insn.c 32.6 KB
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/*
 * Copyright (C) 2013 Huawei Ltd.
 * Author: Jiang Liu <liuj97@gmail.com>
 *
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 * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
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 *
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 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
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#include <linux/bitops.h>
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#include <linux/bug.h>
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#include <linux/compiler.h>
#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/spinlock.h>
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#include <linux/stop_machine.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#include <asm/debug-monitors.h>
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#include <asm/fixmap.h>
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#include <asm/opcodes.h>
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#include <asm/insn.h>

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#define AARCH64_INSN_SF_BIT	BIT(31)
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#define AARCH64_INSN_N_BIT	BIT(22)
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static int aarch64_insn_encoding_class[] = {
	AARCH64_INSN_CLS_UNKNOWN,
	AARCH64_INSN_CLS_UNKNOWN,
	AARCH64_INSN_CLS_UNKNOWN,
	AARCH64_INSN_CLS_UNKNOWN,
	AARCH64_INSN_CLS_LDST,
	AARCH64_INSN_CLS_DP_REG,
	AARCH64_INSN_CLS_LDST,
	AARCH64_INSN_CLS_DP_FPSIMD,
	AARCH64_INSN_CLS_DP_IMM,
	AARCH64_INSN_CLS_DP_IMM,
	AARCH64_INSN_CLS_BR_SYS,
	AARCH64_INSN_CLS_BR_SYS,
	AARCH64_INSN_CLS_LDST,
	AARCH64_INSN_CLS_DP_REG,
	AARCH64_INSN_CLS_LDST,
	AARCH64_INSN_CLS_DP_FPSIMD,
};

enum aarch64_insn_encoding_class __kprobes aarch64_get_insn_class(u32 insn)
{
	return aarch64_insn_encoding_class[(insn >> 25) & 0xf];
}

/* NOP is an alias of HINT */
bool __kprobes aarch64_insn_is_nop(u32 insn)
{
	if (!aarch64_insn_is_hint(insn))
		return false;

	switch (insn & 0xFE0) {
	case AARCH64_INSN_HINT_YIELD:
	case AARCH64_INSN_HINT_WFE:
	case AARCH64_INSN_HINT_WFI:
	case AARCH64_INSN_HINT_SEV:
	case AARCH64_INSN_HINT_SEVL:
		return false;
	default:
		return true;
	}
}

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bool aarch64_insn_is_branch_imm(u32 insn)
{
	return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) ||
		aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) ||
		aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
		aarch64_insn_is_bcond(insn));
}

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static DEFINE_RAW_SPINLOCK(patch_lock);
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static void __kprobes *patch_map(void *addr, int fixmap)
{
	unsigned long uintaddr = (uintptr_t) addr;
	bool module = !core_kernel_text(uintaddr);
	struct page *page;

	if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
		page = vmalloc_to_page(addr);
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	else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
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		page = pfn_to_page(PHYS_PFN(__pa(addr)));
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	else
		return addr;
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	BUG_ON(!page);
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	return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
			(uintaddr & ~PAGE_MASK));
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}

static void __kprobes patch_unmap(int fixmap)
{
	clear_fixmap(fixmap);
}
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/*
 * In ARMv8-A, A64 instructions have a fixed length of 32 bits and are always
 * little-endian.
 */
int __kprobes aarch64_insn_read(void *addr, u32 *insnp)
{
	int ret;
	u32 val;

	ret = probe_kernel_read(&val, addr, AARCH64_INSN_SIZE);
	if (!ret)
		*insnp = le32_to_cpu(val);

	return ret;
}

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static int __kprobes __aarch64_insn_write(void *addr, u32 insn)
{
	void *waddr = addr;
	unsigned long flags = 0;
	int ret;

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	raw_spin_lock_irqsave(&patch_lock, flags);
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	waddr = patch_map(addr, FIX_TEXT_POKE0);

	ret = probe_kernel_write(waddr, &insn, AARCH64_INSN_SIZE);

	patch_unmap(FIX_TEXT_POKE0);
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	raw_spin_unlock_irqrestore(&patch_lock, flags);
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	return ret;
}

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int __kprobes aarch64_insn_write(void *addr, u32 insn)
{
	insn = cpu_to_le32(insn);
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	return __aarch64_insn_write(addr, insn);
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}

