Commit a51ac524 authored by Qing Zhang's avatar Qing Zhang Committed by Huacai Chen
Browse files

LoongArch/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support 



ftrace_graph_ret_addr() can be called by stack unwinding code to convert
a found stack return address ('ret') to its original value, in case the
function graph tracer has modified it to be 'return_to_handler'. If the
hasn't been modified, the unchanged value of 'ret' is returned.

Signed-off-by: default avatarQing Zhang <zhangqing@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent ac7127e1

arch/loongarch/include/asm/ftrace.h

+3 −0
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ 
#ifndef _ASM_LOONGARCH_FTRACE_H

#define _ASM_LOONGARCH_FTRACE_H



#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))



#ifdef CONFIG_FUNCTION_TRACER



#define MCOUNT_INSN_SIZE 4		/* sizeof mcount call */
@@ -24,6 +26,7 @@ struct dyn_ftrace; 
struct dyn_arch_ftrace { };



#define ARCH_SUPPORTS_FTRACE_OPS 1

#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR



#define ftrace_init_nop ftrace_init_nop

int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);

arch/loongarch/include/asm/unwind.h

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ struct unwind_state { 
	struct stack_info stack_info;

	struct task_struct *task;

	bool first, error, is_ftrace;

	int graph_idx;

	unsigned long sp, pc, ra;

};

arch/loongarch/kernel/ftrace_dyn.c

+1 −1
Original line number Diff line number Diff line
@@ -135,7 +135,7 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent) 


	old = *parent;



	if (!function_graph_enter(old, self_addr, 0, NULL))

	if (!function_graph_enter(old, self_addr, 0, parent))

		*parent = return_hooker;

}

arch/loongarch/kernel/unwind_guess.c

+3 −1
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 * Copyright (C) 2022 Loongson Technology Corporation Limited

 */

#include <linux/kernel.h>

#include <linux/ftrace.h>



#include <asm/unwind.h>
@@ -53,7 +54,8 @@ bool unwind_next_frame(struct unwind_state *state) 
		     state->sp < info->end;

		     state->sp += sizeof(unsigned long)) {

			addr = *(unsigned long *)(state->sp);



			state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

					addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));

			if (__kernel_text_address(addr))

				return true;

		}

arch/loongarch/kernel/unwind_prologue.c

+11 −4
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
/*

 * Copyright (C) 2022 Loongson Technology Corporation Limited

 */

#include <linux/ftrace.h>

#include <linux/kallsyms.h>



#include <asm/inst.h>
@@ -42,6 +43,8 @@ static bool unwind_by_guess(struct unwind_state *state) 
	     state->sp < info->end;

	     state->sp += sizeof(unsigned long)) {

		addr = *(unsigned long *)(state->sp);

		state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

				addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));

		if (__kernel_text_address(addr))

			return true;

	}
@@ -174,8 +177,11 @@ bool unwind_next_frame(struct unwind_state *state) 
			break;



		case UNWINDER_PROLOGUE:

			if (unwind_by_prologue(state))

			if (unwind_by_prologue(state)) {

				state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

						state->pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));

				return true;

			}



			if (info->type == STACK_TYPE_IRQ &&

				info->end == state->sp) {
@@ -185,10 +191,11 @@ bool unwind_next_frame(struct unwind_state *state) 
				if (user_mode(regs) || !__kernel_text_address(pc))

					return false;



				state->pc = pc;

				state->sp = regs->regs[3];

				state->ra = regs->regs[1];

				state->first = true;

				state->ra = regs->regs[1];

				state->sp = regs->regs[3];

				state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

						pc, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));

				get_stack_info(state->sp, state->task, info);



				return true;