/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2017 Andes Technology Corporation */
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/asm.h>
#include <asm/csr.h>
#include <asm/unistd.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm-generic/export.h>
#include <asm/ftrace.h>
.text
.macro SAVE_ABI_STATE
addi sp, sp, -16
sd s0, 0(sp)
sd ra, 8(sp)
addi s0, sp, 16
.endm
/*
* The call to ftrace_return_to_handler would overwrite the return
* register if a0 was not saved.
*/
.macro SAVE_RET_ABI_STATE
addi sp, sp, -32
sd s0, 16(sp)
sd ra, 24(sp)
sd a0, 8(sp)
addi s0, sp, 32
.endm
.macro RESTORE_ABI_STATE
ld ra, 8(sp)
ld s0, 0(sp)
addi sp, sp, 16
.endm
.macro RESTORE_RET_ABI_STATE
ld ra, 24(sp)
ld s0, 16(sp)
ld a0, 8(sp)
addi sp, sp, 32
.endm
ENTRY(ftrace_stub)
#ifdef CONFIG_DYNAMIC_FTRACE
.global _mcount
.set _mcount, ftrace_stub
#endif
ret
ENDPROC(ftrace_stub)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(return_to_handler)
/*
* On implementing the frame point test, the ideal way is to compare the
* s0 (frame pointer, if enabled) on entry and the sp (stack pointer) on return.
* However, the psABI of variable-length-argument functions does not allow this.
*
* So alternatively we check the *old* frame pointer position, that is, the
* value stored in -16(s0) on entry, and the s0 on return.
*/
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv t6, s0
#endif
SAVE_RET_ABI_STATE
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a0, t6
#endif
call ftrace_return_to_handler
mv a1, a0
RESTORE_RET_ABI_STATE
jalr a1
ENDPROC(return_to_handler)
#endif
#ifndef CONFIG_DYNAMIC_FTRACE
ENTRY(_mcount)
la t4, ftrace_stub
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
la t0, ftrace_graph_return
ld t1, 0(t0)
bne t1, t4, do_ftrace_graph_caller
la t3, ftrace_graph_entry
ld t2, 0(t3)
la t6, ftrace_graph_entry_stub
bne t2, t6, do_ftrace_graph_caller
#endif
la t3, ftrace_trace_function
ld t5, 0(t3)
bne t5, t4, do_trace
ret
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* A pseudo representation for the function graph tracer:
* prepare_to_return(&ra_to_caller_of_caller, ra_to_caller)
*/
do_ftrace_graph_caller:
addi a0, s0, -8
mv a1, ra
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
ld a2, -16(s0)
#endif
SAVE_ABI_STATE
call prepare_ftrace_return
RESTORE_ABI_STATE
ret
#endif
/*
* A pseudo representation for the function tracer:
* (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)
*/
do_trace:
ld a1, -8(s0)
mv a0, ra
SAVE_ABI_STATE
jalr t5
RESTORE_ABI_STATE
ret
ENDPROC(_mcount)
#endif
EXPORT_SYMBOL(_mcount)
