Commit d938ba17 authored by Donglin Peng's avatar Donglin Peng Committed by Steven Rostedt (Google)
Browse files

x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL 

The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the x86 platform.

We introduce a new structure called fgraph_ret_regs for the x86
platform to hold return registers and the frame pointer. We then
fill its content in the return_to_handler and pass its address
to the function ftrace_return_to_handler to record the return
value.

Link: https://lkml.kernel.org/r/53a506f0f18ff4b7aeb0feb762f1c9a5e9b83ee9.1680954589.git.pengdonglin@sangfor.com.cn



Signed-off-by: default avatarDonglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 36469703

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -216,6 +216,7 @@ config X86 
	select HAVE_FAST_GUP

	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)

	select HAVE_FUNCTION_TRACER

	select HAVE_GCC_PLUGINS

arch/x86/include/asm/ftrace.h

+20 −0
Original line number Diff line number Diff line
@@ -147,4 +147,24 @@ static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) 
#endif /* !COMPILE_OFFSETS */

#endif /* !__ASSEMBLY__ */



#ifndef __ASSEMBLY__

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

struct fgraph_ret_regs {

	unsigned long ax;

	unsigned long dx;

	unsigned long bp;

};



static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->ax;

}



static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->bp;

}

#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */

#endif



#endif /* _ASM_X86_FTRACE_H */

arch/x86/kernel/ftrace_32.S

+5 −3
Original line number Diff line number Diff line
@@ -187,12 +187,14 @@ SYM_CODE_END(ftrace_graph_caller) 


.globl return_to_handler

return_to_handler:

	pushl	%eax

	pushl	$0

	pushl	%edx

	movl	$0, %eax

	pushl	%eax

	movl	%esp, %eax

	call	ftrace_return_to_handler

	movl	%eax, %ecx

	popl	%edx

	popl	%eax

	popl	%edx

	addl	$4, %esp		# skip ebp

	JMP_NOSPEC ecx

#endif

arch/x86/kernel/ftrace_64.S

+4 −3
Original line number Diff line number Diff line
@@ -348,12 +348,13 @@ STACK_FRAME_NON_STANDARD_FP(__fentry__) 
SYM_CODE_START(return_to_handler)

	UNWIND_HINT_UNDEFINED

	ANNOTATE_NOENDBR

	subq  $16, %rsp

	subq  $24, %rsp



	/* Save the return values */

	movq %rax, (%rsp)

	movq %rdx, 8(%rsp)

	movq %rbp, %rdi

	movq %rbp, 16(%rsp)

	movq %rsp, %rdi



	call ftrace_return_to_handler
@@ -361,7 +362,7 @@ SYM_CODE_START(return_to_handler) 
	movq 8(%rsp), %rdx

	movq (%rsp), %rax



	addq $16, %rsp

	addq $24, %rsp

	/*

	 * Jump back to the old return address. This cannot be JMP_NOSPEC rdi

	 * since IBT would demand that contain ENDBR, which simply isn't so for