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