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static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn)
{
	if (aarch64_get_insn_class(insn) != AARCH64_INSN_CLS_BR_SYS)
		return false;

	return	aarch64_insn_is_b(insn) ||
		aarch64_insn_is_bl(insn) ||
		aarch64_insn_is_svc(insn) ||
		aarch64_insn_is_hvc(insn) ||
		aarch64_insn_is_smc(insn) ||
		aarch64_insn_is_brk(insn) ||
		aarch64_insn_is_nop(insn);
}

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bool __kprobes aarch64_insn_uses_literal(u32 insn)
{
	/* ldr/ldrsw (literal), prfm */

	return aarch64_insn_is_ldr_lit(insn) ||
		aarch64_insn_is_ldrsw_lit(insn) ||
		aarch64_insn_is_adr_adrp(insn) ||
		aarch64_insn_is_prfm_lit(insn);
}

bool __kprobes aarch64_insn_is_branch(u32 insn)
{
	/* b, bl, cb*, tb*, b.cond, br, blr */

	return aarch64_insn_is_b(insn) ||
		aarch64_insn_is_bl(insn) ||
		aarch64_insn_is_cbz(insn) ||
		aarch64_insn_is_cbnz(insn) ||
		aarch64_insn_is_tbz(insn) ||
		aarch64_insn_is_tbnz(insn) ||
		aarch64_insn_is_ret(insn) ||
		aarch64_insn_is_br(insn) ||
		aarch64_insn_is_blr(insn) ||
		aarch64_insn_is_bcond(insn);
}

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/*
 * ARM Architecture Reference Manual for ARMv8 Profile-A, Issue A.a
 * Section B2.6.5 "Concurrent modification and execution of instructions":
 * Concurrent modification and execution of instructions can lead to the
 * resulting instruction performing any behavior that can be achieved by
 * executing any sequence of instructions that can be executed from the
 * same Exception level, except where the instruction before modification
 * and the instruction after modification is a B, BL, NOP, BKPT, SVC, HVC,
 * or SMC instruction.
 */
bool __kprobes aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn)
{
	return __aarch64_insn_hotpatch_safe(old_insn) &&
	       __aarch64_insn_hotpatch_safe(new_insn);
}
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int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn)
{
	u32 *tp = addr;
	int ret;

	/* A64 instructions must be word aligned */
	if ((uintptr_t)tp & 0x3)
		return -EINVAL;

	ret = aarch64_insn_write(tp, insn);
	if (ret == 0)
		flush_icache_range((uintptr_t)tp,
				   (uintptr_t)tp + AARCH64_INSN_SIZE);

	return ret;
}

struct aarch64_insn_patch {
	void		**text_addrs;
	u32		*new_insns;
	int		insn_cnt;
	atomic_t	cpu_count;
};

static int __kprobes aarch64_insn_patch_text_cb(void *arg)
{
	int i, ret = 0;
	struct aarch64_insn_patch *pp = arg;

	/* The first CPU becomes master */
	if (atomic_inc_return(&pp->cpu_count) == 1) {
		for (i = 0; ret == 0 && i < pp->insn_cnt; i++)
			ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i],
							     pp->new_insns[i]);
		/*
		 * aarch64_insn_patch_text_nosync() calls flush_icache_range(),
		 * which ends with "dsb; isb" pair guaranteeing global
		 * visibility.
		 */
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		/* Notify other processors with an additional increment. */
		atomic_inc(&pp->cpu_count);
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	} else {
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		while (atomic_read(&pp->cpu_count) <= num_online_cpus())
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			cpu_relax();
		isb();
	}

	return ret;
}

int __kprobes aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt)
{
	struct aarch64_insn_patch patch = {
		.text_addrs = addrs,
		.new_insns = insns,
		.insn_cnt = cnt,
		.cpu_count = ATOMIC_INIT(0),
	};

	if (cnt <= 0)
		return -EINVAL;

	return stop_machine(aarch64_insn_patch_text_cb, &patch,
			    cpu_online_mask);
}

int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
{
	int ret;
	u32 insn;

