1 files changed, 16 insertions, 8 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index fc944b5e8f4a..af425a8049fb 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -471,8 +471,7 @@ void __init setup_arch(char **cmdline_p)
         if (LOADER_TYPE && INITRD_START) {
                 if (INITRD_START + INITRD_SIZE <= (end_pfn << PAGE_SHIFT)) {
                         reserve_bootmem_generic(INITRD_START, INITRD_SIZE);
-                        initrd_start =
-                                INITRD_START ? INITRD_START + PAGE_OFFSET : 0;
+                        initrd_start = INITRD_START + PAGE_OFFSET;
                         initrd_end = initrd_start+INITRD_SIZE;
                 }
                 else {
@@ -732,11 +731,8 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
         /* Fix cpuid4 emulation for more */
         num_cache_leaves = 3;
 
-        /* When there is only one core no need to synchronize RDTSC */
-        if (num_possible_cpus() == 1)
-                set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
-        else
-                clear_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
+        /* RDTSC can be speculated around */
+        clear_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
 }
 
 static void __cpuinit detect_ht(struct cpuinfo_x86 *c)
@@ -835,6 +831,15 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
                         set_bit(X86_FEATURE_ARCH_PERFMON, &c->x86_capability);
         }
 
+        if (cpu_has_ds) {
+                unsigned int l1, l2;
+                rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
+                if (!(l1 & (1<<11)))
+                        set_bit(X86_FEATURE_BTS, c->x86_capability);
+                if (!(l1 & (1<<12)))
+                        set_bit(X86_FEATURE_PEBS, c->x86_capability);
+        }
+
         n = c->extended_cpuid_level;
         if (n >= 0x80000008) {
                 unsigned eax = cpuid_eax(0x80000008);
@@ -854,7 +859,10 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
                 set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
         if (c->x86 == 6)
                 set_bit(X86_FEATURE_REP_GOOD, &c->x86_capability);
-        set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
+        if (c->x86 == 15)
+                set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
+        else
+                clear_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
         c->x86_max_cores = intel_num_cpu_cores(c);
 
         srat_detect_node();