[PATCH 01/36] x86/perf/amd: Remove tracing from perf_lopwr_cb()

Peter Zijlstra
2022-06-08T14:27:24Z

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/events/amd/brs.c | 13 +++++--------
arch/x86/include/asm/perf_event.h | 2 +-
2 files changed, 6 insertions(+), 9 deletions(-)

--- 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 id
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)
@@ -338,7 +335,7 @@ void amd_pmu_brs_sched_task(struct perf_
* 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;
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -554,7 +554,7 @@ extern void perf_amd_brs_lopwr_cb(bool l

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);
}