[PATCH 05/16] arm64: Add flags to check the safety of a capability for late CPU
From: suzuki.poulose@arm.com (Suzuki K Poulose)
Date: 2018-01-23 12:31:06
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Add two different flags to indicate if the conflict of a capability
on a late CPU with the current system state
1) Can a CPU have a capability when the system doesn't have it ?
Most arm64 features could have this set. While erratum work arounds
cannot have this, as we may miss work arounds.
2) Can a CPU miss a capability when the system has it ?
This could be set for arm64 erratum work arounds as we don't
care if a CPU doesn't need the work around. However it should
be clear for features.
These flags could be added to certain entries based on their nature.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arch/arm64/include/asm/cpufeature.h | 35 +++++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 4fd5de8ef33e..27d037bb0451 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -94,10 +94,25 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; #define SCOPE_SYSTEM ARM64_CPUCAP_SCOPE_SYSTEM #define SCOPE_LOCAL_CPU ARM64_CPUCAP_SCOPE_LOCAL_CPU -/* CPU errata detected at boot time based on feature of one or more CPUs */ -#define ARM64_CPUCAP_STRICT_CPU_LOCAL_ERRATUM (ARM64_CPUCAP_SCOPE_LOCAL_CPU) -/* CPU feature detected at boot time based on system-wide value of a feature */ -#define ARM64_CPUCAP_BOOT_SYSTEM_FEATURE (ARM64_CPUCAP_SCOPE_SYSTEM) +/* Is it safe for a late CPU to have this capability when system doesn't already have */ +#define ARM64_CPUCAP_LATE_CPU_SAFE_TO_HAVE BIT(2) +/* Is it safe for a late CPU to miss this capability when system has it */ +#define ARM64_CPUCAP_LATE_CPU_SAFE_TO_MISS BIT(3) + +/* + * CPU errata detected at boot time based on feature of one or more CPUs. + * It is not safe for a late CPU to have this feature when the system doesn't + * have it. But it is safe to miss the feature if the system has it. + */ +#define ARM64_CPUCAP_STRICT_CPU_LOCAL_ERRATUM \ + (ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_LATE_CPU_SAFE_TO_MISS) +/* + * CPU feature detected at boot time based on system-wide value of a feature. + * It is safe for a late CPU to have this feature even though the system doesn't + * have it already. But the CPU must have this feature if the system does. + */ +#define ARM64_CPUCAP_BOOT_SYSTEM_FEATURE \ + (ARM64_CPUCAP_SCOPE_SYSTEM | ARM64_CPUCAP_LATE_CPU_SAFE_TO_HAVE) struct arm64_cpu_capabilities { const char *desc;
@@ -128,6 +143,18 @@ static inline int cpucap_default_scope(const struct arm64_cpu_capabilities *cap) return cap->type & ARM64_CPUCAP_SCOPE_MASK; } +static inline bool +cpucap_late_cpu_missing_cap_safe(const struct arm64_cpu_capabilities *cap) +{ + return !!(cap->type & ARM64_CPUCAP_LATE_CPU_SAFE_TO_MISS); +} + +static inline bool +cpucap_late_cpu_have_cap_safe(const struct arm64_cpu_capabilities *cap) +{ + return !!(cap->type & ARM64_CPUCAP_LATE_CPU_SAFE_TO_HAVE); +} + extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS]; extern struct static_key_false arm64_const_caps_ready;
--
2.13.6