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>

4 files changed, 19 insertions, 2 deletions

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 93fe929d1cee..16190abd8905 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -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 */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 3270116b1488..23c8081d3870 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -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: */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index ef5ccca79a6c..c15cf9a25e27 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -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;
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index d814772c5bed..22018f70a671 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -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. */