[linux-2.6-block.git] / arch / powerpc / include / asm / code-patching.h

#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>
#include <asm/ppc-opcode.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);
unsigned int create_cond_branch(const unsigned int *addr,
				unsigned long target, int flags);
int patch_branch(unsigned int *addr, unsigned long target, int flags);
int 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);
#ifdef CONFIG_PPC_BOOK3E_64
void __patch_exception(int exc, unsigned long addr);
#define patch_exception(exc, name) do { \
	extern unsigned int name; \
	__patch_exception((exc), (unsigned long)&name); \
} while (0)
#endif

#define OP_RT_RA_MASK	0xffff0000UL
#define LIS_R2		0x3c020000UL
#define ADDIS_R2_R12	0x3c4c0000UL
#define ADDI_R2_R2	0x38420000UL

static inline unsigned long ppc_function_entry(void *func)
{
#ifdef PPC64_ELF_ABI_v2
	u32 *insn = func;

	/*
	 * A PPC64 ABIv2 function may have a local and a global entry
	 * point. We need to use the local entry point when patching
	 * functions, so identify and step over the global entry point
	 * sequence.
	 *
	 * The global entry point sequence is always of the form:
	 *
	 * addis r2,r12,XXXX
	 * addi  r2,r2,XXXX
	 *
	 * A linker optimisation may convert the addis to lis:
	 *
	 * lis   r2,XXXX
	 * addi  r2,r2,XXXX
	 */
	if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) ||
	     ((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
	    ((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
		return (unsigned long)(insn + 2);
	else
		return (unsigned long)func;
#elif defined(PPC64_ELF_ABI_v1)
	/*
	 * On PPC64 ABIv1 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
}

static inline unsigned long ppc_global_function_entry(void *func)
{
#ifdef PPC64_ELF_ABI_v2
	/* PPC64 ABIv2 the global entry point is at the address */
	return (unsigned long)func;
#else
	/* All other cases there is no change vs ppc_function_entry() */
	return ppc_function_entry(func);
#endif
}

#ifdef CONFIG_PPC64
/*
 * Some instruction encodings commonly used in dynamic ftracing
 * and function live patching.
 */

/* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
#ifdef PPC64_ELF_ABI_v2
#define R2_STACK_OFFSET         24
#else
#define R2_STACK_OFFSET         40
#endif

#define PPC_INST_LD_TOC		(PPC_INST_LD  | ___PPC_RT(__REG_R2) | \
				 ___PPC_RA(__REG_R1) | R2_STACK_OFFSET)

/* usually preceded by a mflr r0 */
#define PPC_INST_STD_LR		(PPC_INST_STD | ___PPC_RS(__REG_R0) | \
				 ___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
#endif /* CONFIG_PPC64 */

#endif /* _ASM_POWERPC_CODE_PATCHING_H */
Commit	Line	Data
aaddd3ea ME	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
07630a37	13	#include <asm/types.h>
16c57b36	14	#include <asm/ppc-opcode.h>
b7bcda63	15
aaddd3ea ME	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
e7a57273 ME	25	unsigned int create_branch(const unsigned int *addr,
e7a57273 ME	26	unsigned long target, int flags);
411781a2 ME	27	unsigned int create_cond_branch(const unsigned int *addr,
411781a2 ME	28	unsigned long target, int flags);
b6e37968 SR	29	int patch_branch(unsigned int *addr, unsigned long target, int flags);
b6e37968 SR	30	int patch_instruction(unsigned int *addr, unsigned int instr);
aaddd3ea	31
411781a2 ME	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);
1e8341ae KH	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
411781a2	44
c71b7eff AB	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
07630a37 ME	50	static inline unsigned long ppc_function_entry(void *func)
07630a37 ME	51	{
f55d9665	52	#ifdef PPC64_ELF_ABI_v2
c71b7eff AB	53	u32 *insn = func;
	54
	55	/*
	56	* A PPC64 ABIv2 function may have a local and a global entry
	57	* point. We need to use the local entry point when patching
	58	* functions, so identify and step over the global entry point
	59	* sequence.
	60	*
	61	* The global entry point sequence is always of the form:
	62	*
	63	* addis r2,r12,XXXX
	64	* addi r2,r2,XXXX
	65	*
	66	* A linker optimisation may convert the addis to lis:
	67	*
	68	* lis r2,XXXX
	69	* addi r2,r2,XXXX
	70	*/
	71	if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) \|\|
	72	((*insn & OP_RT_RA_MASK) == LIS_R2)) &&
	73	((*(insn+1) & OP_RT_RA_MASK) == ADDI_R2_R2))
	74	return (unsigned long)(insn + 2);
	75	else
	76	return (unsigned long)func;
f55d9665	77	#elif defined(PPC64_ELF_ABI_v1)
07630a37	78	/*
c71b7eff AB	79	* On PPC64 ABIv1 the function pointer actually points to the
	80	* function's descriptor. The first entry in the descriptor is the
	81	* address of the function text.
07630a37 ME	82	*/
	83	return ((func_descr_t *)func)->entry;
	84	#else
	85	return (unsigned long)func;
	86	#endif
	87	}
	88
d997c00c ME	89	static inline unsigned long ppc_global_function_entry(void *func)
d997c00c ME	90	{
f55d9665	91	#ifdef PPC64_ELF_ABI_v2
d997c00c ME	92	/* PPC64 ABIv2 the global entry point is at the address */
	93	return (unsigned long)func;
	94	#else
	95	/* All other cases there is no change vs ppc_function_entry() */
	96	return ppc_function_entry(func);
	97	#endif
	98	}
	99
15308664 TD	100	#ifdef CONFIG_PPC64
	101	/*
	102	* Some instruction encodings commonly used in dynamic ftracing
	103	* and function live patching.
	104	*/
	105
	106	/* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
f55d9665	107	#ifdef PPC64_ELF_ABI_v2
15308664 TD	108	#define R2_STACK_OFFSET 24
	109	#else
	110	#define R2_STACK_OFFSET 40
	111	#endif
	112
	113	#define PPC_INST_LD_TOC (PPC_INST_LD \| ___PPC_RT(__REG_R2) \| \
	114	___PPC_RA(__REG_R1) \| R2_STACK_OFFSET)
	115
	116	/* usually preceded by a mflr r0 */
	117	#define PPC_INST_STD_LR (PPC_INST_STD \| ___PPC_RS(__REG_R0) \| \
	118	___PPC_RA(__REG_R1) \| PPC_LR_STKOFF)
	119	#endif /* CONFIG_PPC64 */
	120
aaddd3ea	121	#endif /* _ASM_POWERPC_CODE_PATCHING_H */