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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: H. Peter Anvin <hpa@zytor.com>
hifive-unleashed-5.1
H. Peter Anvin 2008-08-18 17:50:33 -07:00
parent b6734c35af
commit f31d731e44
1 changed files with 13 additions and 23 deletions
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36
arch/x86/kernel/alternative.c
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@ -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 */