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arm64: introduce aarch64_insn_gen_comp_branch_imm()

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Introduce function to generate compare & branch (immediate)
instructions.

Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Zi Shen Lim
2014-08-27 05:15:17 +01:00
committed by Will Deacon
parent a4ceab1adb
commit 617d2fbc45
2 changed files with 140 additions and 5 deletions
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88
arch/arm64/kernel/insn.c
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@@ -2,6 +2,8 @@
* Copyright (C) 2013 Huawei Ltd.
* Author: Jiang Liu <liuj97@gmail.com>
*
* Copyright (C) 2014 Zi Shen Lim <zlim.lnx@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.
@@ -23,6 +25,8 @@
#include <asm/cacheflush.h>
#include <asm/insn.h>
#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;