diff options
Diffstat (limited to 'arch/arm64/include/asm/cpufeature.h')
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index b4989df48670..4ce82ed3e7c3 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -29,7 +29,20 @@ #include <linux/jump_label.h> #include <linux/kernel.h> -/* CPU feature register tracking */ +/* + * CPU feature register tracking + * + * The safe value of a CPUID feature field is dependent on the implications + * of the values assigned to it by the architecture. Based on the relationship + * between the values, the features are classified into 3 types - LOWER_SAFE, + * HIGHER_SAFE and EXACT. + * + * The lowest value of all the CPUs is chosen for LOWER_SAFE and highest + * for HIGHER_SAFE. It is expected that all CPUs have the same value for + * a field when EXACT is specified, failing which, the safe value specified + * in the table is chosen. + */ + enum ftr_type { FTR_EXACT, /* Use a predefined safe value */ FTR_LOWER_SAFE, /* Smaller value is safe */ @@ -42,8 +55,12 @@ enum ftr_type { #define FTR_SIGNED true /* Value should be treated as signed */ #define FTR_UNSIGNED false /* Value should be treated as unsigned */ +#define FTR_VISIBLE true /* Feature visible to the user space */ +#define FTR_HIDDEN false /* Feature is hidden from the user */ + struct arm64_ftr_bits { bool sign; /* Value is signed ? */ + bool visible; bool strict; /* CPU Sanity check: strict matching required ? */ enum ftr_type type; u8 shift; @@ -59,7 +76,9 @@ struct arm64_ftr_bits { struct arm64_ftr_reg { const char *name; u64 strict_mask; + u64 user_mask; u64 sys_val; + u64 user_val; const struct arm64_ftr_bits *ftr_bits; }; @@ -159,6 +178,11 @@ static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp) return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift); } +static inline u64 arm64_ftr_reg_user_value(const struct arm64_ftr_reg *reg) +{ + return (reg->user_val | (reg->sys_val & reg->user_mask)); +} + static inline int __attribute_const__ cpuid_feature_extract_field(u64 features, int field, bool sign) { |