Commit 36469703 authored by Donglin Peng's avatar Donglin Peng Committed by Steven Rostedt (Google)
Browse files

arm64: 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 ARM64 platform.

We introduce a new structure called fgraph_ret_regs for the ARM64
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/c78366416ce93f704ae7000c4ee60eb4258c38f7.1680954589.git.pengdonglin@sangfor.com.cn



Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarDonglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 21c094d3

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ config ARM64 
	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_TRACER

	select HAVE_FUNCTION_ERROR_INJECTION

	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_GCC_PLUGINS

	select HAVE_HW_BREAKPOINT if PERF_EVENTS

arch/arm64/include/asm/ftrace.h

+22 −0
Original line number Diff line number Diff line
@@ -192,4 +192,26 @@ static inline bool arch_syscall_match_sym_name(const char *sym, 
}

#endif /* ifndef __ASSEMBLY__ */



#ifndef __ASSEMBLY__

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

struct fgraph_ret_regs {

	/* x0 - x7 */

	unsigned long regs[8];



	unsigned long fp;

	unsigned long __unused;

};



static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->regs[0];

}



static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->fp;

}

#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER  */

#endif



#endif /* __ASM_FTRACE_H */

arch/arm64/kernel/asm-offsets.c

+13 −0
Original line number Diff line number Diff line
@@ -200,6 +200,19 @@ int main(void) 
#endif

#ifdef CONFIG_FUNCTION_TRACER

  DEFINE(FTRACE_OPS_FUNC,		offsetof(struct ftrace_ops, func));

#endif

  BLANK();

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

  DEFINE(FGRET_REGS_X0,			offsetof(struct fgraph_ret_regs, regs[0]));

  DEFINE(FGRET_REGS_X1,			offsetof(struct fgraph_ret_regs, regs[1]));

  DEFINE(FGRET_REGS_X2,			offsetof(struct fgraph_ret_regs, regs[2]));

  DEFINE(FGRET_REGS_X3,			offsetof(struct fgraph_ret_regs, regs[3]));

  DEFINE(FGRET_REGS_X4,			offsetof(struct fgraph_ret_regs, regs[4]));

  DEFINE(FGRET_REGS_X5,			offsetof(struct fgraph_ret_regs, regs[5]));

  DEFINE(FGRET_REGS_X6,			offsetof(struct fgraph_ret_regs, regs[6]));

  DEFINE(FGRET_REGS_X7,			offsetof(struct fgraph_ret_regs, regs[7]));

  DEFINE(FGRET_REGS_FP,			offsetof(struct fgraph_ret_regs, fp));

  DEFINE(FGRET_REGS_SIZE,		sizeof(struct fgraph_ret_regs));

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

  DEFINE(FTRACE_OPS_DIRECT_CALL,	offsetof(struct ftrace_ops, direct_call));

#endif

arch/arm64/kernel/entry-ftrace.S

+14 −13
Original line number Diff line number Diff line
@@ -330,22 +330,23 @@ SYM_FUNC_END(ftrace_stub_graph) 
 */

SYM_CODE_START(return_to_handler)

	/* save return value regs */

	sub sp, sp, #64

	stp x0, x1, [sp]

	stp x2, x3, [sp, #16]

	stp x4, x5, [sp, #32]

	stp x6, x7, [sp, #48]



	mov	x0, x29			//     parent's fp

	bl	ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);

	sub sp, sp, #FGRET_REGS_SIZE

	stp x0, x1, [sp, #FGRET_REGS_X0]

	stp x2, x3, [sp, #FGRET_REGS_X2]

	stp x4, x5, [sp, #FGRET_REGS_X4]

	stp x6, x7, [sp, #FGRET_REGS_X6]

	str x29,    [sp, #FGRET_REGS_FP]	// parent's fp



	mov	x0, sp

	bl	ftrace_return_to_handler	// addr = ftrace_return_to_hander(regs);

	mov	x30, x0				// restore the original return address



	/* restore return value regs */

	ldp x0, x1, [sp]

	ldp x2, x3, [sp, #16]

	ldp x4, x5, [sp, #32]

	ldp x6, x7, [sp, #48]

	add sp, sp, #64

	ldp x0, x1, [sp, #FGRET_REGS_X0]

	ldp x2, x3, [sp, #FGRET_REGS_X2]

	ldp x4, x5, [sp, #FGRET_REGS_X4]

	ldp x6, x7, [sp, #FGRET_REGS_X6]

	add sp, sp, #FGRET_REGS_SIZE



	ret

SYM_CODE_END(return_to_handler)