x86: introduce frame_pointer() and stack_pointer()

This patch defines frame_pointer() and stack_pointer() similar to the
already defined instruction_pointer(). Thus the oprofile code can be
written in a more readable fashion.

[ tglx: arch/x86 adaptation ]
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/oprofile/backtrace.c

@@ -76,16 +76,8 @@ dump_user_backtrace(struct frame_head * head)
 void
 x86_backtrace(struct pt_regs * const regs, unsigned int depth)
 {
-	struct frame_head *head;
-	unsigned long stack;
-
-#ifdef CONFIG_X86_64
-	head = (struct frame_head *)regs->rbp;
-	stack = regs->rsp;
-#else
-	head = (struct frame_head *)regs->ebp;
-	stack = regs->esp;
-#endif
+	struct frame_head *head = (struct frame_head *)frame_pointer(regs);
+	unsigned long stack = stack_pointer(regs);
 
 	if (!user_mode_vm(regs)) {
 		if (depth)

include/asm-x86/ptrace_32.h

@@ -55,6 +55,8 @@ static inline int v8086_mode(struct pt_regs *regs)
 }
 
 #define instruction_pointer(regs) ((regs)->eip)
+#define frame_pointer(regs) ((regs)->ebp)
+#define stack_pointer(regs) ((regs)->esp)
 #define regs_return_value(regs) ((regs)->eax)
 
 extern unsigned long profile_pc(struct pt_regs *regs);

include/asm-x86/ptrace_64.h

@@ -40,6 +40,8 @@ struct pt_regs {
 #define user_mode(regs) (!!((regs)->cs & 3))
 #define user_mode_vm(regs) user_mode(regs)
 #define instruction_pointer(regs) ((regs)->rip)
+#define frame_pointer(regs) ((regs)->rbp)
+#define stack_pointer(regs) ((regs)->rsp)
 #define regs_return_value(regs) ((regs)->rax)
 
 extern unsigned long profile_pc(struct pt_regs *regs);