perf_counter: sysctl for system wide perf counters

Impact: add sysctl for paranoid/relaxed perfcounters policy

Allow the use of system wide perf counters to everybody, but provide
a sysctl to disable it for the paranoid security minded.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090409085524.514046352@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4286b62b34a0..8ba457838d95 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -49,6 +49,7 @@
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
 #include <linux/slow-work.h>
+#include <linux/perf_counter.h>
 
 #include <asm/uaccess.h>
 #include <asm/processor.h>
@@ -920,6 +921,16 @@ static struct ctl_table kern_table[] = {
                 .child          = slow_work_sysctls,
         },
 #endif
+#ifdef CONFIG_PERF_COUNTERS
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "perf_counter_privileged",
+                .data           = &sysctl_perf_counter_priv,
+                .maxlen         = sizeof(sysctl_perf_counter_priv),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
+#endif
 /*
  * NOTE: do not add new entries to this table unless you have read
  * Documentation/sysctl/ctl_unnumbered.txt