arch/riscv/include/asm/ftrace.h

   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 #define ARCH_SUPPORTS_FTRACE_OPS 1
  17 #ifndef __ASSEMBLY__
  18 void _mcount(void);
  19 static inline unsigned long ftrace_call_adjust(unsigned long addr)
  20 {
  21         return addr;
  22 }
  23
  24 struct dyn_arch_ftrace {
  25 };
  26 #endif
  27
  28 #ifdef CONFIG_DYNAMIC_FTRACE
  29 /*
  30  * A general call in RISC-V is a pair of insts:
  31  * 1) auipc: setting high-20 pc-related bits to ra register
  32  * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
  33  *          return address (original pc + 4)
  34  *
  35  * Dynamic ftrace generates probes to call sites, so we must deal with
  36  * both auipc and jalr at the same time.
  37  */
  38
  39 #define MCOUNT_ADDR             ((unsigned long)_mcount)
  40 #define JALR_SIGN_MASK          (0x00000800)
  41 #define JALR_OFFSET_MASK        (0x00000fff)
  42 #define AUIPC_OFFSET_MASK       (0xfffff000)
  43 #define AUIPC_PAD               (0x00001000)
  44 #define JALR_SHIFT              20
  45 #define JALR_BASIC              (0x000080e7)
  46 #define AUIPC_BASIC             (0x00000097)
  47 #define NOP4                    (0x00000013)
  48
  49 #define make_call(caller, callee, call)                                 \
  50 do {                                                                    \
  51         call[0] = to_auipc_insn((unsigned int)((unsigned long)callee -  \
  52                                 (unsigned long)caller));                \
  53         call[1] = to_jalr_insn((unsigned int)((unsigned long)callee -   \
  54                                (unsigned long)caller));                 \
  55 } while (0)
  56
  57 #define to_jalr_insn(offset)                                            \
  58         (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC)
  59
  60 #define to_auipc_insn(offset)                                           \
  61         ((offset & JALR_SIGN_MASK) ?                                    \
  62         (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) :    \
  63         ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC))
  64
  65 /*
  66  * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
  67  */
  68 #define MCOUNT_INSN_SIZE 8
  69 #endif
  70
  71 #endif /* _ASM_RISCV_FTRACE_H */