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x86, cpu: Expand cpufeature facility to include cpu bugs 

We add another 32-bit vector at the end of the ->x86_capability
bitvector which collects bugs present in CPUs. After all, a CPU bug is a
kind of a capability, albeit a strange one.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1363788448-31325-2-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
hifive-unleashed-5.1
Borislav Petkov 2013-03-20 15:07:23 +01:00 committed by H. Peter Anvin
parent 07961ac7c0
commit 65fc985b37
4 changed files with 19 additions and 2 deletions
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13
arch/x86/include/asm/cpufeature.h
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@ -9,6 +9,7 @@
#endif
#define NCAPINTS 10 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */
/*
* Note: If the comment begins with a quoted string, that string is used
@ -216,6 +217,11 @@
#define X86_FEATURE_ADX (9*32+19) /* The ADCX and ADOX instructions */
#define X86_FEATURE_SMAP (9*32+20) /* Supervisor Mode Access Prevention */
/*
* BUG word(s)
*/
#define X86_BUG(x) (NCAPINTS*32 + (x))
#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
#include <asm/asm.h>
@ -401,6 +407,13 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
#define static_cpu_has(bit) boot_cpu_has(bit)
#endif
#define cpu_has_bug(c, bit) cpu_has(c, (bit))
#define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
#define clear_cpu_bug(c, bit) clear_cpu_cap(c, (bit));
#define static_cpu_has_bug(bit) static_cpu_has((bit))
#define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit))
#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
#endif /* _ASM_X86_CPUFEATURE_H */

2
arch/x86/include/asm/processor.h
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@ -107,7 +107,7 @@ struct cpuinfo_x86 {
__u32 extended_cpuid_level;
/* Maximum supported CPUID level, -1=no CPUID: */
int cpuid_level;
__u32 x86_capability[NCAPINTS];
__u32 x86_capability[NCAPINTS + NBUGINTS];
char x86_vendor_id[16];
char x86_model_id[64];
/* in KB - valid for CPUS which support this call: */

2
arch/x86/kernel/alternative.c
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@ -271,7 +271,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
replacement = (u8 *)&a->repl_offset + a->repl_offset;
BUG_ON(a->replacementlen > a->instrlen);
BUG_ON(a->instrlen > sizeof(insnbuf));
BUG_ON(a->cpuid >= NCAPINTS*32);
BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
if (!boot_cpu_has(a->cpuid))
continue;

4
arch/x86/kernel/cpu/common.c
View File

@ -920,6 +920,10 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
/* AND the already accumulated flags with these */
for (i = 0; i < NCAPINTS; i++)
boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
/* OR, i.e. replicate the bug flags */
for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++)
c->x86_capability[i] |= boot_cpu_data.x86_capability[i];
}
/* Init Machine Check Exception if available. */