The spec for ID_DFR0_EL1 says "In an AArch64-only implementation, this register is UNKNOWN." Indeed ThunderX just returns zero when that register is read. This means we can't rely on a non-zero value to determine if we can test the PMU. For AArch64 we need to read ID_AA64DFR0_EL1. This patch has the side effect of no longer running PMU tests on TCG for AArch64. That's actually another fix, though, as TCG chooses not to implement a PMU for AArch64 at this time. The only way it worked before was probing the wrong register and proceeding even though the version was 2, which is not a valid version for AArch64. When TCG eventually implements a PMU things should "just work".
Signed-off-by: Andrew Jones <[email protected]> --- arm/pmu.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/arm/pmu.c b/arm/pmu.c index a39dae43c99e..c4d5c97dbf87 100644 --- a/arm/pmu.c +++ b/arm/pmu.c @@ -28,15 +28,15 @@ #define PMU_PMCR_IMP_SHIFT 24 #define PMU_PMCR_IMP_MASK 0xff -#define ID_DFR0_PERFMON_SHIFT 24 -#define ID_DFR0_PERFMON_MASK 0xf - -#define PMU_CYCLE_IDX 31 +#define PMU_CYCLE_IDX 31 #define NR_SAMPLES 10 static unsigned int pmu_version; #if defined(__arm__) +#define ID_DFR0_PERFMON_SHIFT 24 +#define ID_DFR0_PERFMON_MASK 0xf + #define PMCR __ACCESS_CP15(c9, 0, c12, 0) #define ID_DFR0 __ACCESS_CP15(c0, 0, c1, 2) #define PMSELR __ACCESS_CP15(c9, 0, c12, 5) @@ -50,6 +50,11 @@ static inline uint32_t get_pmcr(void) { return read_sysreg(PMCR); } static inline void set_pmcr(uint32_t v) { write_sysreg(v, PMCR); } static inline void set_pmcntenset(uint32_t v) { write_sysreg(v, PMCNTENSET); } +static inline uint8_t get_pmu_version(void) +{ + return (get_id_dfr0() >> ID_DFR0_PERFMON_SHIFT) & ID_DFR0_PERFMON_MASK; +} + static inline uint64_t get_pmccntr(void) { if (pmu_version == 0x3) @@ -95,7 +100,10 @@ static inline void precise_instrs_loop(int loop, uint32_t pmcr) : "cc"); } #elif defined(__aarch64__) -static inline uint32_t get_id_dfr0(void) { return read_sysreg(id_dfr0_el1); } +#define ID_AA64DFR0_PERFMON_SHIFT 8 +#define ID_AA64DFR0_PERFMON_MASK 0xf + +static inline uint32_t get_id_aa64dfr0(void) { return read_sysreg(id_aa64dfr0_el1); } static inline uint32_t get_pmcr(void) { return read_sysreg(pmcr_el0); } static inline void set_pmcr(uint32_t v) { write_sysreg(v, pmcr_el0); } static inline uint64_t get_pmccntr(void) { return read_sysreg(pmccntr_el0); } @@ -103,6 +111,12 @@ static inline void set_pmccntr(uint64_t v) { write_sysreg(v, pmccntr_el0); } static inline void set_pmcntenset(uint32_t v) { write_sysreg(v, pmcntenset_el0); } static inline void set_pmccfiltr(uint32_t v) { write_sysreg(v, pmccfiltr_el0); } +static inline uint8_t get_pmu_version(void) +{ + uint8_t ver = (get_id_aa64dfr0() >> ID_AA64DFR0_PERFMON_SHIFT) & ID_AA64DFR0_PERFMON_MASK; + return ver == 1 ? 3 : ver; +} + /* * Extra instructions inserted by the compiler would be difficult to compensate * for, so hand assemble everything between, and including, the PMCR accesses @@ -256,16 +270,9 @@ static bool check_cpi(int cpi) /* Return FALSE if no PMU found, otherwise return TRUE */ bool pmu_probe(void) { - uint32_t dfr0; - - /* probe pmu version */ - dfr0 = get_id_dfr0(); - pmu_version = (dfr0 >> ID_DFR0_PERFMON_SHIFT) & ID_DFR0_PERFMON_MASK; - - if (pmu_version) - report_info("PMU version: %d", pmu_version); - - return pmu_version; + pmu_version = get_pmu_version(); + report_info("PMU version: %d", pmu_version); + return pmu_version != 0 && pmu_version != 0xf; } int main(int argc, char *argv[]) -- 2.9.3 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
