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@xxxxxxxxxxxxx> --- 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); }