	/* Unsafe to patch multiple instructions without synchronizaiton */
	if (cnt == 1) {
		ret = aarch64_insn_read(addrs[0], &insn);
		if (ret)
			return ret;

		if (aarch64_insn_hotpatch_safe(insn, insns[0])) {
			/*
			 * ARMv8 architecture doesn't guarantee all CPUs see
			 * the new instruction after returning from function
			 * aarch64_insn_patch_text_nosync(). So send IPIs to
			 * all other CPUs to achieve instruction
			 * synchronization.
			 */
			ret = aarch64_insn_patch_text_nosync(addrs[0], insns[0]);
			kick_all_cpus_sync();
			return ret;
		}
	}

	return aarch64_insn_patch_text_sync(addrs, insns, cnt);
}
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static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
						u32 *maskp, int *shiftp)
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{
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	u32 mask;
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	int shift;

	switch (type) {
	case AARCH64_INSN_IMM_26:
		mask = BIT(26) - 1;
		shift = 0;
		break;
	case AARCH64_INSN_IMM_19:
		mask = BIT(19) - 1;
		shift = 5;
		break;
	case AARCH64_INSN_IMM_16:
		mask = BIT(16) - 1;
		shift = 5;
		break;
	case AARCH64_INSN_IMM_14:
		mask = BIT(14) - 1;
		shift = 5;
		break;
	case AARCH64_INSN_IMM_12:
		mask = BIT(12) - 1;
		shift = 10;
		break;
	case AARCH64_INSN_IMM_9:
		mask = BIT(9) - 1;
		shift = 12;
		break;
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	case AARCH64_INSN_IMM_7:
		mask = BIT(7) - 1;
		shift = 15;
		break;
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	case AARCH64_INSN_IMM_6:
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	case AARCH64_INSN_IMM_S:
		mask = BIT(6) - 1;
		shift = 10;
		break;
	case AARCH64_INSN_IMM_R:
		mask = BIT(6) - 1;
		shift = 16;
		break;
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	default:
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		return -EINVAL;
	}

	*maskp = mask;
	*shiftp = shift;

	return 0;
}

#define ADR_IMM_HILOSPLIT	2
#define ADR_IMM_SIZE		SZ_2M
#define ADR_IMM_LOMASK		((1 << ADR_IMM_HILOSPLIT) - 1)
#define ADR_IMM_HIMASK		((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1)
#define ADR_IMM_LOSHIFT		29
#define ADR_IMM_HISHIFT		5

u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn)
{
	u32 immlo, immhi, mask;
	int shift;

	switch (type) {
	case AARCH64_INSN_IMM_ADR:
		shift = 0;
		immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK;
		immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK;
		insn = (immhi << ADR_IMM_HILOSPLIT) | immlo;
		mask = ADR_IMM_SIZE - 1;
		break;
	default:
		if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
			pr_err("aarch64_insn_decode_immediate: unknown immediate encoding %d\n",
			       type);
			return 0;
		}
	}

	return (insn >> shift) & mask;
}

u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
				  u32 insn, u64 imm)
{
	u32 immlo, immhi, mask;
	int shift;

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	if (insn == AARCH64_BREAK_FAULT)
		return AARCH64_BREAK_FAULT;

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	switch (type) {
	case AARCH64_INSN_IMM_ADR:
		shift = 0;
		immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT;
		imm >>= ADR_IMM_HILOSPLIT;
		immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT;
		imm = immlo | immhi;
		mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) |
			(ADR_IMM_HIMASK << ADR_IMM_HISHIFT));
		break;
	default:
		if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
			pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
			       type);
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			return AARCH64_BREAK_FAULT;
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		}
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	}

	/* Update the immediate field. */
	insn &= ~(mask << shift);
	insn |= (imm & mask) << shift;

	return insn;
}
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static u32 aarch64_insn_encode_register(enum aarch64_insn_register_type type,
					u32 insn,
					enum aarch64_insn_register reg)
{
	int shift;

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	if (insn == AARCH64_BREAK_FAULT)
		return AARCH64_BREAK_FAULT;

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	if (reg < AARCH64_INSN_REG_0 || reg > AARCH64_INSN_REG_SP) {
		pr_err("%s: unknown register encoding %d\n", __func__, reg);
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		return AARCH64_BREAK_FAULT;
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	}

	switch (type) {
	case AARCH64_INSN_REGTYPE_RT:
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	case AARCH64_INSN_REGTYPE_RD:
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		shift = 0;
		break;
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	case AARCH64_INSN_REGTYPE_RN:
		shift = 5;
		break;
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	case AARCH64_INSN_REGTYPE_RT2:
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	case AARCH64_INSN_REGTYPE_RA:
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		shift = 10;
		break;
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	case AARCH64_INSN_REGTYPE_RM:
		shift = 16;
		break;
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	default:
		pr_err("%s: unknown register type encoding %d\n", __func__,
		       type);
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		return AARCH64_BREAK_FAULT;
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	}

	insn &= ~(GENMASK(4, 0) << shift);
	insn |= reg << shift;

	return insn;
}

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static u32 aarch64_insn_encode_ldst_size(enum aarch64_insn_size_type type,
					 u32 insn)
{
	u32 size;

