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arm64: cpufeature: Detect CPU RAS Extentions

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ARM's v8.2 Extentions add support for Reliability, Availability and
Serviceability (RAS). On CPUs with these extensions system software
can use additional barriers to isolate errors and determine if faults
are pending. Add cpufeature detection.

Platform level RAS support may require additional firmware support.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
[Rebased added config option, reworded commit message]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Xie XiuQi 2018-01-15 19:38:56 +00:00 committed by Catalin Marinas
parent 7a00d68ebe
commit 64c02720ea
4 changed files with 33 additions and 1 deletions
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16
arch/arm64/Kconfig
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@ -1062,6 +1062,22 @@ config ARM64_PMEM
operations if DC CVAP is not supported (following the behaviour of
DC CVAP itself if the system does not define a point of persistence).
config ARM64_RAS_EXTN
bool "Enable support for RAS CPU Extensions"
default y
help
CPUs that support the Reliability, Availability and Serviceability
(RAS) Extensions, part of ARMv8.2 are able to track faults and
errors, classify them and report them to software.
On CPUs with these extensions system software can use additional
barriers to determine if faults are pending and read the
classification from a new set of registers.
Selecting this feature will allow the kernel to use these barriers
and access the new registers if the system supports the extension.
Platform RAS features may additionally depend on firmware support.
endmenu
config ARM64_SVE

3
arch/arm64/include/asm/cpucaps.h
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@ -44,7 +44,8 @@
#define ARM64_UNMAP_KERNEL_AT_EL0 23
#define ARM64_HARDEN_BRANCH_PREDICTOR 24
#define ARM64_HARDEN_BP_POST_GUEST_EXIT 25
#define ARM64_HAS_RAS_EXTN 26
#define ARM64_NCAPS 26
#define ARM64_NCAPS 27
#endif /* __ASM_CPUCAPS_H */

2
arch/arm64/include/asm/sysreg.h
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@ -498,6 +498,7 @@
#define ID_AA64PFR0_CSV3_SHIFT 60
#define ID_AA64PFR0_CSV2_SHIFT 56
#define ID_AA64PFR0_SVE_SHIFT 32
#define ID_AA64PFR0_RAS_SHIFT 28
#define ID_AA64PFR0_GIC_SHIFT 24
#define ID_AA64PFR0_ASIMD_SHIFT 20
#define ID_AA64PFR0_FP_SHIFT 16
@ -507,6 +508,7 @@
#define ID_AA64PFR0_EL0_SHIFT 0
#define ID_AA64PFR0_SVE 0x1
#define ID_AA64PFR0_RAS_V1 0x1
#define ID_AA64PFR0_FP_NI 0xf
#define ID_AA64PFR0_FP_SUPPORTED 0x0
#define ID_AA64PFR0_ASIMD_NI 0xf

13
arch/arm64/kernel/cpufeature.c
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@ -149,6 +149,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0),
S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI),
S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_FP_SHIFT, 4, ID_AA64PFR0_FP_NI),
@ -1028,6 +1029,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.enable = sve_kernel_enable,
},
#endif /* CONFIG_ARM64_SVE */
#ifdef CONFIG_ARM64_RAS_EXTN
{
.desc = "RAS Extension Support",
.capability = ARM64_HAS_RAS_EXTN,
.def_scope = SCOPE_SYSTEM,
.matches = has_cpuid_feature,
.sys_reg = SYS_ID_AA64PFR0_EL1,
.sign = FTR_UNSIGNED,
.field_pos = ID_AA64PFR0_RAS_SHIFT,
.min_field_value = ID_AA64PFR0_RAS_V1,
},
#endif /* CONFIG_ARM64_RAS_EXTN */
{},
};