xref: /linux/arch/riscv/include/asm/ftrace.h (revision 87c9c16317882dd6dbbc07e349bc3223e14f3244)
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);
29 static inline unsigned long ftrace_call_adjust(unsigned long addr)
30 {
31 	return addr;
32 }
33 
34 struct dyn_arch_ftrace {
35 };
36 #endif
37 
38 #ifdef CONFIG_DYNAMIC_FTRACE
39 /*
40  * A general call in RISC-V is a pair of insts:
41  * 1) auipc: setting high-20 pc-related bits to ra register
42  * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
43  *          return address (original pc + 4)
44  *
45  * Dynamic ftrace generates probes to call sites, so we must deal with
46  * both auipc and jalr at the same time.
47  */
48 
49 #define MCOUNT_ADDR		((unsigned long)MCOUNT_NAME)
50 #define JALR_SIGN_MASK		(0x00000800)
51 #define JALR_OFFSET_MASK	(0x00000fff)
52 #define AUIPC_OFFSET_MASK	(0xfffff000)
53 #define AUIPC_PAD		(0x00001000)
54 #define JALR_SHIFT		20
55 #define JALR_BASIC		(0x000080e7)
56 #define AUIPC_BASIC		(0x00000097)
57 #define NOP4			(0x00000013)
58 
59 #define make_call(caller, callee, call)					\
60 do {									\
61 	call[0] = to_auipc_insn((unsigned int)((unsigned long)callee -	\
62 				(unsigned long)caller));		\
63 	call[1] = to_jalr_insn((unsigned int)((unsigned long)callee -	\
64 			       (unsigned long)caller));			\
65 } while (0)
66 
67 #define to_jalr_insn(offset)						\
68 	(((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC)
69 
70 #define to_auipc_insn(offset)						\
71 	((offset & JALR_SIGN_MASK) ?					\
72 	(((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) :	\
73 	((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC))
74 
75 /*
76  * Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
77  */
78 #define MCOUNT_INSN_SIZE 8
79 
80 #ifndef __ASSEMBLY__
81 struct dyn_ftrace;
82 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
83 #define ftrace_init_nop ftrace_init_nop
84 #endif
85 
86 #endif
87 
88 #endif /* _ASM_RISCV_FTRACE_H */
89