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>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index 3800639775ae..5c80b1939636 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 */