace(p); } put_online_cpus(); } static void clear_ftrace_pid(struct pid *pid) { struct task_struct *p; rcu_read_lock(); do_each_pid_task(pid, PIDTYPE_PID, p) { clear_tsk_trace_trace(p); } while_each_pid_task(pid, PIDTYPE_PID, p); rcu_read_unlock(); put_pid(pid); } static void set_ftrace_pid(struct pid *pid) { struct task_struct *p; rcu_read_lock(); do_each_pid_task(pid, PIDTYPE_PID, p) { set_tsk_trace_trace(p); } while_each_pid_task(pid, PIDTYPE_PID, p); rcu_read_unlock(); } static void clear_ftrace_pid_task(struct pid *pid) { if (pid == ftrace_swapper_pid) clear_ftrace_swapper(); else clear_ftrace_pid(pid); } static void set_ftrace_pid_task(struct pid *pid) { if (pid == ftrace_swapper_pid) set_ftrace_swapper(); else set_ftrace_pid(pid); } static int ftrace_pid_add(int p) { struct pid *pid; struct ftrace_pid *fpid; int ret = -EINVAL; mutex_lock(&ftrace_lock); if (!p) pid = ftrace_swapper_pid; else pid = find_get_pid(p); if (!pid) goto out; ret = 0; list_for_each_entry(fpid, &ftrace_pids, list) if (fpid->pid == pid) goto out_put; ret = -ENOMEM; fpid = kmalloc(sizeof(*fpid), GFP_KERNEL); if (!fpid) goto out_put; list_add(&fpid->list, &ftrace_pids); fpid->pid = pid; set_ftrace_pid_task(pid); ftrace_update_pid_func(); ftrace_startup_all(0); mutex_unlock(&ftrace_lock); return 0; out_put: if (pid != ftrace_swapper_pid) put_pid(pid); out: mutex_unlock(&ftrace_lock); return ret; } static void ftrace_pid_reset(void) { struct ftrace_pid *fpid, *safe; mutex_lock(&ftrace_lock); list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) { struct pid *pid = fpid->pid; clear_ftrace_pid_task(pid); list_del(&fpid->list); kfree(fpid); } ftrace_update_pid_func(); ftrace_startup_all(0); mutex_unlock(&ftrace_lock); } static void *fpid_start(struct seq_file *m, loff_t *pos) { mutex_lock(&ftrace_lock); if (!ftrace_pids_enabled() && (!*pos)) return (void *) 1; return seq_list_start(&ftrace_pids, *pos); } static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) { if (v == (void *)1) return NULL; return seq_list_next(v, &ftrace_pids, pos); } static void fpid_stop(struct seq_file *m, void *p) { mutex_unlock(&ftrace_lock); } static int fpid_show(struct seq_file *m, void *v) { const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list); if (v == (void *)1) { seq_puts(m, "no pid\n"); return 0; } if (fpid->pid == ftrace_swapper_pid) seq_puts(m, "swapper tasks\n"); else seq_printf(m, "%u\n", pid_vnr(fpid->pid)); return 0; } static const struct seq_operations ftrace_pid_sops = { .start = fpid_start, .next = fpid_next, .stop = fpid_stop, .show = fpid_show, }; static int ftrace_pid_open(struct inode *inode, struct file *file) { int ret = 0; if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) ftrace_pid_reset(); if (file->f_mode & FMODE_READ) ret = seq_open(file, &ftrace_pid_sops); return ret; } static ssize_t ftrace_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64], *tmp; long val; int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; /* * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid" * to clean the filter quietly. */ tmp = strstrip(buf); if (strlen(tmp) == 0) return 1; ret = kstrtol(tmp, 10, &val); if (ret < 0) return ret; ret = ftrace_pid_add(val); return ret ? ret : cnt; } static int ftrace_pid_release(struct inode *inode, struct file *file) { if (file->f_mode & FMODE_READ) seq_release(inode, file); return 0; } static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, .llseek = tracing_lseek, .release = ftrace_pid_release, }; static __init int ftrace_init_tracefs(void) { struct dentry *d_tracer; d_tracer = tracing_init_dentry(); if (IS_ERR(d_tracer)) return 0; ftrace_init_dyn_tracefs(d_tracer); trace_create_file("set_ftrace_pid", 0644, d_tracer, NULL, &ftrace_pid_fops); ftrace_profile_tracefs(d_tracer); return 0; } fs_initcall(ftrace_init_tracefs); /** * ftrace_kill - kill ftrace * * This function should be used by panic code. It stops ftrace * but in a not so nice way. If you need to simply kill ftrace * from a non-atomic section, use ftrace_kill. */ void ftrace_kill(void) { ftrace_disabled = 1; ftrace_enabled = 0; clear_ftrace_function(); } /** * Test if ftrace is dead or not. */ int ftrace_is_dead(void) { return ftrace_disabled; } /** * register_ftrace_function - register a function for profiling * @ops - ops structure that holds the function for profiling. * * Register