Merge branch 'x86/mem' into perf/core

Merge reason: memcpy_64.S changes an assumption perf bench has, so merge this
              here so we can fix it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 25 insertions, 6 deletions

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 651454b0c811..1eeeafcb4410 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -210,6 +210,15 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
         u8 insnbuf[MAX_PATCH_LEN];
 
         DPRINTK("%s: alt table %p -> %p\n", __func__, start, end);
+        /*
+         * The scan order should be from start to end. A later scanned
+         * alternative code can overwrite a previous scanned alternative code.
+         * Some kernel functions (e.g. memcpy, memset, etc) use this order to
+         * patch code.
+         *
+         * So be careful if you want to change the scan order to any other
+         * order.
+         */
         for (a = start; a < end; a++) {
                 u8 *instr = a->instr;
                 BUG_ON(a->replacementlen > a->instrlen);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e2ced0074a45..173f3a3fa1a6 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -565,8 +565,7 @@ void __cpuinit get_cpu_cap(struct cpuinfo_x86 *c)
 
                 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
 
-                if (eax > 0)
-                        c->x86_capability[9] = ebx;
+                c->x86_capability[9] = ebx;
         }
 
         /* AMD-defined flags: level 0x80000001 */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index df86bc8c859d..fc73a34ba8c9 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -29,10 +29,10 @@
 
 static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
 {
+        u64 misc_enable;
+
         /* Unmask CPUID levels if masked: */
         if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
-                u64 misc_enable;
-
                 rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
 
                 if (misc_enable & MSR_IA32_MISC_ENABLE_LIMIT_CPUID) {
@@ -118,8 +118,6 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
          * (model 2) with the same problem.
          */
         if (c->x86 == 15) {
-                u64 misc_enable;
-
                 rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
 
                 if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) {
@@ -130,6 +128,19 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
                 }
         }
 #endif
+
+        /*
+         * If fast string is not enabled in IA32_MISC_ENABLE for any reason,
+         * clear the fast string and enhanced fast string CPU capabilities.
+         */
+        if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
+                rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+                if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) {
+                        printk(KERN_INFO "Disabled fast string operations\n");
+                        setup_clear_cpu_cap(X86_FEATURE_REP_GOOD);
+                        setup_clear_cpu_cap(X86_FEATURE_ERMS);
+                }
+        }
 }
 
 #ifdef CONFIG_X86_32