1 #ifndef _ASM_POWERPC_CODE_PATCHING_H 2 #define _ASM_POWERPC_CODE_PATCHING_H 3 4 /* 5 * Copyright 2008, Michael Ellerman, IBM Corporation. 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 */ 12 13 #include <asm/types.h> 14 #include <asm/ppc-opcode.h> 15 16 /* Flags for create_branch: 17 * "b" == create_branch(addr, target, 0); 18 * "ba" == create_branch(addr, target, BRANCH_ABSOLUTE); 19 * "bl" == create_branch(addr, target, BRANCH_SET_LINK); 20 * "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK); 21 */ 22 #define BRANCH_SET_LINK 0x1 23 #define BRANCH_ABSOLUTE 0x2 24 25 unsigned int create_branch(const unsigned int *addr, 26 unsigned long target, int flags); 27 unsigned int create_cond_branch(const unsigned int *addr, 28 unsigned long target, int flags); 29 int patch_branch(unsigned int *addr, unsigned long target, int flags); 30 int patch_instruction(unsigned int *addr, unsigned int instr); 31 32 int instr_is_relative_branch(unsigned int instr); 33 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr); 34 unsigned long branch_target(const unsigned int *instr); 35 unsigned int translate_branch(const unsigned int *dest, 36 const unsigned int *src); 37 #ifdef CONFIG_PPC_BOOK3E_64 38 void __patch_exception(int exc, unsigned long addr); 39 #define patch_exception(exc, name) do { \ 40 extern unsigned int name; \ 41 __patch_exception((exc), (unsigned long)&name); \ 42 } while (0) 43 #endif 44 45 #define OP_RT_RA_MASK 0xffff0000UL 46 #define LIS_R2 0x3c020000UL 47 #define ADDIS_R2_R12 0x3c4c0000UL 48 #define ADDI_R2_R2 0x38420000UL 49 50 static inline unsigned long ppc_function_entry(void *func) 51 { 52 #ifdef PPC64_ELF_ABI_v2 53 u32 *insn = func; 54 55 /* 56 * A PPC64 ABIv2 function may have a local and a global entry 57 * point. We need to use the local entry point when patching 58 * functions, so identify and step over the global entry point 59 * sequence. 60 * 61 * The global entry point sequence is always of the form: 62 * 63 * addis r2,r12,XXXX 64 * addi r2,r2,XXXX 65 * 66 * A linker optimisation may convert the addis to lis: 67 * 68 * lis r2,XXXX 69 * addi r2,r2,XXXX 70 */ 71 if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) || 72 ((*insn & OP_RT_RA_MASK) == LIS_R2)) && 73 ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2)) 74 return (unsigned long)(insn + 2); 75 else 76 return (unsigned long)func; 77 #elif defined(PPC64_ELF_ABI_v1) 78 /* 79 * On PPC64 ABIv1 the function pointer actually points to the 80 * function's descriptor. The first entry in the descriptor is the 81 * address of the function text. 82 */ 83 return ((func_descr_t *)func)->entry; 84 #else 85 return (unsigned long)func; 86 #endif 87 } 88 89 static inline unsigned long ppc_global_function_entry(void *func) 90 { 91 #ifdef PPC64_ELF_ABI_v2 92 /* PPC64 ABIv2 the global entry point is at the address */ 93 return (unsigned long)func; 94 #else 95 /* All other cases there is no change vs ppc_function_entry() */ 96 return ppc_function_entry(func); 97 #endif 98 } 99 100 #ifdef CONFIG_PPC64 101 /* 102 * Some instruction encodings commonly used in dynamic ftracing 103 * and function live patching. 104 */ 105 106 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */ 107 #ifdef PPC64_ELF_ABI_v2 108 #define R2_STACK_OFFSET 24 109 #else 110 #define R2_STACK_OFFSET 40 111 #endif 112 113 #define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \ 114 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET) 115 116 /* usually preceded by a mflr r0 */ 117 #define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \ 118 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF) 119 #endif /* CONFIG_PPC64 */ 120 121 #endif /* _ASM_POWERPC_CODE_PATCHING_H */ 122