summaryrefslogtreecommitdiff
path: root/arch/s390/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/mm/fault.c')
-rw-r--r--arch/s390/mm/fault.c249
1 files changed, 137 insertions, 112 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index ab988135e5c6..fe103e891e7a 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -34,7 +34,7 @@
#include <asm/asm-offsets.h>
#include <asm/system.h>
#include <asm/pgtable.h>
-#include <asm/s390_ext.h>
+#include <asm/irq.h>
#include <asm/mmu_context.h>
#include <asm/compat.h>
#include "../kernel/entry.h"
@@ -225,33 +225,6 @@ static noinline void do_sigbus(struct pt_regs *regs, long int_code,
force_sig_info(SIGBUS, &si, tsk);
}
-#ifdef CONFIG_S390_EXEC_PROTECT
-static noinline int signal_return(struct pt_regs *regs, long int_code,
- unsigned long trans_exc_code)
-{
- u16 instruction;
- int rc;
-
- rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
-
- if (!rc && instruction == 0x0a77) {
- clear_tsk_thread_flag(current, TIF_PER_TRAP);
- if (is_compat_task())
- sys32_sigreturn();
- else
- sys_sigreturn();
- } else if (!rc && instruction == 0x0aad) {
- clear_tsk_thread_flag(current, TIF_PER_TRAP);
- if (is_compat_task())
- sys32_rt_sigreturn();
- else
- sys_rt_sigreturn();
- } else
- do_sigsegv(regs, int_code, SEGV_MAPERR, trans_exc_code);
- return 0;
-}
-#endif /* CONFIG_S390_EXEC_PROTECT */
-
static noinline void do_fault_error(struct pt_regs *regs, long int_code,
unsigned long trans_exc_code, int fault)
{
@@ -259,13 +232,6 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code,
switch (fault) {
case VM_FAULT_BADACCESS:
-#ifdef CONFIG_S390_EXEC_PROTECT
- if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
- (trans_exc_code & 3) == 0) {
- signal_return(regs, int_code, trans_exc_code);
- break;
- }
-#endif /* CONFIG_S390_EXEC_PROTECT */
case VM_FAULT_BADMAP:
/* Bad memory access. Check if it is kernel or user space. */
if (regs->psw.mask & PSW_MASK_PSTATE) {
@@ -279,9 +245,12 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code,
do_no_context(regs, int_code, trans_exc_code);
break;
default: /* fault & VM_FAULT_ERROR */
- if (fault & VM_FAULT_OOM)
- pagefault_out_of_memory();
- else if (fault & VM_FAULT_SIGBUS) {
+ if (fault & VM_FAULT_OOM) {
+ if (!(regs->psw.mask & PSW_MASK_PSTATE))
+ do_no_context(regs, int_code, trans_exc_code);
+ else
+ pagefault_out_of_memory();
+ } else if (fault & VM_FAULT_SIGBUS) {
/* Kernel mode? Handle exceptions or die */
if (!(regs->psw.mask & PSW_MASK_PSTATE))
do_no_context(regs, int_code, trans_exc_code);
@@ -311,7 +280,8 @@ static inline int do_exception(struct pt_regs *regs, int access,
struct mm_struct *mm;
struct vm_area_struct *vma;
unsigned long address;
- int fault, write;
+ unsigned int flags;
+ int fault;
if (notify_page_fault(regs))
return 0;
@@ -330,6 +300,10 @@ static inline int do_exception(struct pt_regs *regs, int access,
address = trans_exc_code & __FAIL_ADDR_MASK;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
+ flags = FAULT_FLAG_ALLOW_RETRY;
+ if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)
+ flags |= FAULT_FLAG_WRITE;
+retry:
down_read(&mm->mmap_sem);
fault = VM_FAULT_BADMAP;
@@ -359,21 +333,31 @@ static inline int do_exception(struct pt_regs *regs, int access,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- write = (access == VM_WRITE ||
- (trans_exc_code & store_indication) == 0x400) ?
- FAULT_FLAG_WRITE : 0;
- fault = handle_mm_fault(mm, vma, address, write);
+ fault = handle_mm_fault(mm, vma, address, flags);
if (unlikely(fault & VM_FAULT_ERROR))
goto out_up;
- if (fault & VM_FAULT_MAJOR) {
- tsk->maj_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
- regs, address);
- } else {
- tsk->min_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
- regs, address);
+ /*
+ * Major/minor page fault accounting is only done on the
+ * initial attempt. If we go through a retry, it is extremely
+ * likely that the page will be found in page cache at that point.
