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ABIv2 has the concept of a global and local entry point to a function. In most cases we are interested in the local entry point, and so that is what ppc_function_entry() returns. However we have a case in the ftrace code where we want the global entry point, and there may be other places we need it too. Rather than special casing each, add an accessor. For ABIv1 and 32-bit there is only a single entry point, so we return that. That means it's safe for the caller to use this without also checking the ABI version. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
#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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/* 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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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 instr_is_relative_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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#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 0x3c020000UL
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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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#if defined(CONFIG_PPC64)
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#if defined(_CALL_ELF) && _CALL_ELF == 2
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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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#else
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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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#endif
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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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#if defined(CONFIG_PPC64) && defined(_CALL_ELF) && _CALL_ELF == 2
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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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#endif /* _ASM_POWERPC_CODE_PATCHING_H */
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