1 files changed, 11 insertions, 17 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e638689279d3..3a0338b4b179 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -31,6 +31,7 @@
 #include <asm/nmi.h>
 #include <asm/compat.h>
 #include <asm/smp.h>
+#include <asm/alternative.h>
 
 #if 0
 #undef wrmsrl
@@ -363,12 +364,18 @@ again:
         return new_raw_count;
 }
 
-/* using X86_FEATURE_PERFCTR_CORE to later implement ALTERNATIVE() here */
 static inline int x86_pmu_addr_offset(int index)
 {
-        if (boot_cpu_has(X86_FEATURE_PERFCTR_CORE))
-                return index << 1;
-        return index;
+        int offset;
+
+        /* offset = X86_FEATURE_PERFCTR_CORE ? index << 1 : index */
+        alternative_io(ASM_NOP2,
+                       "shll $1, %%eax",
+                       X86_FEATURE_PERFCTR_CORE,
+                       "=a" (offset),
+                       "a"  (index));
+
+        return offset;
 }
 
 static inline unsigned int x86_pmu_config_addr(int index)
@@ -1766,17 +1773,6 @@ static struct pmu pmu = {
  * callchain support
  */
 
-static void
-backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
-{
-        /* Ignore warnings */
-}
-
-static void backtrace_warning(void *data, char *msg)
-{
-        /* Ignore warnings */
-}
-
 static int backtrace_stack(void *data, char *name)
 {
         return 0;
@@ -1790,8 +1786,6 @@ static void backtrace_address(void *data, unsigned long addr, int reliable)
 }
 
 static const struct stacktrace_ops backtrace_ops = {
-        .warning                = backtrace_warning,
-        .warning_symbol         = backtrace_warning_symbol,
         .stack                  = backtrace_stack,
         .address                = backtrace_address,
         .walk_stack             = print_context_stack_bp,