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