[tip:perfcounters/core] perf_counter: x86: Allow unpriviliged use of NMIs

tip-bot for Peter Zijlstra
2009-05-15T08:45:47Z

Commit-ID: a026dfecc035f213c1cfa0bf6407ce3155f6a9df
Gitweb: http://git.kernel.org/tip/a026dfecc035f213c1cfa0bf6407ce3155f6a9df
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Wed, 13 May 2009 10:02:57 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 15 May 2009 09:46:57 +0200

perf_counter: x86: Allow unpriviliged use of NMIs

Apply sysctl_perf_counter_priv to NMIs. Also, fail the counter
creation instead of silently down-grading to regular interrupts.

[ Impact: allow wider perf-counter usage ]

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: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/kernel/cpu/perf_counter.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 88ae8ce..c19e927 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -280,8 +280,11 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
* If privileged enough, allow NMI events:
*/
hwc->nmi = 0;
- if (capable(CAP_SYS_ADMIN) && hw_event->nmi)
+ if (hw_event->nmi) {
+ if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
hwc->nmi = 1;
+ }

hwc->irq_period = hw_event->irq_period;
if ((s64)hwc->irq_period <= 0 || hwc->irq_period > x86_pmu.max_period)