[PATCH RFCv3 01/14] arm64: introduce aarch64_insn_gen_comp_branch_imm()
Zi Shen Lim
zlim.lnx at gmail.com
Mon Jul 14 23:24:59 PDT 2014
Introduce function to generate compare & branch (immediate)
instructions.
Signed-off-by: Zi Shen Lim <zlim.lnx at gmail.com>
---
arch/arm64/include/asm/insn.h | 57 ++++++++++++++++++++++++++++
arch/arm64/kernel/insn.c | 86 ++++++++++++++++++++++++++++++++++++++++---
2 files changed, 138 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index dc1f73b..a98c495 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -2,6 +2,8 @@
* Copyright (C) 2013 Huawei Ltd.
* Author: Jiang Liu <liuj97 at gmail.com>
*
+ * Copyright (C) 2014 Zi Shen Lim <zlim.lnx at gmail.com>
+ *
* 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.
@@ -67,9 +69,58 @@ enum aarch64_insn_imm_type {
AARCH64_INSN_IMM_MAX
};
+enum aarch64_insn_register_type {
+ AARCH64_INSN_REGTYPE_RT,
+};
+
+enum aarch64_insn_register {
+ AARCH64_INSN_REG_0 = 0,
+ AARCH64_INSN_REG_1 = 1,
+ AARCH64_INSN_REG_2 = 2,
+ AARCH64_INSN_REG_3 = 3,
+ AARCH64_INSN_REG_4 = 4,
+ AARCH64_INSN_REG_5 = 5,
+ AARCH64_INSN_REG_6 = 6,
+ AARCH64_INSN_REG_7 = 7,
+ AARCH64_INSN_REG_8 = 8,
+ AARCH64_INSN_REG_9 = 9,
+ AARCH64_INSN_REG_10 = 10,
+ AARCH64_INSN_REG_11 = 11,
+ AARCH64_INSN_REG_12 = 12,
+ AARCH64_INSN_REG_13 = 13,
+ AARCH64_INSN_REG_14 = 14,
+ AARCH64_INSN_REG_15 = 15,
+ AARCH64_INSN_REG_16 = 16,
+ AARCH64_INSN_REG_17 = 17,
+ AARCH64_INSN_REG_18 = 18,
+ AARCH64_INSN_REG_19 = 19,
+ AARCH64_INSN_REG_20 = 20,
+ AARCH64_INSN_REG_21 = 21,
+ AARCH64_INSN_REG_22 = 22,
+ AARCH64_INSN_REG_23 = 23,
+ AARCH64_INSN_REG_24 = 24,
+ AARCH64_INSN_REG_25 = 25,
+ AARCH64_INSN_REG_26 = 26,
+ AARCH64_INSN_REG_27 = 27,
+ AARCH64_INSN_REG_28 = 28,
+ AARCH64_INSN_REG_29 = 29,
+ AARCH64_INSN_REG_FP = 29, /* Frame pointer */
+ AARCH64_INSN_REG_30 = 30,
+ AARCH64_INSN_REG_LR = 30, /* Link register */
+ AARCH64_INSN_REG_ZR = 31, /* Zero: as source register */
+ AARCH64_INSN_REG_SP = 31 /* Stack pointer: as load/store base reg */
+};
+
+enum aarch64_insn_variant {
+ AARCH64_INSN_VARIANT_32BIT,
+ AARCH64_INSN_VARIANT_64BIT
+};
+
enum aarch64_insn_branch_type {
AARCH64_INSN_BRANCH_NOLINK,
AARCH64_INSN_BRANCH_LINK,
+ AARCH64_INSN_BRANCH_COMP_ZERO,
+ AARCH64_INSN_BRANCH_COMP_NONZERO,
};
#define __AARCH64_INSN_FUNCS(abbr, mask, val) \
@@ -80,6 +131,8 @@ static __always_inline u32 aarch64_insn_get_##abbr##_value(void) \
__AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000)
__AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000)
+__AARCH64_INSN_FUNCS(cbz, 0xFE000000, 0x34000000)
+__AARCH64_INSN_FUNCS(cbnz, 0xFE000000, 0x35000000)
__AARCH64_INSN_FUNCS(svc, 0xFFE0001F, 0xD4000001)
__AARCH64_INSN_FUNCS(hvc, 0xFFE0001F, 0xD4000002)
__AARCH64_INSN_FUNCS(smc, 0xFFE0001F, 0xD4000003)
@@ -97,6 +150,10 @@ u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
u32 insn, u64 imm);
u32 aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr,
enum aarch64_insn_branch_type type);
+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 aarch64_insn_gen_hint(enum aarch64_insn_hint_op op);
u32 aarch64_insn_gen_nop(void);
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 92f3683..d01bb4e 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 <liuj97 at gmail.com>
*
+ * Copyright (C) 2014 Zi Shen Lim <zlim.lnx at gmail.com>
+ *
* 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.
@@ -264,10 +266,36 @@ 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 +304,24 @@ 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 +332,43 @@ 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 |= BIT(31);
+ 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;
--
1.9.1
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