Messages in this thread Patch in this message | | | Date | Fri, 11 Apr 2008 18:54:17 +0200 (CEST) | From | Erik Bosman <> | Subject | [PATCH 1/3] 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.
Signed-off-by: Erik Bosman <ejbosman@cs.vu.nl> --- include/linux/prctl.h | 6 ++++++ kernel/sys.c | 13 ++++++++++++- 2 files changed, 18 insertions(+), 1 deletions(-)
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;
| |