+ */
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR) {
+ tsk->maj_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
+ regs, address);
+ } else {
+ tsk->min_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
+ regs, address);
+ }
+ if (fault & VM_FAULT_RETRY) {
+ /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
+ * of starvation. */
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ goto retry;
+ }
}
/*
* The instruction that caused the program check will
@@ -414,11 +398,6 @@ void __kprobes do_dat_exception(struct pt_regs *regs, long pgm_int_code,
int access, fault;
access = VM_READ | VM_EXEC | VM_WRITE;
-#ifdef CONFIG_S390_EXEC_PROTECT
- if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
- (trans_exc_code & 3) == 0)
- access = VM_EXEC;
-#endif
fault = do_exception(regs, access, trans_exc_code);
if (unlikely(fault))
do_fault_error(regs, pgm_int_code & 255, trans_exc_code, fault);
@@ -468,10 +447,9 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write)
access = write ? VM_WRITE : VM_READ;
fault = do_exception(&regs, access, uaddr | 2);
if (unlikely(fault)) {
- if (fault & VM_FAULT_OOM) {
- pagefault_out_of_memory();
- fault = 0;
- } else if (fault & VM_FAULT_SIGBUS)
+ if (fault & VM_FAULT_OOM)
+ return -EFAULT;
+ else if (fault & VM_FAULT_SIGBUS)
do_sigbus(&regs, pgm_int_code, uaddr);
}
return fault ? -EFAULT : 0;
@@ -491,22 +469,28 @@ static int __init nopfault(char *str)
__setup("nopfault", nopfault);
-typedef struct {
- __u16 refdiagc;
- __u16 reffcode;
- __u16 refdwlen;
- __u16 refversn;
- __u64 refgaddr;
- __u64 refselmk;
- __u64 refcmpmk;
- __u64 reserved;
-} __attribute__ ((packed, aligned(8))) pfault_refbk_t;
+struct pfault_refbk {
+ u16 refdiagc;
+ u16 reffcode;
+ u16 refdwlen;
+ u16 refversn;
+ u64 refgaddr;
+ u64 refselmk;
+ u64 refcmpmk;
+ u64 reserved;
+} __attribute__ ((packed, aligned(8)));
int pfault_init(void)
{
- pfault_refbk_t refbk =
- { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48,
- __PF_RES_FIELD };
+ struct pfault_refbk refbk = {
+ .refdiagc = 0x258,
+ .reffcode = 0,
+ .refdwlen = 5,
+ .refversn = 2,
+ .refgaddr = __LC_CURRENT_PID,
+ .refselmk = 1ULL << 48,
+ .refcmpmk = 1ULL << 48,
+ .reserved = __PF_RES_FIELD };
int rc;
if (!MACHINE_IS_VM || pfault_disable)
@@ -518,18 +502,20 @@ int pfault_init(void)
"2:\n"
EX_TABLE(0b,1b)
: "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc");
- __ctl_set_bit(0, 9);
return rc;
}
void pfault_fini(void)
{
- pfault_refbk_t refbk =
- { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL };
+ struct pfault_refbk refbk = {
+ .refdiagc = 0x258,
+ .reffcode = 1,
+ .refdwlen = 5,
+ .refversn = 2,
+ };
if (!MACHINE_IS_VM || pfault_disable)
return;
- __ctl_clear_bit(0,9);
asm volatile(
" diag %0,0,0x258\n"
"0:\n"
@@ -537,11 +523,15 @@ void pfault_fini(void)
: : "a" (&refbk), "m" (refbk) : "cc");
}
+static DEFINE_SPINLOCK(pfault_lock);
+static LIST_HEAD(pfault_list);
+
static void pfault_interrupt(unsigned int ext_int_code,
unsigned int param32, unsigned long param64)
{
struct task_struct *tsk;
__u16 subcode;
+ pid_t pid;
/*
* Get the external interruption subcode & pfault
@@ -553,44 +543,79 @@ static void pfault_interrupt(unsigned int ext_int_code,
if ((subcode & 0xff00) != __SUBCODE_MASK)
return;
kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
-
- /*
- * Get the token (= address of the task structure of the affected task).
