From 617d2fbc45233bed182accd3507d0df4d213492c Mon Sep 17 00:00:00 2001 From: Zi Shen Lim Date: Wed, 27 Aug 2014 05:15:17 +0100 Subject: arm64: introduce aarch64_insn_gen_comp_branch_imm() Introduce function to generate compare & branch (immediate) instructions. Signed-off-by: Zi Shen Lim Acked-by: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/insn.c | 88 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 83 insertions(+), 5 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 92f36835486b..d9f7827c5058 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -2,6 +2,8 @@ * Copyright (C) 2013 Huawei Ltd. * Author: Jiang Liu * + * Copyright (C) 2014 Zi Shen Lim + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. @@ -23,6 +25,8 @@ #include #include +#define AARCH64_INSN_SF_BIT BIT(31) + static int aarch64_insn_encoding_class[] = { AARCH64_INSN_CLS_UNKNOWN, AARCH64_INSN_CLS_UNKNOWN, @@ -264,10 +268,36 @@ u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, return insn; } -u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, - enum aarch64_insn_branch_type type) +static u32 aarch64_insn_encode_register(enum aarch64_insn_register_type type, + u32 insn, + enum aarch64_insn_register reg) +{ + int shift; + + if (reg < AARCH64_INSN_REG_0 || reg > AARCH64_INSN_REG_SP) { + pr_err("%s: unknown register encoding %d\n", __func__, reg); + return 0; + } + + switch (type) { + case AARCH64_INSN_REGTYPE_RT: + shift = 0; + break; + default: + pr_err("%s: unknown register type encoding %d\n", __func__, + type); + return 0; + } + + insn &= ~(GENMASK(4, 0) << shift); + insn |= reg << shift; + + return insn; +} + +static inline long branch_imm_common(unsigned long pc, unsigned long addr, + long range) { - u32 insn; long offset; /* @@ -276,13 +306,24 @@ u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, */ BUG_ON((pc & 0x3) || (addr & 0x3)); + offset = ((long)addr - (long)pc); + BUG_ON(offset < -range || offset >= range); + + return offset; +} + +u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, + enum aarch64_insn_branch_type type) +{ + u32 insn; + long offset; + /* * B/BL support [-128M, 128M) offset * ARM64 virtual address arrangement guarantees all kernel and module * texts are within +/-128M. */ - offset = ((long)addr - (long)pc); - BUG_ON(offset < -SZ_128M || offset >= SZ_128M); + offset = branch_imm_common(pc, addr, SZ_128M); if (type == AARCH64_INSN_BRANCH_LINK) insn = aarch64_insn_get_bl_value(); @@ -293,6 +334,43 @@ u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, offset >> 2); } +u32 aarch64_insn_gen_comp_branch_imm(unsigned long pc, unsigned long addr, + enum aarch64_insn_register reg, + enum aarch64_insn_variant variant, + enum aarch64_insn_branch_type type) +{ + u32 insn; + long offset; + + offset = branch_imm_common(pc, addr, SZ_1M); + + switch (type) { + case AARCH64_INSN_BRANCH_COMP_ZERO: + insn = aarch64_insn_get_cbz_value(); + break; + case AARCH64_INSN_BRANCH_COMP_NONZERO: + insn = aarch64_insn_get_cbnz_value(); + break; + default: + BUG_ON(1); + } + + switch (variant) { + case AARCH64_INSN_VARIANT_32BIT: + break; + case AARCH64_INSN_VARIANT_64BIT: + insn |= AARCH64_INSN_SF_BIT; + break; + default: + BUG_ON(1); + } + + insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg); + + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn, + offset >> 2); +} + u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_op op) { return aarch64_insn_get_hint_value() | op; -- cgit v1.2.3-59-g8ed1b