/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2017 Andes Technology Corporation */
#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/export.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/ftrace.h>
.text
#define FENTRY_RA_OFFSET 8
#define ABI_SIZE_ON_STACK 80
#define ABI_A0 0
#define ABI_A1 8
#define ABI_A2 16
#define ABI_A3 24
#define ABI_A4 32
#define ABI_A5 40
#define ABI_A6 48
#define ABI_A7 56
#define ABI_T0 64
#define ABI_RA 72
.macro SAVE_ABI
addi sp, sp, -ABI_SIZE_ON_STACK
REG_S a0, ABI_A0(sp)
REG_S a1, ABI_A1(sp)
REG_S a2, ABI_A2(sp)
REG_S a3, ABI_A3(sp)
REG_S a4, ABI_A4(sp)
REG_S a5, ABI_A5(sp)
REG_S a6, ABI_A6(sp)
REG_S a7, ABI_A7(sp)
REG_S t0, ABI_T0(sp)
REG_S ra, ABI_RA(sp)
.endm
.macro RESTORE_ABI
REG_L a0, ABI_A0(sp)
REG_L a1, ABI_A1(sp)
REG_L a2, ABI_A2(sp)
REG_L a3, ABI_A3(sp)
REG_L a4, ABI_A4(sp)
REG_L a5, ABI_A5(sp)
REG_L a6, ABI_A6(sp)
REG_L a7, ABI_A7(sp)
REG_L t0, ABI_T0(sp)
REG_L ra, ABI_RA(sp)
addi sp, sp, ABI_SIZE_ON_STACK
.endm
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
/**
* SAVE_ABI_REGS - save regs against the ftrace_regs struct
*
* After the stack is established,
*
* 0(sp) stores the PC of the traced function which can be accessed
* by &(fregs)->epc in tracing function. Note that the real
* function entry address should be computed with -FENTRY_RA_OFFSET.
*
* 8(sp) stores the function return address (i.e. parent IP) that
* can be accessed by &(fregs)->ra in tracing function.
*
* The other regs are saved at the respective localtion and accessed
* by the respective ftrace_regs member.
*
* Here is the layout of stack for your reference.
*
* PT_SIZE_ON_STACK -> +++++++++
* + ..... +
* + a0-a7 + --++++-> ftrace_caller saved
* + t1 + --++++-> direct tramp address
* + s0 + --+ // frame pointer
* + sp + +
* + ra + --+ // parent IP
* sp -> + epc + --+ // PC
* +++++++++
**/
.macro SAVE_ABI_REGS
mv t4, sp // Save original SP in T4
addi sp, sp, -FREGS_SIZE_ON_STACK
REG_S t0, FREGS_EPC(sp)
REG_S x1, FREGS_RA(sp)
REG_S t4, FREGS_SP(sp) // Put original SP on stack
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
REG_S x8, FREGS_S0(sp)
#endif
REG_S x6, FREGS_T1(sp)
// save the arguments
REG_S x10, FREGS_A0(sp)
REG_S x11, FREGS_A1(sp)
REG_S x12, FREGS_A2(sp)
REG_S x13, FREGS_A3(sp)
REG_S x14, FREGS_A4(sp)
REG_S x15, FREGS_A5(sp)
REG_S x16, FREGS_A6(sp)
REG_S x17, FREGS_A7(sp)
.endm
.macro RESTORE_ABI_REGS, all=0
REG_L t0, FREGS_EPC(sp)
REG_L x1, FREGS_RA(sp)
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
REG_L x8, FREGS_S0(sp)
#endif
REG_L x6, FREGS_T1(sp)
// restore the arguments
REG_L x10, FREGS_A0(sp)
REG_L x11, FREGS_A1(sp)
REG_L x12, FREGS_A2(sp)
REG_L x13, FREGS_A3(sp)
REG_L x14, FREGS_A4(sp)
REG_L x15, FREGS_A5(sp)
REG_L x16, FREGS_A6(sp)
REG_L x17, FREGS_A7(sp)
addi sp, sp, FREGS_SIZE_ON_STACK
.endm
.macro PREPARE_ARGS
addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
mv a1, ra
mv a3, sp
.endm
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
SYM_FUNC_START(ftrace_caller)
SAVE_ABI
addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
mv a1, ra
mv a3, sp
SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
call ftrace_stub
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
addi a0, sp, ABI_RA
REG_L a1, ABI_T0(sp)
addi a1, a1, -FENTRY_RA_OFFSET
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a2, s0
#endif
SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
call ftrace_stub
#endif
RESTORE_ABI
jr t0
SYM_FUNC_END(ftrace_caller)
#else /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
SYM_FUNC_START(ftrace_caller)
mv t1, zero
SAVE_ABI_REGS
PREPARE_ARGS
SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
call ftrace_stub
RESTORE_ABI_REGS
bnez t1, .Ldirect
jr t0
.Ldirect:
jr t1
SYM_FUNC_END(ftrace_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
SYM_CODE_START(ftrace_stub_direct_tramp)
jr t0
SYM_CODE_END(ftrace_stub_direct_tramp)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
Codebase Browser
linux