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 15 #define ARCH_SUPPORTS_FTRACE_OPS 1 16 #ifndef __ASSEMBLY__ 17 18 extern void *return_address(unsigned int level); 19 20 #define ftrace_return_address(n) return_address(n) 21 22 void _mcount(void); 23 unsigned long ftrace_call_adjust(unsigned long addr); 24 unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip); 25 #define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) 26 27 /* 28 * Let's do like x86/arm64 and ignore the compat syscalls. 29 */ 30 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 31 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) 32 { 33 return is_compat_task(); 34 } 35 36 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME 37 static inline bool arch_syscall_match_sym_name(const char *sym, 38 const char *name) 39 { 40 /* 41 * Since all syscall functions have __riscv_ prefix, we must skip it. 42 * However, as we described above, we decided to ignore compat 43 * syscalls, so we don't care about __riscv_compat_ prefix here. 44 */ 45 return !strcmp(sym + 8, name); 46 } 47 48 struct dyn_arch_ftrace { 49 }; 50 #endif 51 52 #ifdef CONFIG_DYNAMIC_FTRACE 53 /* 54 * A general call in RISC-V is a pair of insts: 55 * 1) auipc: setting high-20 pc-related bits to ra register 56 * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to 57 * return address (original pc + 4) 58 * 59 * The first 2 instructions for each tracable function is compiled to 2 nop 60 * instructions. Then, the kernel initializes the first instruction to auipc at 61 * boot time (<ftrace disable>). The second instruction is patched to jalr to 62 * start the trace. 63 * 64 *<Image>: 65 * 0: nop 66 * 4: nop 67 * 68 *<ftrace enable>: 69 * 0: auipc t0, 0x? 70 * 4: jalr t0, ?(t0) 71 * 72 *<ftrace disable>: 73 * 0: auipc t0, 0x? 74 * 4: nop 75 * 76 * Dynamic ftrace generates probes to call sites, so we must deal with 77 * both auipc and jalr at the same time. 78 */ 79 80 #define MCOUNT_ADDR ((unsigned long)_mcount) 81 #define JALR_SIGN_MASK (0x00000800) 82 #define JALR_OFFSET_MASK (0x00000fff) 83 #define AUIPC_OFFSET_MASK (0xfffff000) 84 #define AUIPC_PAD (0x00001000) 85 #define JALR_SHIFT 20 86 #define JALR_T0 (0x000282e7) 87 #define AUIPC_T0 (0x00000297) 88 #define JALR_RANGE (JALR_SIGN_MASK - 1) 89 90 #define to_jalr_t0(offset) \ 91 (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0) 92 93 #define to_auipc_t0(offset) \ 94 ((offset & JALR_SIGN_MASK) ? \ 95 (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) : \ 96 ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0)) 97 98 #define make_call_t0(caller, callee, call) \ 99 do { \ 100 unsigned int offset = \ 101 (unsigned long) (callee) - (unsigned long) (caller); \ 102 call[0] = to_auipc_t0(offset); \ 103 call[1] = to_jalr_t0(offset); \ 104 } while (0) 105 106 /* 107 * Only the jalr insn in the auipc+jalr is patched, so we make it 4 108 * bytes here. 109 */ 110 #define MCOUNT_INSN_SIZE 4 111 #define MCOUNT_AUIPC_SIZE 4 112 #define MCOUNT_JALR_SIZE 4 113 #define MCOUNT_NOP4_SIZE 4 114 115 #ifndef __ASSEMBLY__ 116 struct dyn_ftrace; 117 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); 118 #define ftrace_init_nop ftrace_init_nop 119 120 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS 121 #define arch_ftrace_get_regs(regs) NULL 122 #define HAVE_ARCH_FTRACE_REGS 123 struct ftrace_ops; 124 struct ftrace_regs; 125 #define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs)) 126 127 struct __arch_ftrace_regs { 128 unsigned long epc; 129 unsigned long ra; 130 unsigned long sp; 131 unsigned long s0; 132 unsigned long t1; 133 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 134 unsigned long direct_tramp; 135 #endif 136 union { 137 unsigned long args[8]; 138 struct { 139 unsigned long a0; 140 unsigned long a1; 141 unsigned long a2; 142 unsigned long a3; 143 unsigned long a4; 144 unsigned long a5; 145 unsigned long a6; 146 unsigned long a7; 147 #ifdef CONFIG_CC_IS_CLANG 148 unsigned long t2; 149 unsigned long t3; 150 unsigned long t4; 151 unsigned long t5; 152 unsigned long t6; 153 #endif 154 }; 155 }; 156 }; 157 158 static __always_inline unsigned long ftrace_regs_get_instruction_pointer(const struct ftrace_regs 159 *fregs) 160 { 161 return arch_ftrace_regs(fregs)->epc; 162 } 163 164 static __always_inline void ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, 165 unsigned long pc) 166 { 167 arch_ftrace_regs(fregs)->epc = pc; 168 } 169 170 static __always_inline unsigned long ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs) 171 { 172 return arch_ftrace_regs(fregs)->sp; 173 } 174 175 static __always_inline unsigned long ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs) 176 { 177 return arch_ftrace_regs(fregs)->s0; 178 } 179 180 static __always_inline unsigned long ftrace_regs_get_argument(struct ftrace_regs *fregs, 181 unsigned int n) 182 { 183 if (n < 8) 184 return arch_ftrace_regs(fregs)->args[n]; 185 return 0; 186 } 187 188 static __always_inline unsigned long ftrace_regs_get_return_value(const struct ftrace_regs *fregs) 189 { 190 return arch_ftrace_regs(fregs)->a0; 191 } 192 193 static __always_inline unsigned long ftrace_regs_get_return_address(const struct ftrace_regs *fregs) 194 { 195 return arch_ftrace_regs(fregs)->ra; 196 } 197 198 static __always_inline void ftrace_regs_set_return_value(struct ftrace_regs *fregs, 199 unsigned long ret) 200 { 201 arch_ftrace_regs(fregs)->a0 = ret; 202 } 203 204 static __always_inline void ftrace_override_function_with_return(struct ftrace_regs *fregs) 205 { 206 arch_ftrace_regs(fregs)->epc = arch_ftrace_regs(fregs)->ra; 207 } 208 209 static __always_inline struct pt_regs * 210 ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) 211 { 212 struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs); 213 214 memcpy(®s->a_regs, afregs->args, sizeof(afregs->args)); 215 regs->epc = afregs->epc; 216 regs->ra = afregs->ra; 217 regs->sp = afregs->sp; 218 regs->s0 = afregs->s0; 219 regs->t1 = afregs->t1; 220 return regs; 221 } 222 223 int ftrace_regs_query_register_offset(const char *name); 224 225 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 226 struct ftrace_ops *op, struct ftrace_regs *fregs); 227 #define ftrace_graph_func ftrace_graph_func 228 229 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 230 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr) 231 { 232 arch_ftrace_regs(fregs)->t1 = addr; 233 } 234 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ 235 236 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */ 237 238 #endif /* __ASSEMBLY__ */ 239 240 #endif /* CONFIG_DYNAMIC_FTRACE */ 241 242 #endif /* _ASM_RISCV_FTRACE_H */ 243