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 /*
  25  * Let's do like x86/arm64 and ignore the compat syscalls.
  26  */
  27 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
  28 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
  29 {
  30         return is_compat_task();
  31 }
  32
  33 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
  34 static inline bool arch_syscall_match_sym_name(const char *sym,
  35                                                const char *name)
  36 {
  37         /*
  38          * Since all syscall functions have __riscv_ prefix, we must skip it.
  39          * However, as we described above, we decided to ignore compat
  40          * syscalls, so we don't care about __riscv_compat_ prefix here.
  41          */
  42         return !strcmp(sym + 8, name);
  43 }
  44
  45 struct dyn_arch_ftrace {
  46 };
  47 #endif
  48
  49 #ifdef CONFIG_DYNAMIC_FTRACE
  50 /*
  51  * A general call in RISC-V is a pair of insts:
  52  * 1) auipc: setting high-20 pc-related bits to ra register
  53  * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
  54  *          return address (original pc + 4)
  55  *
  56  *<ftrace enable>:
  57  * 0: auipc  t0/ra, 0x?
  58  * 4: jalr   t0/ra, ?(t0/ra)
  59  *
  60  *<ftrace disable>:
  61  * 0: nop
  62  * 4: nop
  63  *
  64  * Dynamic ftrace generates probes to call sites, so we must deal with
  65  * both auipc and jalr at the same time.
  66  */
  67
  68 #define MCOUNT_ADDR             ((unsigned long)_mcount)
  69 #define JALR_SIGN_MASK          (0x00000800)
  70 #define JALR_OFFSET_MASK        (0x00000fff)
  71 #define AUIPC_OFFSET_MASK       (0xfffff000)
  72 #define AUIPC_PAD               (0x00001000)
  73 #define JALR_SHIFT              20
  74 #define JALR_RA                 (0x000080e7)
  75 #define AUIPC_RA                (0x00000097)
  76 #define JALR_T0                 (0x000282e7)
  77 #define AUIPC_T0                (0x00000297)
  78 #define NOP4                    (0x00000013)
  79
  80 #define to_jalr_t0(offset)                                              \
  81         (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0)
  82
  83 #define to_auipc_t0(offset)                                             \
  84         ((offset & JALR_SIGN_MASK) ?                                    \
  85         (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) :       \
  86         ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0))
  87
  88 #define make_call_t0(caller, callee, call)                              \
  89 do {                                                                    \
  90         unsigned int offset =                                           \
  91                 (unsigned long) callee - (unsigned long) caller;        \
  92         call[0] = to_auipc_t0(offset);                                  \
  93         call[1] = to_jalr_t0(offset);                                   \
  94 } while (0)
  95
  96 #define to_jalr_ra(offset)                                              \
  97         (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_RA)
  98
  99 #define to_auipc_ra(offset)                                             \
 100         ((offset & JALR_SIGN_MASK) ?                                    \
 101         (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_RA) :       \
 102         ((offset & AUIPC_OFFSET_MASK) | AUIPC_RA))
 103
 104 #define make_call_ra(caller, callee, call)                              \
 105 do {                                                                    \
 106         unsigned int offset =                                           \
 107                 (unsigned long) callee - (unsigned long) caller;        \
 108         call[0] = to_auipc_ra(offset);                                  \
 109         call[1] = to_jalr_ra(offset);                                   \
 110 } while (0)
 111
 112 /*
 113  * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
 114  */
 115 #define MCOUNT_INSN_SIZE 8
 116
 117 #ifndef __ASSEMBLY__
 118 struct dyn_ftrace;
 119 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 120 #define ftrace_init_nop ftrace_init_nop
 121
 122 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 123 struct ftrace_ops;
 124 struct ftrace_regs;
 125 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
 126                        struct ftrace_ops *op, struct ftrace_regs *fregs);
 127 #define ftrace_graph_func ftrace_graph_func
 128
 129 static inline void __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
 130 {
 131                 regs->t1 = addr;
 132 }
 133 #define arch_ftrace_set_direct_caller(fregs, addr) \
 134         __arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
 135 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 136
 137 #endif /* __ASSEMBLY__ */
 138
 139 #endif /* CONFIG_DYNAMIC_FTRACE */
 140
 141 #ifndef __ASSEMBLY__
 142 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 143 struct fgraph_ret_regs {
 144         unsigned long a1;
 145         unsigned long a0;
 146         unsigned long s0;
 147         unsigned long ra;
 148 };
 149
 150 static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
 151 {
 152         return ret_regs->a0;
 153 }
 154
 155 static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
 156 {
 157         return ret_regs->s0;
 158 }
 159 #endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
 160 #endif
 161
 162 #endif /* _ASM_RISCV_FTRACE_H */