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x86: Remove FAST_FEATURE_TESTS

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Since we want to rely on static branches to avoid speculation, remove
any possible fallback code for static_cpu_has.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: torvalds@linux-foundation.org
Link: https://lkml.kernel.org/r/20180319154717.705383007@infradead.org
This commit is contained in:
Peter Zijlstra 2018-03-19 16:41:26 +01:00 committed by Thomas Gleixner
parent e501ce957a
commit d0266046ad
2 changed files with 0 additions and 19 deletions
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11
arch/x86/Kconfig
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@ -393,17 +393,6 @@ config X86_FEATURE_NAMES
If in doubt, say Y.
config X86_FAST_FEATURE_TESTS
bool "Fast CPU feature tests" if EMBEDDED
default y
---help---
Some fast-paths in the kernel depend on the capabilities of the CPU.
Say Y here for the kernel to patch in the appropriate code at runtime
based on the capabilities of the CPU. The infrastructure for patching
code at runtime takes up some additional space; space-constrained
embedded systems may wish to say N here to produce smaller, slightly
slower code.
config X86_X2APIC
bool "Support x2apic"
depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)

8
arch/x86/include/asm/cpufeature.h
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@ -140,7 +140,6 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS)
/*
* Static testing of CPU features. Used the same as boot_cpu_has().
* These will statically patch the target code for additional
@ -196,13 +195,6 @@ t_no:
boot_cpu_has(bit) : \
_static_cpu_has(bit) \
)
#else
/*
* Fall back to dynamic for gcc versions which don't support asm goto. Should be
* a minority now anyway.
*/
#define static_cpu_has(bit) boot_cpu_has(bit)
#endif
#define cpu_has_bug(c, bit) cpu_has(c, (bit))
#define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))