aha/include/asm-powerpc/code-patching.h
Kumar Gala 2d1b202762 powerpc: Fixup lwsync at runtime
To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync
at runtime.  On e500v1/v2 lwsync causes an illop so we need to patch up
the code.  We default to 'sync' since that is always safe and if the cpu
is capable we will replace 'sync' with 'lwsync'.

We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is
needed.  This flag could be moved elsewhere since we dont really use it
for the normal CPU_FTR purpose.

Finally we only store the relative offset in the fixup section to keep it
as small as possible rather than using a full fixup_entry.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-03 16:58:10 +10:00

54 lines
1.7 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>
#define PPC_NOP_INSTR 0x60000000
#define PPC_LWSYNC_INSTR 0x7c2004ac
/* 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);
unsigned int create_cond_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);
int instr_is_relative_branch(unsigned int instr);
int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr);
unsigned long branch_target(const unsigned int *instr);
unsigned int translate_branch(const unsigned int *dest,
const unsigned int *src);
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 */