generic, x86: add prctl commands PR_GET_TSC and PR_SET_TSC
authorErik Bosman <ebn310@few.vu.nl>
Fri, 11 Apr 2008 16:54:17 +0000 (18:54 +0200)
committerIngo Molnar <mingo@elte.hu>
Sat, 19 Apr 2008 17:19:55 +0000 (19:19 +0200)
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>
include/linux/prctl.h
kernel/sys.c

index 3800639775aee4706734b1aa9bb3e55104fe4f3b..5c80b1939636ec556f775692aa5ed27aba5986b4 100644 (file)
 #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 */
index a626116af5db96b58f47434eb47c6af23da6535e..6a0cc71ee88d61e1afdd47e960a841515dad8a3c 100644 (file)
 #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;