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 <drjones@xxxxxxxxxx>
---
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
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
