1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 #ifndef _ASM_POWERPC_CODE_PATCHING_H
3 #define _ASM_POWERPC_CODE_PATCHING_H
6 * Copyright 2008, Michael Ellerman, IBM Corporation.
10 #include <asm/ppc-opcode.h>
11 #include <linux/string.h>
12 #include <linux/kallsyms.h>
13 #include <asm/asm-compat.h>
15 /* Flags for create_branch:
16 * "b" == create_branch(addr, target, 0);
17 * "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
18 * "bl" == create_branch(addr, target, BRANCH_SET_LINK);
19 * "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
21 #define BRANCH_SET_LINK 0x1
22 #define BRANCH_ABSOLUTE 0x2
24 bool is_offset_in_branch_range(long offset);
25 bool is_offset_in_cond_branch_range(long offset);
26 unsigned int create_branch(const unsigned int *addr,
27 unsigned long target, int flags);
28 unsigned int create_cond_branch(const unsigned int *addr,
29 unsigned long target, int flags);
30 int patch_branch(unsigned int *addr, unsigned long target, int flags);
31 int patch_instruction(unsigned int *addr, unsigned int instr);
32 int raw_patch_instruction(unsigned int *addr, unsigned int instr);
34 static inline unsigned long patch_site_addr(s32 *site)
36 return (unsigned long)site + *site;
39 static inline int patch_instruction_site(s32 *site, unsigned int instr)
41 return patch_instruction((unsigned int *)patch_site_addr(site), instr);
44 static inline int patch_branch_site(s32 *site, unsigned long target, int flags)
46 return patch_branch((unsigned int *)patch_site_addr(site), target, flags);
49 static inline int modify_instruction(unsigned int *addr, unsigned int clr,
52 return patch_instruction(addr, (*addr & ~clr) | set);
55 static inline int modify_instruction_site(s32 *site, unsigned int clr, unsigned int set)
57 return modify_instruction((unsigned int *)patch_site_addr(site), clr, set);
60 int instr_is_relative_branch(unsigned int instr);
61 int instr_is_relative_link_branch(unsigned int instr);
62 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
63 unsigned long branch_target(const unsigned int *instr);
64 unsigned int translate_branch(const unsigned int *dest,
65 const unsigned int *src);
66 extern bool is_conditional_branch(unsigned int instr);
67 #ifdef CONFIG_PPC_BOOK3E_64
68 void __patch_exception(int exc, unsigned long addr);
69 #define patch_exception(exc, name) do { \
70 extern unsigned int name; \
71 __patch_exception((exc), (unsigned long)&name); \
75 #define OP_RT_RA_MASK 0xffff0000UL
76 #define LIS_R2 0x3c400000UL
77 #define ADDIS_R2_R12 0x3c4c0000UL
78 #define ADDI_R2_R2 0x38420000UL
80 static inline unsigned long ppc_function_entry(void *func)
82 #ifdef PPC64_ELF_ABI_v2
86 * A PPC64 ABIv2 function may have a local and a global entry
87 * point. We need to use the local entry point when patching
88 * functions, so identify and step over the global entry point
91 * The global entry point sequence is always of the form:
96 * A linker optimisation may convert the addis to lis:
101 if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
102 ((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
103 ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
104 return (unsigned long)(insn + 2);
106 return (unsigned long)func;
107 #elif defined(PPC64_ELF_ABI_v1)
109 * On PPC64 ABIv1 the function pointer actually points to the
110 * function's descriptor. The first entry in the descriptor is the
111 * address of the function text.
113 return ((func_descr_t *)func)->entry;
115 return (unsigned long)func;
119 static inline unsigned long ppc_global_function_entry(void *func)
121 #ifdef PPC64_ELF_ABI_v2
122 /* PPC64 ABIv2 the global entry point is at the address */
123 return (unsigned long)func;
125 /* All other cases there is no change vs ppc_function_entry() */
126 return ppc_function_entry(func);
131 * Wrapper around kallsyms_lookup() to return function entry address:
132 * - For ABIv1, we lookup the dot variant.
133 * - For ABIv2, we return the local entry point.
135 static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
138 #ifdef PPC64_ELF_ABI_v1
139 /* check for dot variant */
140 char dot_name[1 + KSYM_NAME_LEN];
141 bool dot_appended = false;
143 if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)
146 if (name[0] != '.') {
149 strlcat(dot_name, name, sizeof(dot_name));
153 strlcat(dot_name, name, sizeof(dot_name));
155 addr = kallsyms_lookup_name(dot_name);
156 if (!addr && dot_appended)
157 /* Let's try the original non-dot symbol lookup */
158 addr = kallsyms_lookup_name(name);
159 #elif defined(PPC64_ELF_ABI_v2)
160 addr = kallsyms_lookup_name(name);
162 addr = ppc_function_entry((void *)addr);
164 addr = kallsyms_lookup_name(name);
171 * Some instruction encodings commonly used in dynamic ftracing
172 * and function live patching.
175 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
176 #ifdef PPC64_ELF_ABI_v2
177 #define R2_STACK_OFFSET 24
179 #define R2_STACK_OFFSET 40
182 #define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
183 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
185 /* usually preceded by a mflr r0 */
186 #define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
187 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
188 #endif /* CONFIG_PPC64 */
190 #endif /* _ASM_POWERPC_CODE_PATCHING_H */