#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>#include <linux/string.h>#include <linux/kallsyms.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 bool is_offset_in_branch_range(long offset);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);extern bool is_conditional_branch(unsigned int instr);#ifdef CONFIG_PPC_BOOK3E_64void __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.	 *	 * However, we may also receive pointer to an assembly symbol. To	 * detect that, we first check if the function pointer we receive	 * already points to kernel/module text and we only dereference it	 * if it doesn't.	 */	if (kernel_text_address((unsigned long)func))		return (unsigned long)func;	else		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} /* * Wrapper around kallsyms_lookup() to return function entry address: * - For ABIv1, we lookup the dot variant. * - For ABIv2, we return the local entry point. */static inline unsigned long ppc_kallsyms_lookup_name(const char *name){	unsigned long addr;#ifdef PPC64_ELF_ABI_v1	/* check for dot variant */	char dot_name[1 + KSYM_NAME_LEN];	bool dot_appended = false; 	if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)		return 0; 	if (name[0] != '.') {		dot_name[0] = '.';		dot_name[1] = '\0';		strlcat(dot_name, name, sizeof(dot_name));		dot_appended = true;	} else {		dot_name[0] = '\0';		strlcat(dot_name, name, sizeof(dot_name));	}	addr = kallsyms_lookup_name(dot_name);	if (!addr && dot_appended)		/* Let's try the original non-dot symbol lookup	*/		addr = kallsyms_lookup_name(name);#elif defined(PPC64_ELF_ABI_v2)	addr = kallsyms_lookup_name(name);	if (addr)		addr = ppc_function_entry((void *)addr);#else	addr = kallsyms_lookup_name(name);#endif	return addr;} #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 */