	switch (type) {
	case AARCH64_INSN_SIZE_8:
		size = 0;
		break;
	case AARCH64_INSN_SIZE_16:
		size = 1;
		break;
	case AARCH64_INSN_SIZE_32:
		size = 2;
		break;
	case AARCH64_INSN_SIZE_64:
		size = 3;
		break;
	default:
		pr_err("%s: unknown size encoding %d\n", __func__, type);
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		return AARCH64_BREAK_FAULT;
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	}

	insn &= ~GENMASK(31, 30);
	insn |= size << 30;

	return insn;
}

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static inline long branch_imm_common(unsigned long pc, unsigned long addr,
				     long range)
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{
	long offset;

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	if ((pc & 0x3) || (addr & 0x3)) {
		pr_err("%s: A64 instructions must be word aligned\n", __func__);
		return range;
	}
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	offset = ((long)addr - (long)pc);
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	if (offset < -range || offset >= range) {
		pr_err("%s: offset out of range\n", __func__);
		return range;
	}
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	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;

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	/*
	 * B/BL support [-128M, 128M) offset
	 * ARM64 virtual address arrangement guarantees all kernel and module
	 * texts are within +/-128M.
	 */
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	offset = branch_imm_common(pc, addr, SZ_128M);
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	if (offset >= SZ_128M)
		return AARCH64_BREAK_FAULT;
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	switch (type) {
	case AARCH64_INSN_BRANCH_LINK:
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		insn = aarch64_insn_get_bl_value();
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		break;
	case AARCH64_INSN_BRANCH_NOLINK:
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		insn = aarch64_insn_get_b_value();
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		break;
	default:
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		pr_err("%s: unknown branch encoding %d\n", __func__, type);
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		return AARCH64_BREAK_FAULT;
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	}
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	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
					     offset >> 2);
}

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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);
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	if (offset >= SZ_1M)
		return AARCH64_BREAK_FAULT;
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	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:
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		pr_err("%s: unknown branch encoding %d\n", __func__, type);
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		return AARCH64_BREAK_FAULT;
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	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
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		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
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		return AARCH64_BREAK_FAULT;
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	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
					     offset >> 2);
}

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u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr,
				     enum aarch64_insn_condition cond)
{
	u32 insn;
	long offset;

	offset = branch_imm_common(pc, addr, SZ_1M);

	insn = aarch64_insn_get_bcond_value();

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	if (cond < AARCH64_INSN_COND_EQ || cond > AARCH64_INSN_COND_AL) {
		pr_err("%s: unknown condition encoding %d\n", __func__, cond);
		return AARCH64_BREAK_FAULT;
	}
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	insn |= cond;

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
					     offset >> 2);
}

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u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_op op)
{
	return aarch64_insn_get_hint_value() | op;
}

u32 __kprobes aarch64_insn_gen_nop(void)
{
	return aarch64_insn_gen_hint(AARCH64_INSN_HINT_NOP);
}
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u32 aarch64_insn_gen_branch_reg(enum aarch64_insn_register reg,
				enum aarch64_insn_branch_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_BRANCH_NOLINK:
		insn = aarch64_insn_get_br_value();
		break;
	case AARCH64_INSN_BRANCH_LINK:
		insn = aarch64_insn_get_blr_value();
		break;
	case AARCH64_INSN_BRANCH_RETURN:
		insn = aarch64_insn_get_ret_value();
		break;
	default:
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		pr_err("%s: unknown branch encoding %d\n", __func__, type);
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		return AARCH64_BREAK_FAULT;
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	}

	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, reg);
}
635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651

u32 aarch64_insn_gen_load_store_reg(enum aarch64_insn_register reg,
				    enum aarch64_insn_register base,
				    enum aarch64_insn_register offset,
				    enum aarch64_insn_size_type size,
				    enum aarch64_insn_ldst_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_LDST_LOAD_REG_OFFSET:
		insn = aarch64_insn_get_ldr_reg_value();
		break;
	case AARCH64_INSN_LDST_STORE_REG_OFFSET:
		insn = aarch64_insn_get_str_reg_value();
		break;
	default:
652
		pr_err("%s: unknown load/store encoding %d\n", __func__, type);
653
		return AARCH64_BREAK_FAULT;
654 655 656 657 658 659 660 661 662 663 664 665
	}

	insn = aarch64_insn_encode_ldst_size(size, insn);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
					    base);

