diff options
Diffstat (limited to 'arch/powerpc/include/asm/code-patching.h')
| -rw-r--r-- | arch/powerpc/include/asm/code-patching.h | 67 |
1 files changed, 55 insertions, 12 deletions
diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index 409483b2d0ce..1c6316ec4b74 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -22,10 +22,55 @@ #define BRANCH_SET_LINK 0x1 #define BRANCH_ABSOLUTE 0x2 -bool is_offset_in_branch_range(long offset); -bool is_offset_in_cond_branch_range(long offset); -int create_branch(ppc_inst_t *instr, const u32 *addr, - unsigned long target, int flags); +DECLARE_STATIC_KEY_FALSE(init_mem_is_free); + +/* + * Powerpc branch instruction is : + * + * 0 6 30 31 + * +---------+----------------+---+---+ + * | opcode | LI |AA |LK | + * +---------+----------------+---+---+ + * Where AA = 0 and LK = 0 + * + * LI is a signed 24 bits integer. The real branch offset is computed + * by: imm32 = SignExtend(LI:'0b00', 32); + * + * So the maximum forward branch should be: + * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc + * The maximum backward branch should be: + * (0xff800000 << 2) = 0xfe000000 = -0x2000000 + */ +static inline bool is_offset_in_branch_range(long offset) +{ + return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); +} + +static inline bool is_offset_in_cond_branch_range(long offset) +{ + return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); +} + +static inline int create_branch(ppc_inst_t *instr, const u32 *addr, + unsigned long target, int flags) +{ + long offset; + + *instr = ppc_inst(0); + offset = target; + if (! (flags & BRANCH_ABSOLUTE)) + offset = offset - (unsigned long)addr; + + /* Check we can represent the target in the instruction format */ + if (!is_offset_in_branch_range(offset)) + return 1; + + /* Mask out the flags and target, so they don't step on each other. */ + *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC)); + + return 0; +} + int create_cond_branch(ppc_inst_t *instr, const u32 *addr, unsigned long target, int flags); int patch_branch(u32 *addr, unsigned long target, int flags); @@ -87,7 +132,7 @@ bool is_conditional_branch(ppc_inst_t instr); static inline unsigned long ppc_function_entry(void *func) { -#ifdef PPC64_ELF_ABI_v2 +#ifdef CONFIG_PPC64_ELF_ABI_V2 u32 *insn = func; /* @@ -112,7 +157,7 @@ static inline unsigned long ppc_function_entry(void *func) return (unsigned long)(insn + 2); else return (unsigned long)func; -#elif defined(PPC64_ELF_ABI_v1) +#elif defined(CONFIG_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 @@ -126,7 +171,7 @@ static inline unsigned long ppc_function_entry(void *func) static inline unsigned long ppc_global_function_entry(void *func) { -#ifdef PPC64_ELF_ABI_v2 +#ifdef CONFIG_PPC64_ELF_ABI_V2 /* PPC64 ABIv2 the global entry point is at the address */ return (unsigned long)func; #else @@ -143,7 +188,7 @@ static inline unsigned long ppc_global_function_entry(void *func) static inline unsigned long ppc_kallsyms_lookup_name(const char *name) { unsigned long addr; -#ifdef PPC64_ELF_ABI_v1 +#ifdef CONFIG_PPC64_ELF_ABI_V1 /* check for dot variant */ char dot_name[1 + KSYM_NAME_LEN]; bool dot_appended = false; @@ -164,7 +209,7 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *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) +#elif defined(CONFIG_PPC64_ELF_ABI_V2) addr = kallsyms_lookup_name(name); if (addr) addr = ppc_function_entry((void *)addr); @@ -174,14 +219,13 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *name) 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 +#ifdef CONFIG_PPC64_ELF_ABI_V2 #define R2_STACK_OFFSET 24 #else #define R2_STACK_OFFSET 40 @@ -191,6 +235,5 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *name) /* usually preceded by a mflr r0 */ #define PPC_INST_STD_LR PPC_RAW_STD(_R0, _R1, PPC_LR_STKOFF) -#endif /* CONFIG_PPC64 */ #endif /* _ASM_POWERPC_CODE_PATCHING_H */ |