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generic, x86: add prctl commands PR_GET_TSC and PR_SET_TSC 

This patch adds prctl commands that make it possible
to deny the execution of timestamp counters in userspace.
If this is not implemented on a specific architecture,
prctl will return -EINVAL.

ned-off-by: Erik Bosman <ejbosman@cs.vu.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Erik Bosman 2008-04-11 18:54:17 +02:00 committed by Ingo Molnar
parent 5deb45e39b
commit 8fb402bccf
2 changed files with 18 additions and 1 deletions
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6
include/linux/prctl.h
View File

@ -67,4 +67,10 @@
#define PR_CAPBSET_READ 23
#define PR_CAPBSET_DROP 24
/* Get/set the process' ability to use the timestamp counter instruction */
#define PR_GET_TSC 25
#define PR_SET_TSC 26
# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
#endif /* _LINUX_PRCTL_H */

13
kernel/sys.c
View File

@ -67,6 +67,12 @@
#ifndef SET_ENDIAN
# define SET_ENDIAN(a,b) (-EINVAL)
#endif
#ifndef GET_TSC_CTL
# define GET_TSC_CTL(a) (-EINVAL)
#endif
#ifndef SET_TSC_CTL
# define SET_TSC_CTL(a) (-EINVAL)
#endif
/*
* this is where the system-wide overflow UID and GID are defined, for
@ -1737,7 +1743,12 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
#else
return -EINVAL;
#endif
case PR_GET_TSC:
error = GET_TSC_CTL(arg2);
break;
case PR_SET_TSC:
error = SET_TSC_CTL(arg2);
break;
default:
error = -EINVAL;
break;