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Commit f31d731e authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86: use X86_FEATURE_NOPL in alternatives 



Use X86_FEATURE_NOPL to determine if it is safe to use P6 NOPs in
alternatives.  Also, replace table and loop with simple if statement.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent b6734c35

arch/x86/kernel/alternative.c

+13 −23
Original line number Diff line number Diff line
@@ -145,35 +145,25 @@ static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = { 
extern char __vsyscall_0;

const unsigned char *const *find_nop_table(void)

{

	return boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||

	       boot_cpu_data.x86 < 6 ? k8_nops : p6_nops;

	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&

	    boot_cpu_has(X86_FEATURE_NOPL))

		return p6_nops;

	else

		return k8_nops;

}



#else /* CONFIG_X86_64 */



static const struct nop {

	int cpuid;

	const unsigned char *const *noptable;

} noptypes[] = {

	{ X86_FEATURE_K8, k8_nops },

	{ X86_FEATURE_K7, k7_nops },

	{ X86_FEATURE_P4, p6_nops },

	{ X86_FEATURE_P3, p6_nops },

	{ -1, NULL }

};



const unsigned char *const *find_nop_table(void)

{

	const unsigned char *const *noptable = intel_nops;

	int i;



	for (i = 0; noptypes[i].cpuid >= 0; i++) {

		if (boot_cpu_has(noptypes[i].cpuid)) {

			noptable = noptypes[i].noptable;

			break;

		}

	}

	return noptable;

	if (boot_cpu_has(X86_FEATURE_K8))

		return k8_nops;

	else if (boot_cpu_has(X86_FEATURE_K7))

		return k7_nops;

	else if (boot_cpu_has(X86_FEATURE_NOPL))

		return p6_nops;

	else

		return intel_nops;

}



#endif /* CONFIG_X86_64 */