Re: [PATCH v3 2/5] arm64: Kprobes instruction simulation support

From: William Cohen
Date: Tue Nov 18 2014 - 09:44:29 EST

On 11/18/2014 01:32 AM, David Long wrote:
> From: Sandeepa Prabhu <sandeepa.prabhu@xxxxxxxxxx>
>
> Add support for AArch64 instruction simulation in kprobes.
>
> Kprobes need simulation of instructions that cannot be stepped
> right-away from different memory location. i.e. those instructions
> that uses PC-relative addressing. In simulation, the behaviour
> of the instruction is implemented using copy of pt_regs.
>
> Following instruction catagories are simulated:
> - All branching instructions(conditional, register, and immediate)
> - Literal access instructions(load-literal, adr/adrp)
>
> conditional execution are limited to branching instructions in
> ARM v8. If conditions at PSTATE does not match the condition fields
> of opcode, the instruction is effectively NOP. Kprobes consider
> this case as 'miss'.
>
> changes since v4:
> from David A. Long:
> 1) Fix bogus simulate_ldrsw_literal() semantics.
> from Will Cohen:
> 2) Remove PC adjustments when simulating an instruction.

Add missing PC updates for some instruction simulation.

> 3) Fix displacement calculations.
>
> Signed-off-by: Sandeepa Prabhu <sandeepa.prabhu@xxxxxxxxxx>
> Signed-off-by: William Cohen <wcohen@xxxxxxxxxx>
> Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>
> ---
> arch/arm64/kernel/Makefile | 4 +-
> arch/arm64/kernel/kprobes-arm64.c | 120 +++++++++++++++++++--
> arch/arm64/kernel/kprobes-arm64.h | 2 +
> arch/arm64/kernel/kprobes.c | 35 ++++++-
> arch/arm64/kernel/probes-condn-check.c | 122 ++++++++++++++++++++++
> arch/arm64/kernel/probes-simulate-insn.c | 174 +++++++++++++++++++++++++++++++
> arch/arm64/kernel/probes-simulate-insn.h | 33 ++++++
> 7 files changed, 477 insertions(+), 13 deletions(-)
> create mode 100644 arch/arm64/kernel/probes-condn-check.c
> create mode 100644 arch/arm64/kernel/probes-simulate-insn.c
> create mode 100644 arch/arm64/kernel/probes-simulate-insn.h
>
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index df08c0e..fc9922f 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -29,7 +29,9 @@ arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND) += sleep.o suspend.o
> arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o
> arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o
> arm64-obj-$(CONFIG_KGDB) += kgdb.o
> -arm64-obj-$(CONFIG_KPROBES) += kprobes.o kprobes-arm64.o
> +arm64-obj-$(CONFIG_KPROBES) += kprobes.o kprobes-arm64.o \
> + probes-simulate-insn.o \
> + probes-condn-check.o
> arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o
> arm64-obj-$(CONFIG_PCI) += pci.o
>
> diff --git a/arch/arm64/kernel/kprobes-arm64.c b/arch/arm64/kernel/kprobes-arm64.c
> index 30d1c14..bee7816 100644
> --- a/arch/arm64/kernel/kprobes-arm64.c
> +++ b/arch/arm64/kernel/kprobes-arm64.c
> @@ -20,6 +20,101 @@
>
> #include "probes-decode.h"
> #include "kprobes-arm64.h"
> +#include "probes-simulate-insn.h"
> +
> +/*
> + * condition check functions for kprobes simulation
> + */
> +static unsigned long __kprobes
> +__check_pstate(struct kprobe *p, struct pt_regs *regs)
> +{
> + struct arch_specific_insn *asi = &p->ainsn;
> + unsigned long pstate = regs->pstate & 0xffffffff;
> +
> + return asi->pstate_cc(pstate);
> +}
> +
> +static unsigned long __kprobes
> +__check_cbz(struct kprobe *p, struct pt_regs *regs)
> +{
> + return check_cbz((u32)p->opcode, regs);
> +}
> +
> +static unsigned long __kprobes
> +__check_cbnz(struct kprobe *p, struct pt_regs *regs)
> +{
> + return check_cbnz((u32)p->opcode, regs);
> +}
> +
> +static unsigned long __kprobes
> +__check_tbz(struct kprobe *p, struct pt_regs *regs)
> +{
> + return check_tbz((u32)p->opcode, regs);
> +}
> +
> +static unsigned long __kprobes
> +__check_tbnz(struct kprobe *p, struct pt_regs *regs)
> +{
> + return check_tbnz((u32)p->opcode, regs);
> +}
> +
> +/*
> + * prepare functions for instruction simulation
> + */
> +static void __kprobes
> +prepare_none(struct kprobe *p, struct arch_specific_insn *asi)
> +{
> +}
> +
> +static void __kprobes
> +prepare_bcond(struct kprobe *p, struct arch_specific_insn *asi)
> +{
> + kprobe_opcode_t insn = p->opcode;
> +
> + asi->check_condn = __check_pstate;
> + asi->pstate_cc = kprobe_condition_checks[insn & 0xf];
> +}
> +
> +static void __kprobes
> +prepare_cbz_cbnz(struct kprobe *p, struct arch_specific_insn *asi)
> +{
> + kprobe_opcode_t insn = p->opcode;
> +
> + asi->check_condn = (insn & (1 << 24)) ? __check_cbnz : __check_cbz;
> +}
> +
> +static void __kprobes
> +prepare_tbz_tbnz(struct kprobe *p, struct arch_specific_insn *asi)
> +{
> + kprobe_opcode_t insn = p->opcode;
> +
> + asi->check_condn = (insn & (1 << 24)) ? __check_tbnz : __check_tbz;
> +}
> +
> +
> +/* Load literal (PC-relative) instructions
> + * Encoding: xx01 1x00 xxxx xxxx xxxx xxxx xxxx xxxx
> + *
> + * opcode[26]: V=0, Load GP registers, simulate them.