a function to be called by all functions in the * kernel. * * Note: @ops->func and all the functions it calls must be labeled * with "notrace", otherwise it will go into a * recursive loop. */ int register_ftrace_function(struct ftrace_ops *ops) { int ret = -1; ftrace_ops_init(ops); mutex_lock(&ftrace_lock); ret = ftrace_startup(ops, 0); mutex_unlock(&ftrace_lock); return ret; } EXPORT_SYMBOL_GPL(register_ftrace_function); /** * unregister_ftrace_function - unregister a function for profiling. * @ops - ops structure that holds the function to unregister * * Unregister a function that was added to be called by ftrace profiling. */ int unregister_ftrace_function(struct ftrace_ops *ops) { int ret; mutex_lock(&ftrace_lock); ret = ftrace_shutdown(ops, 0); mutex_unlock(&ftrace_lock); return ret; } EXPORT_SYMBOL_GPL(unregister_ftrace_function); int ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret = -ENODEV; mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) goto out; ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; last_ftrace_enabled = !!ftrace_enabled; if (ftrace_enabled) { /* we are starting ftrace again */ if (ftrace_ops_list != &ftrace_list_end) update_ftrace_function(); ftrace_startup_sysctl(); } else { /* stopping ftrace calls (just send to ftrace_stub) */ ftrace_trace_function = ftrace_stub; ftrace_shutdown_sysctl(); } out: mutex_unlock(&ftrace_lock); return ret; } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static struct ftrace_ops graph_ops = { .func = ftrace_stub, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID | FTRACE_OPS_FL_STUB, #ifdef FTRACE_GRAPH_TRAMP_ADDR .trampoline = FTRACE_GRAPH_TRAMP_ADDR, /* trampoline_size is only needed for dynamically allocated tramps */ #endif ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash) }; void ftrace_graph_sleep_time_control(bool enable) { fgraph_sleep_time = enable; } void ftrace_graph_graph_time_control(bool enable) { fgraph_graph_time = enable; } int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) { return 0; } /* The callbacks that hook a function */ trace_func_graph_ret_t ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub; /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) { int i; int ret = 0; unsigned long flags; int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; struct task_struct *g, *t; for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); if (!ret_stack_list[i]) { start = 0; end = i; ret = -ENOMEM; goto free; } } read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { if (start == end) { ret = -EAGAIN; goto unlock; } if (t->ret_stack == NULL) { atomic_set(&t->trace_overrun, 0); t->curr_ret_stack = -1; /* Make sure the tasks see the -1 first: */ smp_wmb(); t->ret_stack = ret_stack_list[start++]; } } while_each_thread(g, t); unlock: read_unlock_irqrestore(&tasklist_lock, flags); free: for (i = start; i < end; i++) kfree(ret_stack_list[i]); return ret; } static void ftrace_graph_probe_sched_switch(void *ignore, bool preempt, struct task_struct *prev, struct task_struct *next) { unsigned long long timestamp; int index; /* * Does the user want to count the time a function was asleep. * If so, do not update the time stamps. */ if (fgraph_sleep_time) return; timestamp = trace_clock_local(); prev->ftrace_timestamp = timestamp; /* only process tasks that we timestamped */ if (!next->ftrace_timestamp) return; /* * Update all the counters in next to make up for the * time next was sleeping. */ timestamp -= next->ftrace_timestamp; for (index = next->curr_ret_stack; index >= 0; index--) next->ret_stack[index].calltime += timestamp; } /* Allocate a return stack for each task */ static int start_graph_tracing(void) { struct ftrace_ret_stack **ret_stack_list; int ret, cpu; ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * sizeof(struct ftrace_ret_stack *), GFP_KERNEL); if (!ret_stack_list) return -ENOMEM; /* The cpu_boot init_task->ret_stack will never be freed */ for_each_online_cpu(cpu) { if (!idle_task(cpu)->ret_stack) ftrace_graph_init_idle_task(idle_task(cpu), cpu); } do { ret = alloc_retstack_tasklist(ret_stack_list); } while (ret == -EAGAIN); if (!ret) { ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); if (ret) pr_info("ftrace_graph: Couldn't activate tracepoint" " probe to kernel_sched_switch\n"); } kfree(ret_stack_list); return ret; } /* * Hibernation