diff options
Diffstat (limited to 'drivers/char/sysrq.c')
| -rw-r--r-- | drivers/char/sysrq.c | 57 |
1 files changed, 42 insertions, 15 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index 05810c8d20b..7fd3cd5ddf2 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) { @@ -188,7 +215,7 @@ static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty) } static struct sysrq_key_op sysrq_showstate_blocked_op = { .handler = sysrq_handle_showstate_blocked, - .help_msg = "showBlockedTasks", + .help_msg = "shoW-blocked-tasks", .action_msg = "Show Blocked State", .enable_mask = SYSRQ_ENABLE_DUMP, }; @@ -288,15 +315,16 @@ static struct sysrq_key_op *sysrq_key_table[36] = { &sysrq_loglevel_op, /* 9 */ /* - * Don't use for system provided sysrqs, it is handled specially on - * sparc and will never arrive + * a: Don't use for system provided sysrqs, it is handled specially on + * sparc and will never arrive. */ NULL, /* a */ &sysrq_reboot_op, /* b */ - &sysrq_crashdump_op, /* c */ + &sysrq_crashdump_op, /* c & ibm_emac driver debug */ &sysrq_showlocks_op, /* d */ &sysrq_term_op, /* e */ &sysrq_moom_op, /* f */ + /* g: May be registered by ppc for kgdb */ NULL, /* g */ NULL, /* h */ &sysrq_kill_op, /* i */ @@ -305,18 +333,19 @@ static struct sysrq_key_op *sysrq_key_table[36] = { NULL, /* l */ &sysrq_showmem_op, /* m */ &sysrq_unrt_op, /* n */ - /* This will often be registered as 'Off' at init time */ + /* o: This will often be registered as 'Off' at init time */ NULL, /* o */ &sysrq_showregs_op, /* p */ NULL, /* q */ - &sysrq_unraw_op, /* r */ + &sysrq_unraw_op, /* r */ &sysrq_sync_op, /* s */ &sysrq_showstate_op, /* t */ &sysrq_mountro_op, /* u */ - /* May be assigned at init time by SMP VOYAGER */ + /* v: May be registered at init time by SMP VOYAGER */ NULL, /* v */ - NULL, /* w */ - &sysrq_showstate_blocked_op, /* x */ + &sysrq_showstate_blocked_op, /* w */ + /* x: May be registered on ppc/powerpc for xmon */ + NULL, /* x */ NULL, /* y */ NULL /* z */ }; @@ -379,8 +408,7 @@ 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 +442,8 @@ 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); |