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powerpc: Add option to use jump label for mmu_has_feature()

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As we just did for CPU features.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Kevin Hao 2016-07-23 14:42:42 +05:30 committed by Michael Ellerman
parent 4db7327194
commit c12e6f24d4
4 changed files with 57 additions and 0 deletions
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1
arch/powerpc/include/asm/cpu_has_feature.h
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@ -3,6 +3,7 @@
#ifndef __ASSEMBLY__
#include <linux/bug.h>
#include <asm/cputable.h>
static inline bool early_cpu_has_feature(unsigned long feature)

38
arch/powerpc/include/asm/mmu.h
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@ -141,6 +141,43 @@ static inline bool early_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;
BUILD_BUG_ON(!__builtin_constant_p(feature));
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 early_mmu_has_feature(feature);
@ -150,6 +187,7 @@ 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;

17
arch/powerpc/kernel/cputable.c
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@ -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

1
arch/powerpc/lib/feature-fixups.c
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@ -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)