> + * Encoding: xx01 1000 xxxx xxxx xxxx xxxx xxxx xxxx
> + * opcode[31:30]: op = 00, 01 - LDR literal
> + * opcode[31:30]: op = 10, - LDRSW literal
> + *
> + * 1. V=1 -Load FP/AdvSIMD registers
> + * Encoding: xx01 1100 xxxx xxxx xxxx xxxx xxxx xxxx
> + * 2. V=0,opc=11 -PRFM(Prefetch literal)
> + * Encoding: 1101 1000 xxxx xxxx xxxx xxxx xxxx xxxx
> + * Reject FP/AdvSIMD literal load & PRFM literal.
> + */
> +static const struct aarch64_decode_item load_literal_subtable[] = {
> + DECODE_REJECT(0x1C000000, 0x3F000000),
> + DECODE_REJECT(0xD8000000, 0xFF000000),
> + DECODE_LITERAL(0x18000000, 0xBF000000, prepare_none,
> + simulate_ldr_literal),
> + DECODE_LITERAL(0x98000000, 0xFF000000, prepare_none,
> + simulate_ldrsw_literal),
> + DECODE_END,
> +};
>
> /* AArch64 instruction decode table for kprobes:
> * The instruction will fall into one of the 3 groups:
> @@ -43,7 +138,8 @@ static const struct aarch64_decode_item aarch64_decode_table[] = {
> * Data processing - PC relative(literal) addressing:
> * Encoding: xxx1 0000 xxxx xxxx xxxx xxxx xxxx xxxx
> */
> - DECODE_REJECT(0x10000000, 0x1F000000),
> + DECODE_LITERAL(0x10000000, 0x1F000000, prepare_none,
> + simulate_adr_adrp),
>
> /*
> * Data processing - Add/Substract Immediate:
> @@ -83,12 +179,16 @@ static const struct aarch64_decode_item aarch64_decode_table[] = {
> * 0101 010x xxxx xxxx xxxx xxxx xxxx xxxx (Conditional, immediate)
> * 1101 011x xxxx xxxx xxxx xxxx xxxx xxxx (Unconditional,register)
> */
> - DECODE_REJECT(0x14000000, 0x7C000000),
> - DECODE_REJECT(0x14000000, 0x7C000000),
> - DECODE_REJECT(0x34000000, 0x7E000000),
> - DECODE_REJECT(0x36000000, 0x7E000000),
> - DECODE_REJECT(0x54000000, 0xFE000000),
> - DECODE_REJECT(0xD6000000, 0xFE000000),
> + DECODE_BRANCH(0x14000000, 0x7C000000, prepare_none,
> + simulate_b_bl),
> + DECODE_BRANCH(0x34000000, 0x7E000000, prepare_cbz_cbnz,
> + simulate_cbz_cbnz),
> + DECODE_BRANCH(0x36000000, 0x7E000000, prepare_tbz_tbnz,
> + simulate_tbz_tbnz),
> + DECODE_BRANCH(0x54000000, 0xFE000000, prepare_bcond,
> + simulate_b_cond),
> + DECODE_BRANCH(0xD6000000, 0xFE000000, prepare_none,
> + simulate_br_blr_ret),
>
> /* System insn:
> * Encoding: 1101 0101 00xx xxxx xxxx xxxx xxxx xxxx
> @@ -119,7 +219,7 @@ static const struct aarch64_decode_item aarch64_decode_table[] = {
> * Load/Store - PC relative(literal):
> * Encoding: xx01 1x00 xxxx xxxx xxxx xxxx xxxx xxxx
> */
> - DECODE_REJECT(0x18000000, 0x3B000000),
> + DECODE_TABLE(0x18000000, 0x3B000000, load_literal_subtable),
>
> /*
> * Load/Store - Register Pair
> @@ -188,7 +288,9 @@ kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
> break;
>
> case DECODE_TYPE_SIMULATE:
> - ret = INSN_REJECTED;
> + asi->prepare = decode_prepare_fn(tbl[entry]);
> + asi->handler = decode_handler_fn(tbl[entry]);
> + ret = INSN_GOOD_NO_SLOT;
> break;
>
> case DECODE_TYPE_TABLE:
> diff --git a/arch/arm64/kernel/kprobes-arm64.h b/arch/arm64/kernel/kprobes-arm64.h
> index 87e7891..ff8a55f 100644
> --- a/arch/arm64/kernel/kprobes-arm64.h
> +++ b/arch/arm64/kernel/kprobes-arm64.h
> @@ -22,6 +22,8 @@ enum kprobe_insn {
> INSN_GOOD,
> };
>
> +extern kprobes_pstate_check_t * const kprobe_condition_checks[16];
> +
> enum kprobe_insn __kprobes
> arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi);
>
> diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c
> index ca7fa10..789ab61 100644
> --- a/arch/arm64/kernel/kprobes.c
> +++ b/arch/arm64/kernel/kprobes.c
> @@ -38,6 +38,9 @@
> DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
> DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
>