protection. * The state of the current task is too much unstable during * suspend/restore to disk. We want to protect against that. */ static int ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, void *unused) { switch (state) { case PM_HIBERNATION_PREPARE: pause_graph_tracing(); break; case PM_POST_HIBERNATION: unpause_graph_tracing(); break; } return NOTIFY_DONE; } static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) { if (!ftrace_ops_test(&global_ops, trace->func, NULL)) return 0; return __ftrace_graph_entry(trace); } /* * The function graph tracer should only trace the functions defined * by set_ftrace_filter and set_ftrace_notrace. If another function * tracer ops is registered, the graph tracer requires testing the * function against the global ops, and not just trace any function * that any ftrace_ops registered. */ static void update_function_graph_func(void) { struct ftrace_ops *op; bool do_test = false; /* * The graph and global ops share the same set of functions * to test. If any other ops is on the list, then * the graph tracing needs to test if its the function * it should call. */ do_for_each_ftrace_op(op, ftrace_ops_list) { if (op != &global_ops && op != &graph_ops && op != &ftrace_list_end) { do_test = true; /* in double loop, break out with goto */ goto out; } } while_for_each_ftrace_op(op); out: if (do_test) ftrace_graph_entry = ftrace_graph_entry_test; else ftrace_graph_entry = __ftrace_graph_entry; } static struct notifier_block ftrace_suspend_notifier = { .notifier_call = ftrace_suspend_notifier_call, }; int register_ftrace_graph(trace_func_graph_ret_t retfunc, trace_func_graph_ent_t entryfunc) { int ret = 0; mutex_lock(&ftrace_lock); /* we currently allow only one tracer registered at a time */ if (ftrace_graph_active) { ret = -EBUSY; goto out; } register_pm_notifier(&ftrace_suspend_notifier); ftrace_graph_active++; ret = start_graph_tracing(); if (ret) { ftrace_graph_active--; goto out; } ftrace_graph_return = retfunc; /* * Update the indirect function to the entryfunc, and the * function that gets called to the entry_test first. Then * call the update fgraph entry function to determine if * the entryfunc should be called directly or not. */ __ftrace_graph_entry = entryfunc; ftrace_graph_entry = ftrace_graph_entry_test; update_function_graph_func(); ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); out: mutex_unlock(&ftrace_lock); return ret; } void unregister_ftrace_graph(void) { mutex_lock(&ftrace_lock); if (unlikely(!ftrace_graph_active)) goto out; ftrace_graph_active--; ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; ftrace_graph_entry = ftrace_graph_entry_stub; __ftrace_graph_entry = ftrace_graph_entry_stub; ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); out: mutex_unlock(&ftrace_lock); } static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); static void graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) { atomic_set(&t->trace_overrun, 0); t->ftrace_timestamp = 0; /* make curr_ret_stack visible before we add the ret_stack */ smp_wmb(); t->ret_stack = ret_stack; } /* * Allocate a return stack for the idle task. May be the first * time through, or it may be done by CPU hotplug online. */ void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { t->curr_ret_stack = -1; /* * The idle task has no parent, it either has its own * stack or no stack at all. */ if (t->ret_stack) WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu)); if (ftrace_graph_active) { struct ftrace_ret_stack *ret_stack; ret_stack = per_cpu(idle_ret_stack, cpu); if (!ret_stack) { ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); if (!ret_stack) return; per_cpu(idle_ret_stack, cpu) = ret_stack; } graph_init_task(t, ret_stack); } } /* Allocate a return stack for newly created task */ void ftrace_graph_init_task(struct task_struct *t) { /* Make sure we do not use the parent ret_stack */ t->ret_stack = NULL; t->curr_ret_stack = -1; if (ftrace_graph_active) { struct ftrace_ret_stack *ret_stack; ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); if (!ret_stack) return; graph_init_task(t, ret_stack); } } void ftrace_graph_exit_task(struct task_struct *t) { struct ftrace_ret_stack *ret_stack = t->ret_stack; t->ret_stack = NULL; /* NULL must become visible to IRQs before we free it: */ barrier(); kfree(ret_stack); } #endif