sysrq: Document hexadecimal values for kernel.sysrq bitmask
It makes more sense to enter a bitmask in hexadecimal rather than
decimal. Sadly we can't make it read back as hexadecimal.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index 8cb4d78..1c0471d 100644
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -20,18 +20,21 @@
1 - enable all functions of sysrq
>1 - bitmask of allowed sysrq functions (see below for detailed function
description):
- 2 - enable control of console logging level
- 4 - enable control of keyboard (SAK, unraw)
- 8 - enable debugging dumps of processes etc.
- 16 - enable sync command
- 32 - enable remount read-only
- 64 - enable signalling of processes (term, kill, oom-kill)
- 128 - allow reboot/poweroff
- 256 - allow nicing of all RT tasks
+ 2 = 0x2 - enable control of console logging level
+ 4 = 0x4 - enable control of keyboard (SAK, unraw)
+ 8 = 0x8 - enable debugging dumps of processes etc.
+ 16 = 0x10 - enable sync command
+ 32 = 0x20 - enable remount read-only
+ 64 = 0x40 - enable signalling of processes (term, kill, oom-kill)
+ 128 = 0x80 - allow reboot/poweroff
+ 256 = 0x100 - allow nicing of all RT tasks
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.
+
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
allowed (by a user with admin privileges).