	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn,
					    offset);
}
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690

u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
				     enum aarch64_insn_register reg2,
				     enum aarch64_insn_register base,
				     int offset,
				     enum aarch64_insn_variant variant,
				     enum aarch64_insn_ldst_type type)
{
	u32 insn;
	int shift;

	switch (type) {
	case AARCH64_INSN_LDST_LOAD_PAIR_PRE_INDEX:
		insn = aarch64_insn_get_ldp_pre_value();
		break;
	case AARCH64_INSN_LDST_STORE_PAIR_PRE_INDEX:
		insn = aarch64_insn_get_stp_pre_value();
		break;
	case AARCH64_INSN_LDST_LOAD_PAIR_POST_INDEX:
		insn = aarch64_insn_get_ldp_post_value();
		break;
	case AARCH64_INSN_LDST_STORE_PAIR_POST_INDEX:
		insn = aarch64_insn_get_stp_post_value();
		break;
	default:
691
		pr_err("%s: unknown load/store encoding %d\n", __func__, type);
692
		return AARCH64_BREAK_FAULT;
693 694 695 696
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
697 698 699 700 701
		if ((offset & 0x3) || (offset < -256) || (offset > 252)) {
			pr_err("%s: offset must be multiples of 4 in the range of [-256, 252] %d\n",
			       __func__, offset);
			return AARCH64_BREAK_FAULT;
		}
702 703 704
		shift = 2;
		break;
	case AARCH64_INSN_VARIANT_64BIT:
705 706 707 708 709
		if ((offset & 0x7) || (offset < -512) || (offset > 504)) {
			pr_err("%s: offset must be multiples of 8 in the range of [-512, 504] %d\n",
			       __func__, offset);
			return AARCH64_BREAK_FAULT;
		}
710 711 712 713
		shift = 3;
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
714
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
715
		return AARCH64_BREAK_FAULT;
716 717 718 719 720 721 722 723 724 725 726 727 728 729
	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
					    reg1);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT2, insn,
					    reg2);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
					    base);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_7, insn,
					     offset >> shift);
}
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751

u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst,
				 enum aarch64_insn_register src,
				 int imm, enum aarch64_insn_variant variant,
				 enum aarch64_insn_adsb_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_ADSB_ADD:
		insn = aarch64_insn_get_add_imm_value();
		break;
	case AARCH64_INSN_ADSB_SUB:
		insn = aarch64_insn_get_sub_imm_value();
		break;
	case AARCH64_INSN_ADSB_ADD_SETFLAGS:
		insn = aarch64_insn_get_adds_imm_value();
		break;
	case AARCH64_INSN_ADSB_SUB_SETFLAGS:
		insn = aarch64_insn_get_subs_imm_value();
		break;
	default:
752
		pr_err("%s: unknown add/sub encoding %d\n", __func__, type);
753
		return AARCH64_BREAK_FAULT;
754 755 756 757 758 759 760 761 762
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
763
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
764
		return AARCH64_BREAK_FAULT;
765 766
	}

767 768 769 770
	if (imm & ~(SZ_4K - 1)) {
		pr_err("%s: invalid immediate encoding %d\n", __func__, imm);
		return AARCH64_BREAK_FAULT;
	}
771 772 773 774 775 776 777

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);
}
778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798

u32 aarch64_insn_gen_bitfield(enum aarch64_insn_register dst,
			      enum aarch64_insn_register src,
			      int immr, int imms,
			      enum aarch64_insn_variant variant,
			      enum aarch64_insn_bitfield_type type)
{
	u32 insn;
	u32 mask;

	switch (type) {
	case AARCH64_INSN_BITFIELD_MOVE:
		insn = aarch64_insn_get_bfm_value();
		break;
	case AARCH64_INSN_BITFIELD_MOVE_UNSIGNED:
		insn = aarch64_insn_get_ubfm_value();
		break;
	case AARCH64_INSN_BITFIELD_MOVE_SIGNED:
		insn = aarch64_insn_get_sbfm_value();
		break;
	default:
799
		pr_err("%s: unknown bitfield encoding %d\n", __func__, type);
800
		return AARCH64_BREAK_FAULT;
801 802 803 804 805 806 807 808 809 810 811
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		mask = GENMASK(4, 0);
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT | AARCH64_INSN_N_BIT;
		mask = GENMASK(5, 0);
		break;
	default:
812
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
813
		return AARCH64_BREAK_FAULT;
814 815
	}

