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
19extern void *return_address(unsigned int level);
20
21#define ftrace_return_address(n) return_address(n)
22
23void _mcount(void);
24static inline unsigned long ftrace_call_adjust(unsigned long addr)
25{
26	return addr;
27}
28
29/*
30 * Let's do like x86/arm64 and ignore the compat syscalls.
31 */
32#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
33static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
34{
35	return is_compat_task();
36}
37
38#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
39static inline bool arch_syscall_match_sym_name(const char *sym,
40					       const char *name)
41{
42	/*
43	 * Since all syscall functions have __riscv_ prefix, we must skip it.
44	 * However, as we described above, we decided to ignore compat
45	 * syscalls, so we don't care about __riscv_compat_ prefix here.
46	 */
47	return !strcmp(sym + 8, name);
48}
49
50struct dyn_arch_ftrace {
51};
52#endif
53
54#ifdef CONFIG_DYNAMIC_FTRACE
55/*
56 * A general call in RISC-V is a pair of insts:
57 * 1) auipc: setting high-20 pc-related bits to ra register
58 * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
59 *          return address (original pc + 4)
60 *
61 *<ftrace enable>:
62 * 0: auipc  t0/ra, 0x?
63 * 4: jalr   t0/ra, ?(t0/ra)
64 *
65 *<ftrace disable>:
66 * 0: nop
67 * 4: nop
68 *
69 * Dynamic ftrace generates probes to call sites, so we must deal with
70 * both auipc and jalr at the same time.
71 */
72
73#define MCOUNT_ADDR		((unsigned long)_mcount)
74#define JALR_SIGN_MASK		(0x00000800)
75#define JALR_OFFSET_MASK	(0x00000fff)
76#define AUIPC_OFFSET_MASK	(0xfffff000)
77#define AUIPC_PAD		(0x00001000)
78#define JALR_SHIFT		20
79#define JALR_RA			(0x000080e7)
80#define AUIPC_RA		(0x00000097)
81#define JALR_T0			(0x000282e7)
82#define AUIPC_T0		(0x00000297)
83#define NOP4			(0x00000013)
84
85#define to_jalr_t0(offset)						\
86	(((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0)
87
88#define to_auipc_t0(offset)						\
89	((offset & JALR_SIGN_MASK) ?					\
90	(((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) :	\
91	((offset & AUIPC_OFFSET_MASK) | AUIPC_T0))
92
93#define make_call_t0(caller, callee, call)				\
94do {									\
95	unsigned int offset =						\
96		(unsigned long) callee - (unsigned long) caller;	\
97	call[0] = to_auipc_t0(offset);					\
98	call[1] = to_jalr_t0(offset);					\
99} while (0)
100
101#define to_jalr_ra(offset)						\
102	(((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_RA)
103
104#define to_auipc_ra(offset)						\
105	((offset & JALR_SIGN_MASK) ?					\
106	(((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_RA) :	\
107	((offset & AUIPC_OFFSET_MASK) | AUIPC_RA))
108
109#define make_call_ra(caller, callee, call)				\
110do {									\
111	unsigned int offset =						\
112		(unsigned long) callee - (unsigned long) caller;	\
113	call[0] = to_auipc_ra(offset);					\
114	call[1] = to_jalr_ra(offset);					\
115} while (0)
116
117/*
118 * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
119 */
120#define MCOUNT_INSN_SIZE 8
121
122#ifndef __ASSEMBLY__
123struct dyn_ftrace;
124int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
125#define ftrace_init_nop ftrace_init_nop
126
127#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
128struct ftrace_ops;
129struct ftrace_regs;
130void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
131		       struct ftrace_ops *op, struct ftrace_regs *fregs);
132#define ftrace_graph_func ftrace_graph_func
133
134static inline void __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
135{
136		regs->t1 = addr;
137}
138#define arch_ftrace_set_direct_caller(fregs, addr) \
139	__arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
140#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
141
142#endif /* __ASSEMBLY__ */
143
144#endif /* CONFIG_DYNAMIC_FTRACE */
145
146#ifndef __ASSEMBLY__
147#ifdef CONFIG_FUNCTION_GRAPH_TRACER
148struct fgraph_ret_regs {
149	unsigned long a1;
150	unsigned long a0;
151	unsigned long s0;
152	unsigned long ra;
153};
154
155static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
156{
157	return ret_regs->a0;
158}
159
160static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
161{
162	return ret_regs->s0;
163}
164#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */
165#endif
166
167#endif /* _ASM_RISCV_FTRACE_H */
168