Commit 45c39fb0 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86, cleanups: Simplify sync_core() in the case of no CPUID 



Simplify the implementation of sync_core() for the case where we may
not have the CPUID instruction available.

[ v2: stylistic cleanup of the #else clause per suggestion by Borislav
  Petkov. ]

Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1354132230-21854-9-git-send-email-hpa@linux.intel.com
Cc: Borislav Petkov <bp@alien8.de>
parent e3228cf4

arch/x86/include/asm/processor.h

+21 −10
Original line number Diff line number Diff line
@@ -673,17 +673,28 @@ static inline void sync_core(void) 
	int tmp;



#ifdef CONFIG_M486

	if (boot_cpu_data.x86 < 5)

		/* There is no speculative execution.

		 * jmp is a barrier to prefetching. */

		asm volatile("jmp 1f\n1:\n" ::: "memory");

	else

#endif

		/* cpuid is a barrier to speculative execution.

	/*

	 * Do a CPUID if available, otherwise do a jump.  The jump

	 * can conveniently enough be the jump around CPUID.

	 */

	asm volatile("cmpl %2,%1\n\t"

		     "jl 1f\n\t"

		     "cpuid\n"

		     "1:"

		     : "=a" (tmp)

		     : "rm" (boot_cpu_data.cpuid_level), "ri" (0), "0" (1)

		     : "ebx", "ecx", "edx", "memory");

#else

	/*

	 * CPUID is a barrier to speculative execution.

	 * Prefetched instructions are automatically

		 * invalidated when modified. */

		asm volatile("cpuid" : "=a" (tmp) : "0" (1)

	 * invalidated when modified.

	 */

	asm volatile("cpuid"

		     : "=a" (tmp)

		     : "0" (1)

		     : "ebx", "ecx", "edx", "memory");

#endif

}



static inline void __monitor(const void *eax, unsigned long ecx,

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