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| author | Ingo Molnar <mingo@elte.hu> | 2006-12-13 00:34:36 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-13 09:05:50 -0800 |
| commit | 5d6f647fc6bb57377c9f417c4752e43189f56bb1 (patch) | |
| tree | ab30c24c021adc549aab6bf042108d920975d9a9 /drivers/char/sysrq.c | |
| parent | e61c90188b9956edae1105eef361d8981a352fcd (diff) | |
| download | linux-5d6f647fc6bb57377c9f417c4752e43189f56bb1.tar.gz linux-5d6f647fc6bb57377c9f417c4752e43189f56bb1.tar.bz2 linux-5d6f647fc6bb57377c9f417c4752e43189f56bb1.zip | |
[PATCH] debug: add sysrq_always_enabled boot option
Most distributions enable sysrq support but set it to 0 by default. Add a
sysrq_always_enabled boot option to always-enable sysrq keys. Useful for
debugging - without having to modify the disribution's config files (which
might not be possible if the kernel is on a live CD, etc.).
Also, while at it, clean up the sysrq interfaces.
[bunk@stusta.de: make sysrq_always_enabled_setup() static]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/char/sysrq.c')
| -rw-r--r-- | drivers/char/sysrq.c | 37 |
1 files changed, 31 insertions, 6 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index 05810c8d20bc..13935235e066 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -41,7 +41,34 @@ #include <asm/irq_regs.h> /* Whether we react on sysrq keys or just ignore them */ -int sysrq_enabled = 1; +int __read_mostly __sysrq_enabled = 1; + +static int __read_mostly sysrq_always_enabled; + +int sysrq_on(void) +{ + return __sysrq_enabled || sysrq_always_enabled; +} + +/* + * A value of 1 means 'all', other nonzero values are an op mask: + */ +static inline int sysrq_on_mask(int mask) +{ + return sysrq_always_enabled || __sysrq_enabled == 1 || + (__sysrq_enabled & mask); +} + +static int __init sysrq_always_enabled_setup(char *str) +{ + sysrq_always_enabled = 1; + printk(KERN_INFO "debug: sysrq always enabled.\n"); + + return 1; +} + +__setup("sysrq_always_enabled", sysrq_always_enabled_setup); + static void sysrq_handle_loglevel(int key, struct tty_struct *tty) { @@ -379,8 +406,7 @@ void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) * Should we check for enabled operations (/proc/sysrq-trigger * should not) and is the invoked operation enabled? */ - if (!check_mask || sysrq_enabled == 1 || - (sysrq_enabled & op_p->enable_mask)) { + if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { printk("%s\n", op_p->action_msg); console_loglevel = orig_log_level; op_p->handler(key, tty); @@ -414,9 +440,8 @@ void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) */ void handle_sysrq(int key, struct tty_struct *tty) { - if (!sysrq_enabled) - return; - __handle_sysrq(key, tty, 1); + if (sysrq_on()) + __handle_sysrq(key, tty, 1); } EXPORT_SYMBOL(handle_sysrq); |