x86/cpufeatures, x86/fault: Mark SMAP as disabled when configured out (dae0a105) · Commits · 戴 / test

Add X86_FEATURE_SMAP to the disabled features mask as appropriate and use cpu_feature_enabled() in the fault code. This lets us get rid of a redundant IS_ENABLED(CONFIG_X86_SMAP). Signed-off-by:

Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/fe93332eded3d702f0b0b4cf83928d6830739ba3.1542667307.git.luto@kernel.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/disabled-features.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -16,6 +16,12 @@
		# define DISABLE_MPX (1<<(X86_FEATURE_MPX & 31))
		#endif

		#ifdef CONFIG_X86_SMAP
		# define DISABLE_SMAP 0
		#else
		# define DISABLE_SMAP (1<<(X86_FEATURE_SMAP & 31))
		#endif

		#ifdef CONFIG_X86_INTEL_UMIP
		# define DISABLE_UMIP 0
		#else
		@@ -68,7 +74,7 @@
		#define DISABLED_MASK6 0
		#define DISABLED_MASK7 (DISABLE_PTI)
		#define DISABLED_MASK8 0
		#define DISABLED_MASK9 (DISABLE_MPX)
		#define DISABLED_MASK9 (DISABLE_MPX\|DISABLE_SMAP)
		#define DISABLED_MASK10 0
		#define DISABLED_MASK11 0
		#define DISABLED_MASK12 0

arch/x86/mm/fault.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -1150,10 +1150,7 @@ static int fault_in_kernel_space(unsigned long address)

		static inline bool smap_violation(int error_code, struct pt_regs *regs)
		{
		if (!IS_ENABLED(CONFIG_X86_SMAP))
		return false;

		if (!static_cpu_has(X86_FEATURE_SMAP))
		if (!cpu_feature_enabled(X86_FEATURE_SMAP))
		return false;

		if (error_code & X86_PF_USER)

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