170 lines
5 KiB
C
Executable file
170 lines
5 KiB
C
Executable file
#ifndef _ASM_POWERPC_CODE_PATCHING_H
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#define _ASM_POWERPC_CODE_PATCHING_H
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/*
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* Copyright 2008, Michael Ellerman, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <asm/types.h>
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#include <asm/ppc-opcode.h>
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#include <linux/string.h>
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#include <linux/kallsyms.h>
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#include <asm/asm-compat.h>
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/* Flags for create_branch:
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* "b" == create_branch(addr, target, 0);
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* "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
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* "bl" == create_branch(addr, target, BRANCH_SET_LINK);
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* "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
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*/
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#define BRANCH_SET_LINK 0x1
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#define BRANCH_ABSOLUTE 0x2
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bool is_offset_in_branch_range(long offset);
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unsigned int create_branch(const unsigned int *addr,
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unsigned long target, int flags);
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unsigned int create_cond_branch(const unsigned int *addr,
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unsigned long target, int flags);
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int patch_branch(unsigned int *addr, unsigned long target, int flags);
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int patch_instruction(unsigned int *addr, unsigned int instr);
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int raw_patch_instruction(unsigned int *addr, unsigned int instr);
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int patch_instruction_site(s32 *addr, unsigned int instr);
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int patch_branch_site(s32 *site, unsigned long target, int flags);
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int instr_is_relative_branch(unsigned int instr);
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int instr_is_relative_link_branch(unsigned int instr);
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int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
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unsigned long branch_target(const unsigned int *instr);
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unsigned int translate_branch(const unsigned int *dest,
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const unsigned int *src);
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extern bool is_conditional_branch(unsigned int instr);
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#ifdef CONFIG_PPC_BOOK3E_64
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void __patch_exception(int exc, unsigned long addr);
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#define patch_exception(exc, name) do { \
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extern unsigned int name; \
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__patch_exception((exc), (unsigned long)&name); \
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} while (0)
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#endif
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#define OP_RT_RA_MASK 0xffff0000UL
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#define LIS_R2 0x3c400000UL
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#define ADDIS_R2_R12 0x3c4c0000UL
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#define ADDI_R2_R2 0x38420000UL
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static inline unsigned long ppc_function_entry(void *func)
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{
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#ifdef PPC64_ELF_ABI_v2
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u32 *insn = func;
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/*
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* A PPC64 ABIv2 function may have a local and a global entry
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* point. We need to use the local entry point when patching
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* functions, so identify and step over the global entry point
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* sequence.
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*
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* The global entry point sequence is always of the form:
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*
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* addis r2,r12,XXXX
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* addi r2,r2,XXXX
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*
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* A linker optimisation may convert the addis to lis:
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*
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* lis r2,XXXX
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* addi r2,r2,XXXX
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*/
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if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
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((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
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((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
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return (unsigned long)(insn + 2);
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else
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return (unsigned long)func;
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#elif defined(PPC64_ELF_ABI_v1)
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/*
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* On PPC64 ABIv1 the function pointer actually points to the
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* function's descriptor. The first entry in the descriptor is the
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* address of the function text.
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*/
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return ((func_descr_t *)func)->entry;
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#else
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return (unsigned long)func;
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#endif
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}
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static inline unsigned long ppc_global_function_entry(void *func)
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{
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#ifdef PPC64_ELF_ABI_v2
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/* PPC64 ABIv2 the global entry point is at the address */
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return (unsigned long)func;
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#else
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/* All other cases there is no change vs ppc_function_entry() */
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return ppc_function_entry(func);
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#endif
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}
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/*
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* Wrapper around kallsyms_lookup() to return function entry address:
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* - For ABIv1, we lookup the dot variant.
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* - For ABIv2, we return the local entry point.
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*/
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static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
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{
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unsigned long addr;
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#ifdef PPC64_ELF_ABI_v1
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/* check for dot variant */
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char dot_name[1 + KSYM_NAME_LEN];
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bool dot_appended = false;
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if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)
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return 0;
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if (name[0] != '.') {
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dot_name[0] = '.';
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dot_name[1] = '\0';
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strlcat(dot_name, name, sizeof(dot_name));
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dot_appended = true;
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} else {
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dot_name[0] = '\0';
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strlcat(dot_name, name, sizeof(dot_name));
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}
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addr = kallsyms_lookup_name(dot_name);
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if (!addr && dot_appended)
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/* Let's try the original non-dot symbol lookup */
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addr = kallsyms_lookup_name(name);
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#elif defined(PPC64_ELF_ABI_v2)
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addr = kallsyms_lookup_name(name);
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if (addr)
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addr = ppc_function_entry((void *)addr);
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#else
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addr = kallsyms_lookup_name(name);
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#endif
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return addr;
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}
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#ifdef CONFIG_PPC64
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/*
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* Some instruction encodings commonly used in dynamic ftracing
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* and function live patching.
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*/
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/* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
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#ifdef PPC64_ELF_ABI_v2
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#define R2_STACK_OFFSET 24
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#else
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#define R2_STACK_OFFSET 40
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#endif
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#define PPC_INST_LD_TOC (PPC_INST_LD | ___PPC_RT(__REG_R2) | \
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___PPC_RA(__REG_R1) | R2_STACK_OFFSET)
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/* usually preceded by a mflr r0 */
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#define PPC_INST_STD_LR (PPC_INST_STD | ___PPC_RS(__REG_R0) | \
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___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
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#endif /* CONFIG_PPC64 */
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#endif /* _ASM_POWERPC_CODE_PATCHING_H */
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