diff options
author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2015-01-14 14:18:20 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2015-04-02 17:14:19 +0200 |
commit | 4807034248bed58d49a4f9f450c024e3b0f58577 (patch) | |
tree | f5d76d32a1046852d6748d9405c3706910a1d1d6 /arch/x86/kernel/cpu/perf_event.c | |
parent | ed69628b3b04578179334393d7f5fe60a2681f1c (diff) |
perf/x86: Mark Intel PT and LBR/BTS as mutually exclusive
Intel PT cannot be used at the same time as LBR or BTS and will cause a
general protection fault if they are used together. In order to avoid
fixing up GPs in the fast path, instead we disallow creating LBR/BTS
events when PT events are present and vice versa.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-12-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
-rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 0420ebcac116..549d01d6d996 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -263,6 +263,14 @@ static void hw_perf_event_destroy(struct perf_event *event) } } +void hw_perf_lbr_event_destroy(struct perf_event *event) +{ + hw_perf_event_destroy(event); + + /* undo the lbr/bts event accounting */ + x86_del_exclusive(x86_lbr_exclusive_lbr); +} + static inline int x86_pmu_initialized(void) { return x86_pmu.handle_irq != NULL; @@ -302,6 +310,35 @@ set_ext_hw_attr(struct hw_perf_event *hwc, struct perf_event *event) return x86_pmu_extra_regs(val, event); } +/* + * Check if we can create event of a certain type (that no conflicting events + * are present). + */ +int x86_add_exclusive(unsigned int what) +{ + int ret = -EBUSY, i; + + if (atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what])) + return 0; + + mutex_lock(&pmc_reserve_mutex); + for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++) + if (i != what && atomic_read(&x86_pmu.lbr_exclusive[i])) + goto out; + + atomic_inc(&x86_pmu.lbr_exclusive[what]); + ret = 0; + +out: + mutex_unlock(&pmc_reserve_mutex); + return ret; +} + +void x86_del_exclusive(unsigned int what) +{ + atomic_dec(&x86_pmu.lbr_exclusive[what]); +} + int x86_setup_perfctr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; @@ -346,6 +383,12 @@ int x86_setup_perfctr(struct perf_event *event) /* BTS is currently only allowed for user-mode. */ if (!attr->exclude_kernel) return -EOPNOTSUPP; + + /* disallow bts if conflicting events are present */ + if (x86_add_exclusive(x86_lbr_exclusive_lbr)) + return -EBUSY; + + event->destroy = hw_perf_lbr_event_destroy; } hwc->config |= config; |