816 817 818 819 820 821 822 823
	if (immr & ~mask) {
		pr_err("%s: invalid immr encoding %d\n", __func__, immr);
		return AARCH64_BREAK_FAULT;
	}
	if (imms & ~mask) {
		pr_err("%s: invalid imms encoding %d\n", __func__, imms);
		return AARCH64_BREAK_FAULT;
	}
824 825 826 827 828 829 830 831 832

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_R, insn, immr);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, imms);
}
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851

u32 aarch64_insn_gen_movewide(enum aarch64_insn_register dst,
			      int imm, int shift,
			      enum aarch64_insn_variant variant,
			      enum aarch64_insn_movewide_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_MOVEWIDE_ZERO:
		insn = aarch64_insn_get_movz_value();
		break;
	case AARCH64_INSN_MOVEWIDE_KEEP:
		insn = aarch64_insn_get_movk_value();
		break;
	case AARCH64_INSN_MOVEWIDE_INVERSE:
		insn = aarch64_insn_get_movn_value();
		break;
	default:
852
		pr_err("%s: unknown movewide encoding %d\n", __func__, type);
853
		return AARCH64_BREAK_FAULT;
854 855
	}

856 857 858 859
	if (imm & ~(SZ_64K - 1)) {
		pr_err("%s: invalid immediate encoding %d\n", __func__, imm);
		return AARCH64_BREAK_FAULT;
	}
860 861 862

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
863 864 865 866 867
		if (shift != 0 && shift != 16) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
868 869 870
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
871 872 873 874 875
		if (shift != 0 && shift != 16 && shift != 32 && shift != 48) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
876 877
		break;
	default:
878
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
879
		return AARCH64_BREAK_FAULT;
880 881 882 883 884 885 886 887
	}

	insn |= (shift >> 4) << 21;

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm);
}
888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911

u32 aarch64_insn_gen_add_sub_shifted_reg(enum aarch64_insn_register dst,
					 enum aarch64_insn_register src,
					 enum aarch64_insn_register reg,
					 int shift,
					 enum aarch64_insn_variant variant,
					 enum aarch64_insn_adsb_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_ADSB_ADD:
		insn = aarch64_insn_get_add_value();
		break;
	case AARCH64_INSN_ADSB_SUB:
		insn = aarch64_insn_get_sub_value();
		break;
	case AARCH64_INSN_ADSB_ADD_SETFLAGS:
		insn = aarch64_insn_get_adds_value();
		break;
	case AARCH64_INSN_ADSB_SUB_SETFLAGS:
		insn = aarch64_insn_get_subs_value();
		break;
	default:
912
		pr_err("%s: unknown add/sub encoding %d\n", __func__, type);
913
		return AARCH64_BREAK_FAULT;
914 915 916 917
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
918 919 920 921 922
		if (shift & ~(SZ_32 - 1)) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
923 924 925
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
926 927 928 929 930
		if (shift & ~(SZ_64 - 1)) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
931 932
		break;
	default:
933
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
934
		return AARCH64_BREAK_FAULT;
935 936 937 938 939 940 941 942 943 944 945
	}


	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift);
}
946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961

u32 aarch64_insn_gen_data1(enum aarch64_insn_register dst,
			   enum aarch64_insn_register src,
			   enum aarch64_insn_variant variant,
			   enum aarch64_insn_data1_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_DATA1_REVERSE_16:
		insn = aarch64_insn_get_rev16_value();
		break;
	case AARCH64_INSN_DATA1_REVERSE_32:
		insn = aarch64_insn_get_rev32_value();
		break;
	case AARCH64_INSN_DATA1_REVERSE_64:
962 963 964 965 966
		if (variant != AARCH64_INSN_VARIANT_64BIT) {
			pr_err("%s: invalid variant for reverse64 %d\n",
			       __func__, variant);
			return AARCH64_BREAK_FAULT;
		}
967 968 969
		insn = aarch64_insn_get_rev64_value();
		break;
	default:
970
		pr_err("%s: unknown data1 encoding %d\n", __func__, type);
971
		return AARCH64_BREAK_FAULT;
972 973 974 975 976 977 978 979 980
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
981
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
982
		return AARCH64_BREAK_FAULT;
983 984 985 986 987 988
	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);
}
989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017

