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 #if defined(CONFIG_PPC64) 53 #if defined(_CALL_ELF) && _CALL_ELF == 2 54 u32 *insn = func; 55 56 /* 57 * A PPC64 ABIv2 function may have a local and a global entry 58 * point. We need to use the local entry point when patching 59 * functions, so identify and step over the global entry point 60 * sequence. 61 * 62 * The global entry point sequence is always of the form: 63 * 64 * addis r2,r12,XXXX 65 * addi r2,r2,XXXX 66 * 67 * A linker optimisation may convert the addis to lis: 68 * 69 * lis r2,XXXX 70 * addi r2,r2,XXXX 71 */ 72 if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) || 73 ((*insn & OP_RT_RA_MASK) == LIS_R2)) && 74 ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2)) 75 return (unsigned long)(insn + 2); 76 else 77 return (unsigned long)func; 78 #else 79 /* 80 * On PPC64 ABIv1 the function pointer actually points to the 81 * function's descriptor. The first entry in the descriptor is the 82 * address of the function text. 83 */ 84 return ((func_descr_t *)func)->entry; 85 #endif 86 #else 87 return (unsigned long)func; 88 #endif 89 } 90 91 static inline unsigned long ppc_global_function_entry(void *func) 92 { 93 #if defined(CONFIG_PPC64) && defined(_CALL_ELF) && _CALL_ELF == 2 94 /* PPC64 ABIv2 the global entry point is at the address */ 95 return (unsigned long)func; 96 #else 97 /* All other cases there is no change vs ppc_function_entry() */ 98 return ppc_function_entry(func); 99 #endif 100 } 101 102 #ifdef CONFIG_PPC64 103 /* 104 * Some instruction encodings commonly used in dynamic ftracing 105 * and function live patching. 106 */ 107 108 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */ 109 #if defined(_CALL_ELF) && _CALL_ELF == 2 110 #define R2_STACK_OFFSET 24 111 #else 112 #define R2_STACK_OFFSET 40 113 #endif 114 115 #define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \ 116 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET) 117 118 /* usually preceded by a mflr r0 */ 119 #define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \ 120 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF) 121 #endif /* CONFIG_PPC64 */ 122 123 #endif /* _ASM_POWERPC_CODE_PATCHING_H */ 124