From: Erik Bosman Date: Fri, 11 Apr 2008 16:54:17 +0000 (+0200) Subject: generic, x86: add prctl commands PR_GET_TSC and PR_SET_TSC X-Git-Tag: v2.6.26-rc1~1133^2~62 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=8fb402bccf203ecca8f9e0202b8fd3c937dece6f 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/include/linux/prctl.h b/include/linux/prctl.h index 3800639..5c80b19 100644 --- a/include/linux/prctl.h +++ b/include/linux/prctl.h @@ -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 */ diff --git a/kernel/sys.c b/kernel/sys.c index a626116..6a0cc71 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -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;