arch/riscv/include/asm/ftrace.h

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