[PATCH AUTOSEL 6.11 066/244] drivers/perf: arm_spe: Use perf_allow_kernel() for permissions
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STALE736d
From: Sasha Levin <sashal@kernel.org>
Date: 2024-09-25 11:39:19
Also in:
linux-perf-users, lkml, stable
Subsystem:
arm pmu profiling and debugging, performance events subsystem, the rest · Maintainers:
Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: James Clark <james.clark@linaro.org> [ Upstream commit 5e9629d0ae977d6f6916d7e519724804e95f0b07 ] Use perf_allow_kernel() for 'pa_enable' (physical addresses), 'pct_enable' (physical timestamps) and context IDs. This means that perf_event_paranoid is now taken into account and LSM hooks can be used, which is more consistent with other perf_event_open calls. For example PERF_SAMPLE_PHYS_ADDR uses perf_allow_kernel() rather than just perfmon_capable(). This also indirectly fixes the following error message which is misleading because perf_event_paranoid is not taken into account by perfmon_capable(): $ perf record -e arm_spe/pa_enable/ Error: Access to performance monitoring and observability operations is limited. Consider adjusting /proc/sys/kernel/perf_event_paranoid setting ... Suggested-by: Al Grant <redacted> Signed-off-by: James Clark <james.clark@linaro.org> Link: https://lore.kernel.org/r/20240827145113.1224604-1-james.clark@linaro.org (local) Link: https://lore.kernel.org/all/20240807120039.GD37996@noisy.programming.kicks-ass.net/ (local) Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/perf/arm_spe_pmu.c | 9 ++++----- include/linux/perf_event.h | 8 +------- kernel/events/core.c | 9 +++++++++ 3 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 9100d82bfabc0..3569050f9cf37 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c@@ -41,7 +41,7 @@ /* * Cache if the event is allowed to trace Context information. - * This allows us to perform the check, i.e, perfmon_capable(), + * This allows us to perform the check, i.e, perf_allow_kernel(), * in the context of the event owner, once, during the event_init(). */ #define SPE_PMU_HW_FLAGS_CX 0x00001
@@ -50,7 +50,7 @@ static_assert((PERF_EVENT_FLAG_ARCH & SPE_PMU_HW_FLAGS_CX) == SPE_PMU_HW_FLAGS_C static void set_spe_event_has_cx(struct perf_event *event) { - if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && perfmon_capable()) + if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && !perf_allow_kernel(&event->attr)) event->hw.flags |= SPE_PMU_HW_FLAGS_CX; }
@@ -745,9 +745,8 @@ static int arm_spe_pmu_event_init(struct perf_event *event) set_spe_event_has_cx(event); reg = arm_spe_event_to_pmscr(event); - if (!perfmon_capable() && - (reg & (PMSCR_EL1_PA | PMSCR_EL1_PCT))) - return -EACCES; + if (reg & (PMSCR_EL1_PA | PMSCR_EL1_PCT)) + return perf_allow_kernel(&event->attr); return 0; }
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 1a8942277ddad..e336306b8c08e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h@@ -1602,13 +1602,7 @@ static inline int perf_is_paranoid(void) return sysctl_perf_event_paranoid > -1; } -static inline int perf_allow_kernel(struct perf_event_attr *attr) -{ - if (sysctl_perf_event_paranoid > 1 && !perfmon_capable()) - return -EACCES; - - return security_perf_event_open(attr, PERF_SECURITY_KERNEL); -} +int perf_allow_kernel(struct perf_event_attr *attr); static inline int perf_allow_cpu(struct perf_event_attr *attr) {
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8a6c6bbcd658a..b21c8f24a9876 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c@@ -13358,6 +13358,15 @@ const struct perf_event_attr *perf_event_attrs(struct perf_event *event) return &event->attr; } +int perf_allow_kernel(struct perf_event_attr *attr) +{ + if (sysctl_perf_event_paranoid > 1 && !perfmon_capable()) + return -EACCES; + + return security_perf_event_open(attr, PERF_SECURITY_KERNEL); +} +EXPORT_SYMBOL_GPL(perf_allow_kernel); + /* * Inherit an event from parent task to child task. *
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2.43.0