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perf/x86: Disable extended registers for non-supported PMUs 

The perf fuzzer caused Skylake machine to crash:

[ 9680.085831] Call Trace:
[ 9680.088301]  <IRQ>
[ 9680.090363]  perf_output_sample_regs+0x43/0xa0
[ 9680.094928]  perf_output_sample+0x3aa/0x7a0
[ 9680.099181]  perf_event_output_forward+0x53/0x80
[ 9680.103917]  __perf_event_overflow+0x52/0xf0
[ 9680.108266]  ? perf_trace_run_bpf_submit+0xc0/0xc0
[ 9680.113108]  perf_swevent_hrtimer+0xe2/0x150
[ 9680.117475]  ? check_preempt_wakeup+0x181/0x230
[ 9680.122091]  ? check_preempt_curr+0x62/0x90
[ 9680.126361]  ? ttwu_do_wakeup+0x19/0x140
[ 9680.130355]  ? try_to_wake_up+0x54/0x460
[ 9680.134366]  ? reweight_entity+0x15b/0x1a0
[ 9680.138559]  ? __queue_work+0x103/0x3f0
[ 9680.142472]  ? update_dl_rq_load_avg+0x1cd/0x270
[ 9680.147194]  ? timerqueue_del+0x1e/0x40
[ 9680.151092]  ? __remove_hrtimer+0x35/0x70
[ 9680.155191]  __hrtimer_run_queues+0x100/0x280
[ 9680.159658]  hrtimer_interrupt+0x100/0x220
[ 9680.163835]  smp_apic_timer_interrupt+0x6a/0x140
[ 9680.168555]  apic_timer_interrupt+0xf/0x20
[ 9680.172756]  </IRQ>

The XMM registers can only be collected by PEBS hardware events on the
platforms with PEBS baseline support, e.g. Icelake, not software/probe
events.

Add capabilities flag PERF_PMU_CAP_EXTENDED_REGS to indicate the PMU
which support extended registers. For X86, the extended registers are
XMM registers.

Add has_extended_regs() to check if extended registers are applied.

The generic code define the mask of extended registers as 0 if arch
headers haven't overridden it.

Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 878068ea27 ("perf/x86: Support outputting XMM registers")
Link: https://lkml.kernel.org/r/1559081314-9714-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kan Liang 2019-05-28 15:08:30 -07:00 committed by Ingo Molnar
parent 913a90bc5a
commit e321d02db8
5 changed files with 27 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/events/intel/ds.c
View File

@ -2020,6 +2020,7 @@ void __init intel_ds_init(void)
PERF_SAMPLE_TIME;
x86_pmu.flags |= PMU_FL_PEBS_ALL;
pebs_qual = "-baseline";
x86_get_pmu()->capabilities |= PERF_PMU_CAP_EXTENDED_REGS;
} else {
/* Only basic record supported */
x86_pmu.pebs_no_xmm_regs = 1;

3
arch/x86/include/uapi/asm/perf_regs.h
View File

@ -52,4 +52,7 @@ enum perf_event_x86_regs {
/* These include both GPRs and XMMX registers */
PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2,
};
#define PERF_REG_EXTENDED_MASK (~((1ULL << PERF_REG_X86_XMM0) - 1))
#endif /* _ASM_X86_PERF_REGS_H */

1
include/linux/perf_event.h
View File

@ -241,6 +241,7 @@ struct perf_event;
#define PERF_PMU_CAP_NO_INTERRUPT 0x01
#define PERF_PMU_CAP_NO_NMI 0x02
#define PERF_PMU_CAP_AUX_NO_SG 0x04
#define PERF_PMU_CAP_EXTENDED_REGS 0x08
#define PERF_PMU_CAP_EXCLUSIVE 0x10
#define PERF_PMU_CAP_ITRACE 0x20
#define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40

8
include/linux/perf_regs.h
View File

@ -11,6 +11,11 @@ struct perf_regs {
#ifdef CONFIG_HAVE_PERF_REGS
#include <asm/perf_regs.h>
#ifndef PERF_REG_EXTENDED_MASK
#define PERF_REG_EXTENDED_MASK 0
#endif
u64 perf_reg_value(struct pt_regs *regs, int idx);
int perf_reg_validate(u64 mask);
u64 perf_reg_abi(struct task_struct *task);
@ -18,6 +23,9 @@ void perf_get_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs,
struct pt_regs *regs_user_copy);
#else
#define PERF_REG_EXTENDED_MASK 0
static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
{
return 0;

18
kernel/events/core.c
View File

@ -10036,6 +10036,12 @@ void perf_pmu_unregister(struct pmu *pmu)
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
static inline bool has_extended_regs(struct perf_event *event)
{
return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
(event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
}
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
struct perf_event_context *ctx = NULL;
@ -10067,12 +10073,16 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
perf_event_ctx_unlock(event->group_leader, ctx);
if (!ret) {
if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
has_extended_regs(event))
ret = -EOPNOTSUPP;
if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
event_has_any_exclude_flag(event)) {
if (event->destroy)
event->destroy(event);
event_has_any_exclude_flag(event))
ret = -EINVAL;
}
if (ret && event->destroy)
event->destroy(event);
}
if (ret)