4.4-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov bp@suse.de
commit 6e1315fe82308cd29e7550eab967262e8bbc71a3 upstream
This brings .text savings of about ~1.6K when building a tinyconfig. It is off by default so nothing changes for the default.
Kconfig help text from Josh.
Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Josh Triplett josh@joshtriplett.org Link: http://lkml.kernel.org/r/1449481182-27541-5-git-send-email-bp@alien8.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Srivatsa S. Bhat srivatsa@csail.mit.edu Reviewed-by: Matt Helsley (VMware) matt.helsley@gmail.com Reviewed-by: Alexey Makhalov amakhalov@vmware.com Reviewed-by: Bo Gan ganb@vmware.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org ---
arch/x86/Kconfig | 11 +++++++++++ arch/x86/include/asm/cpufeature.h | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-)
--- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -346,6 +346,17 @@ 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) --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -422,7 +422,7 @@ extern const char * const x86_bug_flags[ * fast paths and boot_cpu_has() otherwise! */
-#if __GNUC__ >= 4 +#if __GNUC__ >= 4 && defined(CONFIG_X86_FAST_FEATURE_TESTS) extern void warn_pre_alternatives(void); extern bool __static_cpu_has_safe(u16 bit);