diff options
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index b4989df48670..10d56242e649 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 */ |