linux/include/asm-powerpc/code-patching.h
Michael Ellerman 07630a37be powerpc: Add ppc_function_entry() which gets the entry point for a function
Because function pointers point to different things on 32-bit vs 64-bit,
add a macro that deals with dereferencing the OPD on 64-bit.  The soon to
be merged ftrace wants this, as well as other code I am working on.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01 11:28:20 +10:00

44 lines
1.3 KiB
C

#ifndef _ASM_POWERPC_CODE_PATCHING_H
#define _ASM_POWERPC_CODE_PATCHING_H
/*
* Copyright 2008, Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/types.h>
/* Flags for create_branch:
* "b" == create_branch(addr, target, 0);
* "ba" == create_branch(addr, target, BRANCH_ABSOLUTE);
* "bl" == create_branch(addr, target, BRANCH_SET_LINK);
* "bla" == create_branch(addr, target, BRANCH_ABSOLUTE | BRANCH_SET_LINK);
*/
#define BRANCH_SET_LINK 0x1
#define BRANCH_ABSOLUTE 0x2
unsigned int create_branch(const unsigned int *addr,
unsigned long target, int flags);
void patch_branch(unsigned int *addr, unsigned long target, int flags);
void patch_instruction(unsigned int *addr, unsigned int instr);
static inline unsigned long ppc_function_entry(void *func)
{
#ifdef CONFIG_PPC64
/*
* On PPC64 the function pointer actually points to the function's
* descriptor. The first entry in the descriptor is the address
* of the function text.
*/
return ((func_descr_t *)func)->entry;
#else
return (unsigned long)func;
#endif
}
#endif /* _ASM_POWERPC_CODE_PATCHING_H */