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perf/arm_pmuv3: Add PMUv3.9 per counter EL0 access control

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Armv8.9/9.4 PMUv3.9 adds per counter EL0 access controls. Per counter
access is enabled with the UEN bit in PMUSERENR_EL1 register. Individual
counters are enabled/disabled in the PMUACR_EL1 register. When UEN is
set, the CR/ER bits control EL0 write access and must be set to disable
write access.

With the access controls, the clearing of unused counters can be
skipped.

KVM also configures PMUSERENR_EL1 in order to trap to EL2. UEN does not
need to be set for it since only PMUv3.5 is exposed to guests.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20241002184326.1105499-1-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Rob Herring (Arm) 2024-10-02 13:43:24 -05:00 committed by Will Deacon
parent 759b5fc6cc
commit 0bbff9ed81
5 changed files with 44 additions and 10 deletions
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6
arch/arm/include/asm/arm_pmuv3.h
View File

@ -231,6 +231,7 @@ static inline void kvm_vcpu_pmu_resync_el0(void) {}
#define ARMV8_PMU_DFR_VER_V3P1 0x4
#define ARMV8_PMU_DFR_VER_V3P4 0x5
#define ARMV8_PMU_DFR_VER_V3P5 0x6
#define ARMV8_PMU_DFR_VER_V3P9 0x9
#define ARMV8_PMU_DFR_VER_IMP_DEF 0xF
static inline bool pmuv3_implemented(int pmuver)
@ -249,6 +250,11 @@ static inline bool is_pmuv3p5(int pmuver)
return pmuver >= ARMV8_PMU_DFR_VER_V3P5;
}
static inline bool is_pmuv3p9(int pmuver)
{
return pmuver >= ARMV8_PMU_DFR_VER_V3P9;
}
static inline u64 read_pmceid0(void)
{
u64 val = read_sysreg(PMCEID0);

10
arch/arm64/include/asm/arm_pmuv3.h
View File

@ -152,6 +152,11 @@ static inline void write_pmuserenr(u32 val)
write_sysreg(val, pmuserenr_el0);
}
static inline void write_pmuacr(u64 val)
{
write_sysreg_s(val, SYS_PMUACR_EL1);
}
static inline u64 read_pmceid0(void)
{
return read_sysreg(pmceid0_el0);
@ -178,4 +183,9 @@ static inline bool is_pmuv3p5(int pmuver)
return pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P5;
}
static inline bool is_pmuv3p9(int pmuver)
{
return pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P9;
}
#endif

8
arch/arm64/tools/sysreg
View File

@ -1238,6 +1238,7 @@ UnsignedEnum 11:8 PMUVer
0b0110 V3P5
0b0111 V3P7
0b1000 V3P8
0b1001 V3P9
0b1111 IMP_DEF
EndEnum
UnsignedEnum 7:4 TraceVer
@ -2178,6 +2179,13 @@ Field 4 P
Field 3:0 ALIGN
EndSysreg
Sysreg PMUACR_EL1 3 0 9 14 4
Res0 63:33
Field 32 F0
Field 31 C
Field 30:0 P
EndSysreg
Sysreg PMSELR_EL0 3 3 9 12 5
Res0 63:5
Field 4:0 SEL

29
drivers/perf/arm_pmuv3.c
View File

@ -770,18 +770,27 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
int i;
struct pmu_hw_events *cpuc = this_cpu_ptr(cpu_pmu->hw_events);
/* Clear any unused counters to avoid leaking their contents */
for_each_andnot_bit(i, cpu_pmu->cntr_mask, cpuc->used_mask,
ARMPMU_MAX_HWEVENTS) {
if (i == ARMV8_PMU_CYCLE_IDX)
write_pmccntr(0);
else if (i == ARMV8_PMU_INSTR_IDX)
write_pmicntr(0);
else
armv8pmu_write_evcntr(i, 0);
if (is_pmuv3p9(cpu_pmu->pmuver)) {
u64 mask = 0;
for_each_set_bit(i, cpuc->used_mask, ARMPMU_MAX_HWEVENTS) {
if (armv8pmu_event_has_user_read(cpuc->events[i]))
mask |= BIT(i);
}
write_pmuacr(mask);
} else {
/* Clear any unused counters to avoid leaking their contents */
for_each_andnot_bit(i, cpu_pmu->cntr_mask, cpuc->used_mask,
ARMPMU_MAX_HWEVENTS) {
if (i == ARMV8_PMU_CYCLE_IDX)
write_pmccntr(0);
else if (i == ARMV8_PMU_INSTR_IDX)
write_pmicntr(0);
else
armv8pmu_write_evcntr(i, 0);
}
}
update_pmuserenr(ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_CR);
update_pmuserenr(ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_UEN);
}
static void armv8pmu_enable_event(struct perf_event *event)

1
include/linux/perf/arm_pmuv3.h
View File

@ -257,6 +257,7 @@
#define ARMV8_PMU_USERENR_SW (1 << 1) /* PMSWINC can be written at EL0 */
#define ARMV8_PMU_USERENR_CR (1 << 2) /* Cycle counter can be read at EL0 */
#define ARMV8_PMU_USERENR_ER (1 << 3) /* Event counter can be read at EL0 */
#define ARMV8_PMU_USERENR_UEN (1 << 4) /* Fine grained per counter access at EL0 */
/* Mask for writable bits */
#define ARMV8_PMU_USERENR_MASK (ARMV8_PMU_USERENR_EN | ARMV8_PMU_USERENR_SW | \
ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_ER)