- */
-#ifdef CONFIG_64BIT
- tsk = (struct task_struct *) param64;
-#else
- tsk = (struct task_struct *) param32;
-#endif
-
+ if (subcode & 0x0080) {
+ /* Get the token (= pid of the affected task). */
+ pid = sizeof(void *) == 4 ? param32 : param64;
+ rcu_read_lock();
+ tsk = find_task_by_pid_ns(pid, &init_pid_ns);
+ if (tsk)
+ get_task_struct(tsk);
+ rcu_read_unlock();
+ if (!tsk)
+ return;
+ } else {
+ tsk = current;
+ }
+ spin_lock(&pfault_lock);
if (subcode & 0x0080) {
/* signal bit is set -> a page has been swapped in by VM */
- if (xchg(&tsk->thread.pfault_wait, -1) != 0) {
+ if (tsk->thread.pfault_wait == 1) {
/* Initial interrupt was faster than the completion
* interrupt. pfault_wait is valid. Set pfault_wait
* back to zero and wake up the process. This can
* safely be done because the task is still sleeping
* and can't produce new pfaults. */
tsk->thread.pfault_wait = 0;
+ list_del(&tsk->thread.list);
wake_up_process(tsk);
- put_task_struct(tsk);
+ } else {
+ /* Completion interrupt was faster than initial
+ * interrupt. Set pfault_wait to -1 so the initial
+ * interrupt doesn't put the task to sleep. */
+ tsk->thread.pfault_wait = -1;
}
+ put_task_struct(tsk);
} else {
/* signal bit not set -> a real page is missing. */
- get_task_struct(tsk);
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- if (xchg(&tsk->thread.pfault_wait, 1) != 0) {
+ if (tsk->thread.pfault_wait == -1) {
/* Completion interrupt was faster than the initial
- * interrupt (swapped in a -1 for pfault_wait). Set
- * pfault_wait back to zero and exit. This can be
- * done safely because tsk is running in kernel
- * mode and can't produce new pfaults. */
+ * interrupt (pfault_wait == -1). Set pfault_wait
+ * back to zero and exit. */
tsk->thread.pfault_wait = 0;
- set_task_state(tsk, TASK_RUNNING);
- put_task_struct(tsk);
- } else
+ } else {
+ /* Initial interrupt arrived before completion
+ * interrupt. Let the task sleep. */
+ tsk->thread.pfault_wait = 1;
+ list_add(&tsk->thread.list, &pfault_list);
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
set_tsk_need_resched(tsk);
+ }
+ }
+ spin_unlock(&pfault_lock);
+}
+
+static int __cpuinit pfault_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct thread_struct *thread, *next;
+ struct task_struct *tsk;
+
+ switch (action) {
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ spin_lock_irq(&pfault_lock);
+ list_for_each_entry_safe(thread, next, &pfault_list, list) {
+ thread->pfault_wait = 0;
+ list_del(&thread->list);
+ tsk = container_of(thread, struct task_struct, thread);
+ wake_up_process(tsk);
+ }
+ spin_unlock_irq(&pfault_lock);
+ break;
+ default:
+ break;
}
+ return NOTIFY_OK;
}
static int __init pfault_irq_init(void)
@@ -599,22 +624,22 @@ static int __init pfault_irq_init(void)
if (!MACHINE_IS_VM)
return 0;
- /*
- * Try to get pfault pseudo page faults going.
- */
rc = register_external_interrupt(0x2603, pfault_interrupt);
- if (rc) {
- pfault_disable = 1;
- return rc;
- }
- if (pfault_init() == 0)
- return 0;
+ if (rc)
+ goto out_extint;
+ rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
+ if (rc)
+ goto out_pfault;
+ service_subclass_irq_register();
+ hotcpu_notifier(pfault_cpu_notify, 0);
+ return 0;
- /* Tough luck, no pfault. */
- pfault_disable = 1;
+out_pfault:
unregister_external_interrupt(0x2603, pfault_interrupt);
- return 0;
+out_extint:
+ pfault_disable = 1;
+ return rc;
}
early_initcall(pfault_irq_init);
-#endif
+#endif /* CONFIG_PFAULT */
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-14 03:03:40 +0000