linux-kernel - [tip: sched/core] x86/perf/amd: Remove tracing from perf_lopwr

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Message-ID: <167361307678.4906.7808954024859813192.tip-bot2@tip-bot2>
Date:   Fri, 13 Jan 2023 12:31:16 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Frederic Weisbecker <frederic@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/core] x86/perf/amd: Remove tracing from perf_lopwr_cb()

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     1f7c232ee080f01ded1236685a357f8926e8c7d5
Gitweb:        https://git.kernel.org/tip/1f7c232ee080f01ded1236685a357f8926e8c7d5
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Thu, 12 Jan 2023 20:43:15 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 13 Jan 2023 11:03:21 +01:00

x86/perf/amd: Remove tracing from perf_lopwr_cb()

The perf_lopwr_cb() function is called from the idle routines; there
is no RCU there, we must not enter tracing.

Use __always_inline, noidle annotations and existing no-trace methods.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Tony Lindgren <tony@...mide.com>
Tested-by: Ulf Hansson <ulf.hansson@...aro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20230112195539.392862891@infradead.org
---
 arch/x86/events/amd/brs.c         | 13 +++++--------
 arch/x86/include/asm/perf_event.h |  2 +-
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/x86/events/amd/brs.c b/arch/x86/events/amd/brs.c
index 58461fa..ed30871 100644
--- a/arch/x86/events/amd/brs.c
+++ b/arch/x86/events/amd/brs.c
@@ -41,18 +41,15 @@ static inline unsigned int brs_to(int idx)
 	return MSR_AMD_SAMP_BR_FROM + 2 * idx + 1;
 }
 
-static inline void set_debug_extn_cfg(u64 val)
+static __always_inline void set_debug_extn_cfg(u64 val)
 {
 	/* bits[4:3] must always be set to 11b */
-	wrmsrl(MSR_AMD_DBG_EXTN_CFG, val | 3ULL << 3);
+	__wrmsr(MSR_AMD_DBG_EXTN_CFG, val | 3ULL << 3, val >> 32);
 }
 
-static inline u64 get_debug_extn_cfg(void)
+static __always_inline u64 get_debug_extn_cfg(void)
 {
-	u64 val;
-
-	rdmsrl(MSR_AMD_DBG_EXTN_CFG, val);
-	return val;
+	return __rdmsr(MSR_AMD_DBG_EXTN_CFG);
 }
 
 static bool __init amd_brs_detect(void)
@@ -405,7 +402,7 @@ void amd_pmu_brs_sched_task(struct perf_event_pmu_context *pmu_ctx, bool sched_i
  * called from ACPI processor_idle.c or acpi_pad.c
  * with interrupts disabled
  */
-void perf_amd_brs_lopwr_cb(bool lopwr_in)
+void noinstr perf_amd_brs_lopwr_cb(bool lopwr_in)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	union amd_debug_extn_cfg cfg;
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 5d0f689..76e7924 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -578,7 +578,7 @@ extern void perf_amd_brs_lopwr_cb(bool lopwr_in);
 
 DECLARE_STATIC_CALL(perf_lopwr_cb, perf_amd_brs_lopwr_cb);
 
-static inline void perf_lopwr_cb(bool lopwr_in)
+static __always_inline void perf_lopwr_cb(bool lopwr_in)
 {
 	static_call_mod(perf_lopwr_cb)(lopwr_in);
 }