Re: [RFC] x86: entry_64 - introduce FTRACE_ frame macro

[Cyrill Gorcunov <gorcunov@gmail.com>]

[Steven Rostedt - Fri, Dec 12, 2008 at 04:22:49PM -0500]
...
| > Index: linux-2.6.git/arch/x86/include/asm/ftrace.h
| > ===================================================================
| > --- linux-2.6.git.orig/arch/x86/include/asm/ftrace.h
| > +++ linux-2.6.git/arch/x86/include/asm/ftrace.h
| > @@ -1,6 +1,33 @@
| >  #ifndef _ASM_X86_FTRACE_H
| >  #define _ASM_X86_FTRACE_H
| >  
| > +#ifdef __ASSEMBLY__
| 
| Why add assembly condition? We only want this if CONFIG_FUNCTION_TRACER 
| is enabled, right?  We could combine it with the current #ifndef inside 
| the CONFIG_FUNCTION_TRACER. But I would make do:
| 
| #ifdef __ASSEMBLY__
| <your stuff>
| #else
| < C stuff >
| #endif
| 
| -- Steve

Steve, here is how it could look like:
(I liked first proposal more :)

---
 arch/x86/include/asm/ftrace.h |   36 ++++++++++++++++++++++----
 arch/x86/kernel/entry_64.S    |   57 +++++-------------------------------------
 2 files changed, 37 insertions(+), 56 deletions(-)

Index: linux-2.6.git/arch/x86/include/asm/ftrace.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/ftrace.h
+++ linux-2.6.git/arch/x86/include/asm/ftrace.h
@@ -1,11 +1,37 @@
 #ifndef _ASM_X86_FTRACE_H
 #define _ASM_X86_FTRACE_H
 
+#ifdef __ASSEMBLY__
+
+	.macro FTRACE_SAVE_FRAME
+	/* taken from glibc */
+	subq $0x38, %rsp
+	movq %rax, (%rsp)
+	movq %rcx, 8(%rsp)
+	movq %rdx, 16(%rsp)
+	movq %rsi, 24(%rsp)
+	movq %rdi, 32(%rsp)
+	movq %r8, 40(%rsp)
+	movq %r9, 48(%rsp)
+	.endm
+
+	.macro FTRACE_RESTORE_FRAME
+	movq 48(%rsp), %r9
+	movq 40(%rsp), %r8
+	movq 32(%rsp), %rdi
+	movq 24(%rsp), %rsi
+	movq 16(%rsp), %rdx
+	movq 8(%rsp), %rcx
+	movq (%rsp), %rax
+	addq $0x38, %rsp
+	.endm
+
+#else /* !__ASSEMBLY__ */
+
 #ifdef CONFIG_FUNCTION_TRACER
 #define MCOUNT_ADDR		((long)(mcount))
 #define MCOUNT_INSN_SIZE	5 /* sizeof mcount call */
 
-#ifndef __ASSEMBLY__
 extern void mcount(void);
 
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
@@ -25,13 +51,10 @@ struct dyn_arch_ftrace {
 };
 
 #endif /*  CONFIG_DYNAMIC_FTRACE */
-#endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_TRACER */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
-#ifndef __ASSEMBLY__
-
 /*
  * Stack of return addresses for functions
  * of a thread.
@@ -46,11 +69,12 @@ struct ftrace_ret_stack {
 /*
  * Primary handler of a function return.
  * It relays on ftrace_return_to_handler.
- * Defined in entry32.S
+ * Defined in entry_32/64.S
  */
 extern void return_to_handler(void);
 
-#endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
+#endif /* !__ASSEMBLY__ */
+
 #endif /* _ASM_X86_FTRACE_H */
Index: linux-2.6.git/arch/x86/kernel/entry_64.S
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/entry_64.S
+++ linux-2.6.git/arch/x86/kernel/entry_64.S
@@ -70,15 +70,7 @@ ENTRY(ftrace_caller)
 	cmpl $0, function_trace_stop
 	jne  ftrace_stub
 
-	/* taken from glibc */
-	subq $0x38, %rsp
-	movq %rax, (%rsp)
-	movq %rcx, 8(%rsp)
-	movq %rdx, 16(%rsp)
-	movq %rsi, 24(%rsp)
-	movq %rdi, 32(%rsp)
-	movq %r8, 40(%rsp)
-	movq %r9, 48(%rsp)
+	FTRACE_SAVE_FRAME
 
 	movq 0x38(%rsp), %rdi
 	movq 8(%rbp), %rsi
@@ -88,14 +80,7 @@ ENTRY(ftrace_caller)
 ftrace_call:
 	call ftrace_stub
 
-	movq 48(%rsp), %r9
-	movq 40(%rsp), %r8
-	movq 32(%rsp), %rdi
-	movq 24(%rsp), %rsi
-	movq 16(%rsp), %rdx
-	movq 8(%rsp), %rcx
-	movq (%rsp), %rax
-	addq $0x38, %rsp
+	FTRACE_RESTORE_FRAME
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 .globl ftrace_graph_call
@@ -129,15 +114,7 @@ ftrace_stub:
 	retq
 
 trace:
-	/* taken from glibc */
-	subq $0x38, %rsp
-	movq %rax, (%rsp)
-	movq %rcx, 8(%rsp)
-	movq %rdx, 16(%rsp)
-	movq %rsi, 24(%rsp)
-	movq %rdi, 32(%rsp)
-	movq %r8, 40(%rsp)
-	movq %r9, 48(%rsp)
+	FTRACE_SAVE_FRAME
 
 	movq 0x38(%rsp), %rdi
 	movq 8(%rbp), %rsi
@@ -145,14 +122,7 @@ trace:
 
 	call   *ftrace_trace_function
 
-	movq 48(%rsp), %r9
-	movq 40(%rsp), %r8
-	movq 32(%rsp), %rdi
-	movq 24(%rsp), %rsi
-	movq 16(%rsp), %rdx
-	movq 8(%rsp), %rcx
-	movq (%rsp), %rax
-	addq $0x38, %rsp
+	FTRACE_RESTORE_FRAME
 
 	jmp ftrace_stub
 END(mcount)
@@ -164,14 +134,7 @@ ENTRY(ftrace_graph_caller)
 	cmpl $0, function_trace_stop
 	jne ftrace_stub
 
-	subq $0x38, %rsp
-	movq %rax, (%rsp)
-	movq %rcx, 8(%rsp)
-	movq %rdx, 16(%rsp)
-	movq %rsi, 24(%rsp)
-	movq %rdi, 32(%rsp)
-	movq %r8, 40(%rsp)
-	movq %r9, 48(%rsp)
+	FTRACE_SAVE_FRAME
 
 	leaq 8(%rbp), %rdi
 	movq 0x38(%rsp), %rsi
@@ -179,14 +142,8 @@ ENTRY(ftrace_graph_caller)
 
 	call	prepare_ftrace_return
 
-	movq 48(%rsp), %r9
-	movq 40(%rsp), %r8
-	movq 32(%rsp), %rdi
-	movq 24(%rsp), %rsi
-	movq 16(%rsp), %rdx
-	movq 8(%rsp), %rcx
-	movq (%rsp), %rax
-	addq $0x38, %rsp
+	FTRACE_RESTORE_FRAME
+
 	retq
 END(ftrace_graph_caller)
 
		- Cyrill -