u32 aarch64_insn_gen_data2(enum aarch64_insn_register dst,
			   enum aarch64_insn_register src,
			   enum aarch64_insn_register reg,
			   enum aarch64_insn_variant variant,
			   enum aarch64_insn_data2_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_DATA2_UDIV:
		insn = aarch64_insn_get_udiv_value();
		break;
	case AARCH64_INSN_DATA2_SDIV:
		insn = aarch64_insn_get_sdiv_value();
		break;
	case AARCH64_INSN_DATA2_LSLV:
		insn = aarch64_insn_get_lslv_value();
		break;
	case AARCH64_INSN_DATA2_LSRV:
		insn = aarch64_insn_get_lsrv_value();
		break;
	case AARCH64_INSN_DATA2_ASRV:
		insn = aarch64_insn_get_asrv_value();
		break;
	case AARCH64_INSN_DATA2_RORV:
		insn = aarch64_insn_get_rorv_value();
		break;
	default:
1018
		pr_err("%s: unknown data2 encoding %d\n", __func__, type);
1019
		return AARCH64_BREAK_FAULT;
1020 1021 1022 1023 1024 1025 1026 1027 1028
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
1029
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
1030
		return AARCH64_BREAK_FAULT;
1031 1032 1033 1034 1035 1036 1037 1038
	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);
}
1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056

u32 aarch64_insn_gen_data3(enum aarch64_insn_register dst,
			   enum aarch64_insn_register src,
			   enum aarch64_insn_register reg1,
			   enum aarch64_insn_register reg2,
			   enum aarch64_insn_variant variant,
			   enum aarch64_insn_data3_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_DATA3_MADD:
		insn = aarch64_insn_get_madd_value();
		break;
	case AARCH64_INSN_DATA3_MSUB:
		insn = aarch64_insn_get_msub_value();
		break;
	default:
1057
		pr_err("%s: unknown data3 encoding %d\n", __func__, type);
1058
		return AARCH64_BREAK_FAULT;
1059 1060 1061 1062 1063 1064 1065 1066 1067
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
1068
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
1069
		return AARCH64_BREAK_FAULT;
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081
	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RA, insn, src);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
					    reg1);

	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn,
					    reg2);
}
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117

u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst,
					 enum aarch64_insn_register src,
					 enum aarch64_insn_register reg,
					 int shift,
					 enum aarch64_insn_variant variant,
					 enum aarch64_insn_logic_type type)
{
	u32 insn;

	switch (type) {
	case AARCH64_INSN_LOGIC_AND:
		insn = aarch64_insn_get_and_value();
		break;
	case AARCH64_INSN_LOGIC_BIC:
		insn = aarch64_insn_get_bic_value();
		break;
	case AARCH64_INSN_LOGIC_ORR:
		insn = aarch64_insn_get_orr_value();
		break;
	case AARCH64_INSN_LOGIC_ORN:
		insn = aarch64_insn_get_orn_value();
		break;
	case AARCH64_INSN_LOGIC_EOR:
		insn = aarch64_insn_get_eor_value();
		break;
	case AARCH64_INSN_LOGIC_EON:
		insn = aarch64_insn_get_eon_value();
		break;
	case AARCH64_INSN_LOGIC_AND_SETFLAGS:
		insn = aarch64_insn_get_ands_value();
		break;
	case AARCH64_INSN_LOGIC_BIC_SETFLAGS:
		insn = aarch64_insn_get_bics_value();
		break;
	default:
1118
		pr_err("%s: unknown logical encoding %d\n", __func__, type);
1119
		return AARCH64_BREAK_FAULT;
1120 1121 1122 1123
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
1124 1125 1126 1127 1128
		if (shift & ~(SZ_32 - 1)) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
1129 1130 1131
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		insn |= AARCH64_INSN_SF_BIT;
1132 1133 1134 1135 1136
		if (shift & ~(SZ_64 - 1)) {
			pr_err("%s: invalid shift encoding %d\n", __func__,
			       shift);
			return AARCH64_BREAK_FAULT;
		}
1137 1138
		break;
	default:
1139
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
1140
		return AARCH64_BREAK_FAULT;
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
	}


	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, reg);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift);
}
1152

1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
/*
 * Decode the imm field of a branch, and return the byte offset as a
 * signed value (so it can be used when computing a new branch
 * target).
 */
s32 aarch64_get_branch_offset(u32 insn)
{
	s32 imm;

	if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) {
		imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn);
		return (imm << 6) >> 4;
	}

	if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
	    aarch64_insn_is_bcond(insn)) {
		imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn);
		return (imm << 13) >> 11;
	}

	if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) {
		imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn);
		return (imm << 18) >> 16;
	}

