linux/arch/riscv/include/asm/ftrace.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/* Copyright (C) 2017 Andes Technology Corporation */
   3
   4#ifndef _ASM_RISCV_FTRACE_H
   5#define _ASM_RISCV_FTRACE_H
   6
   7/*
   8 * The graph frame test is not possible if CONFIG_FRAME_POINTER is not enabled.
   9 * Check arch/riscv/kernel/mcount.S for detail.
  10 */
  11#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && defined(CONFIG_FRAME_POINTER)
  12#define HAVE_FUNCTION_GRAPH_FP_TEST
  13#endif
  14#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
  15
  16/*
  17 * Clang prior to 13 had "mcount" instead of "_mcount":
  18 * https://reviews.llvm.org/D98881
  19 */
  20#if defined(CONFIG_CC_IS_GCC) || CONFIG_CLANG_VERSION >= 130000
  21#define MCOUNT_NAME _mcount
  22#else
  23#define MCOUNT_NAME mcount
  24#endif
  25
  26#define ARCH_SUPPORTS_FTRACE_OPS 1
  27#ifndef __ASSEMBLY__
  28void MCOUNT_NAME(void);
  29static inline unsigned long ftrace_call_adjust(unsigned long addr)
  30{
  31        return addr;
  32}
  33
  34struct dyn_arch_ftrace {
  35};
  36#endif
  37
  38#ifdef CONFIG_DYNAMIC_FTRACE
  39/*
  40 * A general call in RISC-V is a pair of insts:
  41 * 1) auipc: setting high-20 pc-related bits to ra register
  42 * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
  43 *          return address (original pc + 4)
  44 *
  45 * Dynamic ftrace generates probes to call sites, so we must deal with
  46 * both auipc and jalr at the same time.
  47 */
  48
  49#define MCOUNT_ADDR             ((unsigned long)MCOUNT_NAME)
  50#define JALR_SIGN_MASK          (0x00000800)
  51#define JALR_OFFSET_MASK        (0x00000fff)
  52#define AUIPC_OFFSET_MASK       (0xfffff000)
  53#define AUIPC_PAD               (0x00001000)
  54#define JALR_SHIFT              20
  55#define JALR_BASIC              (0x000080e7)
  56#define AUIPC_BASIC             (0x00000097)
  57#define NOP4                    (0x00000013)
  58
  59#define make_call(caller, callee, call)                                 \
  60do {                                                                    \
  61        call[0] = to_auipc_insn((unsigned int)((unsigned long)callee -  \
  62                                (unsigned long)caller));                \
  63        call[1] = to_jalr_insn((unsigned int)((unsigned long)callee -   \
  64                               (unsigned long)caller));                 \
  65} while (0)
  66
  67#define to_jalr_insn(offset)                                            \
  68        (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC)
  69
  70#define to_auipc_insn(offset)                                           \
  71        ((offset & JALR_SIGN_MASK) ?                                    \
  72        (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) :    \
  73        ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC))
  74
  75/*
  76 * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
  77 */
  78#define MCOUNT_INSN_SIZE 8
  79
  80#ifndef __ASSEMBLY__
  81struct dyn_ftrace;
  82int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
  83#define ftrace_init_nop ftrace_init_nop
  84#endif
  85
  86#endif
  87
  88#endif /* _ASM_RISCV_FTRACE_H */
  89