arm64: cpufeature: Don't enforce system-wide SPE capability

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>

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 98ae03f..e156e77 100644 (file)
--- 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 d9714ad..e8f6dfb 100644 (file)
--- 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),