	/* Unhandled instruction */
	BUG();
}

/*
 * Encode the displacement of a branch in the imm field and return the
 * updated instruction.
 */
u32 aarch64_set_branch_offset(u32 insn, s32 offset)
{
	if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn))
		return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn,
						     offset >> 2);

	if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) ||
	    aarch64_insn_is_bcond(insn))
		return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
						     offset >> 2);

	if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn))
		return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn,
						     offset >> 2);

	/* Unhandled instruction */
	BUG();
}

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/*
 * Extract the Op/CR data from a msr/mrs instruction.
 */
u32 aarch64_insn_extract_system_reg(u32 insn)
{
	return (insn & 0x1FFFE0) >> 5;
}

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bool aarch32_insn_is_wide(u32 insn)
{
	return insn >= 0xe800;
}
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/*
 * Macros/defines for extracting register numbers from instruction.
 */
u32 aarch32_insn_extract_reg_num(u32 insn, int offset)
{
	return (insn & (0xf << offset)) >> offset;
}
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#define OPC2_MASK	0x7
#define OPC2_OFFSET	5
u32 aarch32_insn_mcr_extract_opc2(u32 insn)
{
	return (insn & (OPC2_MASK << OPC2_OFFSET)) >> OPC2_OFFSET;
}

#define CRM_MASK	0xf
u32 aarch32_insn_mcr_extract_crm(u32 insn)
{
	return insn & CRM_MASK;
}
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static bool __kprobes __check_eq(unsigned long pstate)
{
	return (pstate & PSR_Z_BIT) != 0;
}

static bool __kprobes __check_ne(unsigned long pstate)
{
	return (pstate & PSR_Z_BIT) == 0;
}

static bool __kprobes __check_cs(unsigned long pstate)
{
	return (pstate & PSR_C_BIT) != 0;
}

static bool __kprobes __check_cc(unsigned long pstate)
{
	return (pstate & PSR_C_BIT) == 0;
}

static bool __kprobes __check_mi(unsigned long pstate)
{
	return (pstate & PSR_N_BIT) != 0;
}

static bool __kprobes __check_pl(unsigned long pstate)
{
	return (pstate & PSR_N_BIT) == 0;
}

static bool __kprobes __check_vs(unsigned long pstate)
{
	return (pstate & PSR_V_BIT) != 0;
}

static bool __kprobes __check_vc(unsigned long pstate)
{
	return (pstate & PSR_V_BIT) == 0;
}

static bool __kprobes __check_hi(unsigned long pstate)
{
	pstate &= ~(pstate >> 1);	/* PSR_C_BIT &= ~PSR_Z_BIT */
	return (pstate & PSR_C_BIT) != 0;
}

static bool __kprobes __check_ls(unsigned long pstate)
{
	pstate &= ~(pstate >> 1);	/* PSR_C_BIT &= ~PSR_Z_BIT */
	return (pstate & PSR_C_BIT) == 0;
}

static bool __kprobes __check_ge(unsigned long pstate)
{
	pstate ^= (pstate << 3);	/* PSR_N_BIT ^= PSR_V_BIT */
	return (pstate & PSR_N_BIT) == 0;
}

static bool __kprobes __check_lt(unsigned long pstate)
{
	pstate ^= (pstate << 3);	/* PSR_N_BIT ^= PSR_V_BIT */
	return (pstate & PSR_N_BIT) != 0;
}

static bool __kprobes __check_gt(unsigned long pstate)
{
	/*PSR_N_BIT ^= PSR_V_BIT */
	unsigned long temp = pstate ^ (pstate << 3);

	temp |= (pstate << 1);	/*PSR_N_BIT |= PSR_Z_BIT */
	return (temp & PSR_N_BIT) == 0;
}

static bool __kprobes __check_le(unsigned long pstate)
{
	/*PSR_N_BIT ^= PSR_V_BIT */
	unsigned long temp = pstate ^ (pstate << 3);

	temp |= (pstate << 1);	/*PSR_N_BIT |= PSR_Z_BIT */
	return (temp & PSR_N_BIT) != 0;
}

static bool __kprobes __check_al(unsigned long pstate)
{
	return true;
}

/*
 * Note that the ARMv8 ARM calls condition code 0b1111 "nv", but states that
 * it behaves identically to 0b1110 ("al").
 */
pstate_check_t * const aarch32_opcode_cond_checks[16] = {
	__check_eq, __check_ne, __check_cs, __check_cc,
	__check_mi, __check_pl, __check_vs, __check_vc,
	__check_hi, __check_ls, __check_ge, __check_lt,
	__check_gt, __check_le, __check_al, __check_al
};