diff options
| -rw-r--r-- | Documentation/sysrq.txt | 13 | ||||
| -rw-r--r-- | drivers/tty/sysrq.c | 2 | ||||
| -rw-r--r-- | include/linux/sysrq.h | 3 | ||||
| -rw-r--r-- | kernel/sysctl.c | 2 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 9 |
5 files changed, 17 insertions, 12 deletions
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 1c0471dc70fe..0e307c94809a 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -11,11 +11,9 @@ regardless of whatever else it is doing, unless it is completely locked up. You need to say "yes" to 'Magic SysRq key (CONFIG_MAGIC_SYSRQ)' when configuring the kernel. When running a kernel with SysRq compiled in, /proc/sys/kernel/sysrq controls the functions allowed to be invoked via -the SysRq key. By default the file contains 1 which means that every -possible SysRq request is allowed (in older versions SysRq was disabled -by default, and you were required to specifically enable it at run-time -but this is not the case any more). Here is the list of possible values -in /proc/sys/kernel/sysrq: +the SysRq key. The default value in this file is set by the +CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE config symbol, which itself defaults +to 1. Here is the list of possible values in /proc/sys/kernel/sysrq: 0 - disable sysrq completely 1 - enable all functions of sysrq >1 - bitmask of allowed sysrq functions (see below for detailed function @@ -32,8 +30,9 @@ in /proc/sys/kernel/sysrq: You can set the value in the file by the following command: echo "number" >/proc/sys/kernel/sysrq -The number may be written either as decimal or as hexadecimal with the -0x prefix. +The number may be written here either as decimal or as hexadecimal +with the 0x prefix. CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE must always be +written in hexadecimal. Note that the value of /proc/sys/kernel/sysrq influences only the invocation via a keyboard. Invocation of any operation via /proc/sysrq-trigger is always diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 40a9fe9d3b10..ce396ecdf412 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -51,7 +51,7 @@ #include <asm/irq_regs.h> /* Whether we react on sysrq keys or just ignore them */ -static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; +static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; static bool __read_mostly sysrq_always_enabled; unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED }; diff --git a/include/linux/sysrq.h b/include/linux/sysrq.h index 7faf933cced7..387fa7d05c98 100644 --- a/include/linux/sysrq.h +++ b/include/linux/sysrq.h @@ -17,9 +17,6 @@ #include <linux/errno.h> #include <linux/types.h> -/* Enable/disable SYSRQ support by default (0==no, 1==yes). */ -#define SYSRQ_DEFAULT_ENABLE 1 - /* Possible values of bitmask for enabling sysrq functions */ /* 0x0001 is reserved for enable everything */ #define SYSRQ_ENABLE_LOG 0x0002 diff --git a/kernel/sysctl.c b/kernel/sysctl.c index b2f06f3c6a3f..8b80f1bae21a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -190,7 +190,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write, #ifdef CONFIG_MAGIC_SYSRQ /* Note: sysrq code uses it's own private copy */ -static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE; +static int __sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; static int sysrq_sysctl_handler(ctl_table *table, int write, void __user *buffer, size_t *lenp, diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 06344d986eb9..29329374ff0d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -312,6 +312,15 @@ config MAGIC_SYSRQ keys are documented in <file:Documentation/sysrq.txt>. Don't say Y unless you really know what this hack does. +config MAGIC_SYSRQ_DEFAULT_ENABLE + hex "Enable magic SysRq key functions by default" + depends on MAGIC_SYSRQ + default 0x1 + help + Specifies which SysRq key functions are enabled by default. + This may be set to 1 or 0 to enable or disable them all, or + to a bitmask as described in Documentation/sysrq.txt. + config DEBUG_KERNEL bool "Kernel debugging" help |