[PATCH v3 19/21] powerpc: Add option to use jump label for mmu_has_feature()
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2016-07-27 14:18:56
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Kevin Hao <redacted>
As we just did for CPU features.
Signed-off-by: Kevin Hao <redacted>
Signed-off-by: Aneesh Kumar K.V <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/include/asm/mmu.h | 36 ++++++++++++++++++++++++++++++++++++
arch/powerpc/kernel/cputable.c | 17 +++++++++++++++++
arch/powerpc/lib/feature-fixups.c | 1 +
3 files changed, 54 insertions(+)
v3: Rename to mmu_feature_keys, and NUM_MMU_FTR_KEYS.
Use the kconfig.
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index e3eff365e55d..3900cb7fe7cf 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h@@ -140,6 +140,41 @@ static inline bool __mmu_has_feature(unsigned long feature) return !!(MMU_FTRS_POSSIBLE & cur_cpu_spec->mmu_features & feature); } +#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS +#include <linux/jump_label.h> + +#define NUM_MMU_FTR_KEYS 32 + +extern struct static_key_true mmu_feature_keys[NUM_MMU_FTR_KEYS]; + +extern void mmu_feature_keys_init(void); + +static __always_inline bool mmu_has_feature(unsigned long feature) +{ + int i; + + if (!(MMU_FTRS_POSSIBLE & feature)) + return false; + + i = __builtin_ctzl(feature); + return static_branch_likely(&mmu_feature_keys[i]); +} + +static inline void mmu_clear_feature(unsigned long feature) +{ + int i; + + i = __builtin_ctzl(feature); + cur_cpu_spec->mmu_features &= ~feature; + static_branch_disable(&mmu_feature_keys[i]); +} +#else + +static inline void mmu_feature_keys_init(void) +{ + +} + static inline bool mmu_has_feature(unsigned long feature) { return __mmu_has_feature(feature);
@@ -149,6 +184,7 @@ static inline void mmu_clear_feature(unsigned long feature) { cur_cpu_spec->mmu_features &= ~feature; } +#endif /* CONFIG_JUMP_LABEL */ extern unsigned int __start___mmu_ftr_fixup, __stop___mmu_ftr_fixup;
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index f268850f8fda..db14efc7d3e0 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c@@ -2243,4 +2243,21 @@ void __init cpu_feature_keys_init(void) static_branch_disable(&cpu_feature_keys[i]); } } + +struct static_key_true mmu_feature_keys[NUM_MMU_FTR_KEYS] = { + [0 ... NUM_MMU_FTR_KEYS - 1] = STATIC_KEY_TRUE_INIT +}; +EXPORT_SYMBOL_GPL(mmu_feature_keys); + +void __init mmu_feature_keys_init(void) +{ + int i; + + for (i = 0; i < NUM_MMU_FTR_KEYS; i++) { + unsigned long f = 1ul << i; + + if (!(cur_cpu_spec->mmu_features & f)) + static_branch_disable(&mmu_feature_keys[i]); + } +} #endif
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index f90423faade0..8db370cec547 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c@@ -196,6 +196,7 @@ void __init apply_feature_fixups(void) */ jump_label_init(); cpu_feature_keys_init(); + mmu_feature_keys_init(); } static int __init check_features(void)
--
2.7.4