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Subject[PATCH 02/10] arm64: cpufeature: Don't enforce system-wide SPE capability
Date
The statistical profiling extension (SPE) is an optional feature of
ARMv8.1 and is unlikely to be supported by all of the CPUs in a
heterogeneous system.

This patch updates the cpufeature checks so that such systems are not
tainted as unsupported.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/sysreg.h | 1 +
arch/arm64/kernel/cpufeature.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 98ae03f8eedd..e156e7793a65 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -190,6 +190,7 @@
#define ID_AA64MMFR2_CNP_SHIFT 0

/* id_aa64dfr0 */
+#define ID_AA64DFR0_PMSVER_SHIFT 32
#define ID_AA64DFR0_CTX_CMPS_SHIFT 28
#define ID_AA64DFR0_WRPS_SHIFT 20
#define ID_AA64DFR0_BRPS_SHIFT 12
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 47d0226620e8..c18eb78d3a00 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -180,7 +180,8 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
};

static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
- ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 32, 32, 0),
+ ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, 36, 28, 0),
+ ARM64_FTR_BITS(FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_PMSVER_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_BRPS_SHIFT, 4, 0),
--
2.1.4
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