We must prohibit the CPU from tracing before we disable the TRBE and only re-enable it when we are sure the TRBE has been enabled back. Otherwise, leave the CPU in prohibited state.
Cc: Anshuman Khandual anshuman.khandual@arm.com Cc: Mathieu Poirier mathieu.poirier@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Leo Yan leo.yan@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com --- .../hwtracing/coresight/coresight-self-hosted-trace.h | 4 +++- drivers/hwtracing/coresight/coresight-trbe.c | 9 +++++++++ 2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h index 586d26e0cba3..34372482a3cd 100644 --- a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h +++ b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h @@ -22,11 +22,13 @@ static inline void write_trfcr(u64 val) isb(); }
-static inline void cpu_prohibit_trace(void) +static inline u64 cpu_prohibit_trace(void) { u64 trfcr = read_trfcr();
/* Prohibit tracing at EL0 & the kernel EL */ write_trfcr(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE)); + /* Return the original value of the TRFCR */ + return trfcr; } #endif /* __CORESIGHT_SELF_HOSTED_TRACE_H */ diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index e7567727e8fc..b8586c170889 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -16,6 +16,7 @@ #define pr_fmt(fmt) DRVNAME ": " fmt
#include <asm/barrier.h> +#include "coresight-self-hosted-trace.h" #include "coresight-trbe.h"
#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT)) @@ -764,6 +765,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) enum trbe_fault_action act; u64 status; bool truncated = false; + u64 trfcr;
/* Reads to TRBSR_EL1 is fine when TRBE is active */ status = read_sysreg_s(SYS_TRBSR_EL1); @@ -774,6 +776,8 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) if (!is_trbe_irq(status)) return IRQ_NONE;
+ /* Prohibit the CPU from tracing before we disable the TRBE */ + trfcr = cpu_prohibit_trace(); /* * Ensure the trace is visible to the CPUs and * any external aborts have been resolved. @@ -805,9 +809,14 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) /* * If the buffer was truncated, ensure perf callbacks * have completed, which will disable the event. + * + * Otherwise, restore the trace filter controls to + * allow the tracing. */ if (truncated) irq_work_run(); + else + write_trfcr(trfcr);
return IRQ_HANDLED; }