From fd89cfb8718753459fcea3fe6103d19de5e86c9b Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 6 Aug 2010 16:11:01 +0200 Subject: Dynamic Debug: Split out query string parsing/setup from proc_write The parsing and applying of dynamic debug strings is not only useful for /sys/../dynamic_debug/control write access, but can also be used for boot parameter parsing. The boot parameter is introduced in a follow up patch. Signed-off-by: Thomas Renninger Acked-by: jbaron@redhat.com Acked-by: Pekka Enberg Signed-off-by: Greg Kroah-Hartman --- lib/dynamic_debug.c | 40 +++++++++++++++++++++++++--------------- 1 file changed, 25 insertions(+), 15 deletions(-) (limited to 'lib/dynamic_debug.c') diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 02afc2533728..84d103c474e4 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -429,6 +429,27 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp, return 0; } +static int ddebug_exec_query(char *query_string) +{ + unsigned int flags = 0, mask = 0; + struct ddebug_query query; +#define MAXWORDS 9 + int nwords; + char *words[MAXWORDS]; + + nwords = ddebug_tokenize(query_string, words, MAXWORDS); + if (nwords <= 0) + return -EINVAL; + if (ddebug_parse_query(words, nwords-1, &query)) + return -EINVAL; + if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) + return -EINVAL; + + /* actually go and implement the change */ + ddebug_change(&query, flags, mask); + return 0; +} + /* * File_ops->write method for /dynamic_debug/conrol. Gathers the * command text from userspace, parses and executes it. @@ -436,12 +457,8 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp, static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf, size_t len, loff_t *offp) { - unsigned int flags = 0, mask = 0; - struct ddebug_query query; -#define MAXWORDS 9 - int nwords; - char *words[MAXWORDS]; char tmpbuf[256]; + int ret; if (len == 0) return 0; @@ -455,16 +472,9 @@ static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf, printk(KERN_INFO "%s: read %d bytes from userspace\n", __func__, (int)len); - nwords = ddebug_tokenize(tmpbuf, words, MAXWORDS); - if (nwords <= 0) - return -EINVAL; - if (ddebug_parse_query(words, nwords-1, &query)) - return -EINVAL; - if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) - return -EINVAL; - - /* actually go and implement the change */ - ddebug_change(&query, flags, mask); + ret = ddebug_exec_query(tmpbuf); + if (ret) + return ret; *offp += len; return len; -- cgit v1.2.3 From a648ec05bb950fae2f35d0490ddd6cf15010af72 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 6 Aug 2010 16:11:02 +0200 Subject: Dynamic Debug: Introduce ddebug_query= boot parameter Dynamic debug lacks the ability to enable debug messages at boot time. One could patch initramfs or service startup scripts to write to /sys/../dynamic_debug/control, but this sucks. This patch makes it possible to pass a query in the same format one can write to /sys/../dynamic_debug/control via boot param. When dynamic debug gets initialized, this query will automatically be applied. Signed-off-by: Thomas Renninger Acked-by: jbaron@redhat.com Acked-by: Pekka Enberg Signed-off-by: Greg Kroah-Hartman --- lib/dynamic_debug.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'lib/dynamic_debug.c') diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 84d103c474e4..44ce66bdb211 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -450,6 +450,19 @@ static int ddebug_exec_query(char *query_string) return 0; } +static __initdata char ddebug_setup_string[1024]; +static __init int ddebug_setup_query(char *str) +{ + if (strlen(str) >= 1024) { + pr_warning("ddebug boot param string too large\n"); + return 0; + } + strcpy(ddebug_setup_string, str); + return 1; +} + +__setup("ddebug_query=", ddebug_setup_query); + /* * File_ops->write method for /dynamic_debug/conrol. Gathers the * command text from userspace, parses and executes it. @@ -769,6 +782,18 @@ static int __init dynamic_debug_init(void) } ret = ddebug_add_module(iter_start, n, modname); } + + /* ddebug_query boot param got passed -> set it up */ + if (ddebug_setup_string[0] != '\0') { + ret = ddebug_exec_query(ddebug_setup_string); + if (ret) + pr_warning("Invalid ddebug boot param %s", + ddebug_setup_string); + else + pr_info("ddebug initialized with string %s", + ddebug_setup_string); + } + out_free: if (ret) { ddebug_remove_all_tables(); -- cgit v1.2.3 From 6a5c083de2f5fbf89a4b0a251be2c2205434d7ea Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 6 Aug 2010 16:11:03 +0200 Subject: Dynamic Debug: Initialize dynamic debug earlier via arch_initcall Having the ddebug_query= boot parameter it makes sense to set up dynamic debug as soon as possible. I expect sysfs files cannot be set up via an arch_initcall, because this one is even before fs_initcall. Therefore I splitted the dynamic_debug_init function into an early one and a later one providing /sys/../dynamic_debug/control file. Possibly dynamic_debug can be initialized even earlier, not sure whether this still makes sense then. I picked up arch_initcall as it covers quite a lot already. Dynamic debug needs to allocate memory, therefore it's not easily possible to set it up even before the command line gets parsed. Therefore the boot param query string is stored in a temp string which is applied when dynamic debug gets set up. This has been tested with ddebug_query="file ec.c +p" and I could retrieve pr_debug() messages early at boot during ACPI setup: ACPI: EC: Look up EC in DSDT ACPI: EC: ---> status = 0x08 ACPI: EC: transaction start ACPI: EC: <--- command = 0x80 ACPI: EC: ~~~> interrupt ACPI: EC: ---> status = 0x08 ACPI: EC: <--- data = 0xa4 ... ACPI: Interpreter enabled ACPI: (supports S0 S3 S4 S5) ACPI: Using IOAPIC for interrupt routing ACPI: EC: ---> status = 0x00 ACPI: EC: transaction start ACPI: EC: <--- command = 0x80 Signed-off-by: Thomas Renninger Acked-by: jbaron@redhat.com Acked-by: Pekka Enberg CC: linux-acpi@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- lib/dynamic_debug.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) (limited to 'lib/dynamic_debug.c') diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 44ce66bdb211..a687d902daab 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -748,13 +748,14 @@ static void ddebug_remove_all_tables(void) mutex_unlock(&ddebug_lock); } -static int __init dynamic_debug_init(void) +static __initdata int ddebug_init_success; + +static int __init dynamic_debug_init_debugfs(void) { struct dentry *dir, *file; - struct _ddebug *iter, *iter_start; - const char *modname = NULL; - int ret = 0; - int n = 0; + + if (!ddebug_init_success) + return -ENODEV; dir = debugfs_create_dir("dynamic_debug", NULL); if (!dir) @@ -765,6 +766,16 @@ static int __init dynamic_debug_init(void) debugfs_remove(dir); return -ENOMEM; } + return 0; +} + +static int __init dynamic_debug_init(void) +{ + struct _ddebug *iter, *iter_start; + const char *modname = NULL; + int ret = 0; + int n = 0; + if (__start___verbose != __stop___verbose) { iter = __start___verbose; modname = iter->modname; @@ -795,11 +806,13 @@ static int __init dynamic_debug_init(void) } out_free: - if (ret) { + if (ret) ddebug_remove_all_tables(); - debugfs_remove(dir); - debugfs_remove(file); - } + else + ddebug_init_success = 1; return 0; } -module_init(dynamic_debug_init); +/* Allow early initialization for boot messages via boot param */ +arch_initcall(dynamic_debug_init); +/* Debugfs setup must be done later */ +module_init(dynamic_debug_init_debugfs); -- cgit v1.2.3