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Diffstat (limited to 'arch/x86/kernel/alternative.c')
-rw-r--r--arch/x86/kernel/alternative.c46
1 files changed, 18 insertions, 28 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 2763cb37b553..a84ac7b570e6 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -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 */
@@ -241,25 +231,25 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
continue;
if (*ptr > text_end)
continue;
- text_poke(*ptr, ((unsigned char []){0xf0}), 1); /* add lock prefix */
+ /* turn DS segment override prefix into lock prefix */
+ text_poke(*ptr, ((unsigned char []){0xf0}), 1);
};
}
static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
{
u8 **ptr;
- char insn[1];
if (noreplace_smp)
return;
- add_nops(insn, 1);
for (ptr = start; ptr < end; ptr++) {
if (*ptr < text)
continue;
if (*ptr > text_end)
continue;
- text_poke(*ptr, insn, 1);
+ /* turn lock prefix into DS segment override prefix */
+ text_poke(*ptr, ((unsigned char []){0x3E}), 1);
};
}
@@ -454,7 +444,7 @@ void __init alternative_instructions(void)
_text, _etext);
/* Only switch to UP mode if we don't immediately boot others */
- if (num_possible_cpus() == 1 || setup_max_cpus <= 1)
+ if (num_present_cpus() == 1 || setup_max_cpus <= 1)
alternatives_smp_switch(0);
}
#endif