1 files changed, 4 insertions, 33 deletions

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c84bbd4298a0..cbc251981209 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -155,12 +155,8 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
 	    ((unsigned long)ptr & 7))
 		return -EFAULT;
 
-	pagefault_disable();
-	if (!__get_user_inatomic(*ret, ptr)) {
-		pagefault_enable();
+	if (!probe_user_read(ret, ptr, sizeof(*ret)))
 		return 0;
-	}
-	pagefault_enable();
 
 	return read_user_stack_slow(ptr, ret, 8);
 }
@@ -171,12 +167,8 @@ static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
 	    ((unsigned long)ptr & 3))
 		return -EFAULT;
 
-	pagefault_disable();
-	if (!__get_user_inatomic(*ret, ptr)) {
-		pagefault_enable();
+	if (!probe_user_read(ret, ptr, sizeof(*ret)))
 		return 0;
-	}
-	pagefault_enable();
 
 	return read_user_stack_slow(ptr, ret, 4);
 }
@@ -284,16 +276,6 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
 	}
 }
 
-static inline int current_is_64bit(void)
-{
-	/*
-	 * We can't use test_thread_flag() here because we may be on an
-	 * interrupt stack, and the thread flags don't get copied over
-	 * from the thread_info on the main stack to the interrupt stack.
-	 */
-	return !test_ti_thread_flag(task_thread_info(current), TIF_32BIT);
-}
-
 #else  /* CONFIG_PPC64 */
 /*
  * On 32-bit we just access the address and let hash_page create a
@@ -303,17 +285,11 @@ static inline int current_is_64bit(void)
  */
 static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
 {
-	int rc;
-
 	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
 	    ((unsigned long)ptr & 3))
 		return -EFAULT;
 
-	pagefault_disable();
-	rc = __get_user_inatomic(*ret, ptr);
-	pagefault_enable();
-
-	return rc;
+	return probe_user_read(ret, ptr, sizeof(*ret));
 }
 
 static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
@@ -321,11 +297,6 @@ static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry
 {
 }
 
-static inline int current_is_64bit(void)
-{
-	return 0;
-}
-
 static inline int valid_user_sp(unsigned long sp, int is_64)
 {
 	if (!sp || (sp & 7) || sp > TASK_SIZE - 32)
@@ -486,7 +457,7 @@ static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
 void
 perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
 {
-	if (current_is_64bit())
+	if (!is_32bit_task())
 		perf_callchain_user_64(entry, regs);
 	else
 		perf_callchain_user_32(entry, regs);