> +static void __kprobes
> +post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
> +
> static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
> {
> /* prepare insn slot */
> @@ -54,6 +57,27 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
> p->ainsn.restore.type = RESTORE_PC;
> }
>
> +static void __kprobes arch_prepare_simulate(struct kprobe *p)
> +{
> + if (p->ainsn.prepare)
> + p->ainsn.prepare(p, &p->ainsn);
> +
> + /* This instructions is not executed xol. No need to adjust the PC */
> + p->ainsn.restore.addr = 0;
> + p->ainsn.restore.type = NO_RESTORE;
> +}
> +
> +static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
> +{
> + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
> +
> + if (p->ainsn.handler)
> + p->ainsn.handler((u32)p->opcode, (long)p->addr, regs);
> +
> + /* single step simulated, now go for post processing */
> + post_kprobe_handler(kcb, regs);
> +}
> +
> int __kprobes arch_prepare_kprobe(struct kprobe *p)
> {
> kprobe_opcode_t insn;
> @@ -72,7 +96,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
> return -EINVAL;
>
> case INSN_GOOD_NO_SLOT: /* insn need simulation */
> - return -EINVAL;
> + p->ainsn.insn = NULL;
> + break;
>
> case INSN_GOOD: /* instruction uses slot */
> p->ainsn.insn = get_insn_slot();
> @@ -82,7 +107,10 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
> };
>
> /* prepare the instruction */
> - arch_prepare_ss_slot(p);
> + if (p->ainsn.insn)
> + arch_prepare_ss_slot(p);
> + else
> + arch_prepare_simulate(p);
>
> return 0;
> }
> @@ -235,7 +263,8 @@ static void __kprobes setup_singlestep(struct kprobe *p,
> kernel_enable_single_step(regs);
> instruction_pointer(regs) = slot;
> } else {
> - BUG();
> + /* insn simulation */
> + arch_simulate_insn(p, regs);
> }
> }
>
> diff --git a/arch/arm64/kernel/probes-condn-check.c b/arch/arm64/kernel/probes-condn-check.c
> new file mode 100644
> index 0000000..e68aa0c
> --- /dev/null
> +++ b/arch/arm64/kernel/probes-condn-check.c
> @@ -0,0 +1,122 @@
> +/*
> + * arch/arm64/kernel/probes-condn-check.c
> + *
> + * Copyright (C) 2013 Linaro Limited
> + *
> + * Copied from: arch/arm/kernel/kprobes-common.c
> + *
> + * 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.
> + *
> + * Description:
> + *
> + * AArch64 and AArch32 shares same conditional(CNZV) flags encoding.
> + * This file implements conditional check helpers compatible with
> + * both AArch64 and AArch32 modes. Uprobes on v8 can handle both 32-bit
> + * & 64-bit user-space instructions, so we abstract the common functions
> + * in this file. While AArch64 and AArch32 specific instruction handling
> + * are implemented in separate files, this file contains common bits.
> + */
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <asm/probes.h>
> +
> +static unsigned long __kprobes __check_eq(unsigned long pstate)
> +{
> + return pstate & PSR_Z_BIT;
> +}
> +
> +static unsigned long __kprobes __check_ne(unsigned long pstate)
> +{
> + return (~pstate) & PSR_Z_BIT;
> +}
> +
> +static unsigned long __kprobes __check_cs(unsigned long pstate)
> +{
> + return pstate & PSR_C_BIT;
> +}
> +
> +static unsigned long __kprobes __check_cc(unsigned long pstate)
> +{
> + return (~pstate) & PSR_C_BIT;
> +}
> +
> +static unsigned long __kprobes __check_mi(unsigned long pstate)
> +{
> + return pstate & PSR_N_BIT;
> +}
> +
> +static unsigned long __kprobes __check_pl(unsigned long pstate)
> +{
> + return (~pstate) & PSR_N_BIT;
> +}
> +
> +static unsigned long __kprobes __check_vs(unsigned long pstate)
> +{
> + return pstate & PSR_V_BIT;
> +}
> +
> +static unsigned long __kprobes __check_vc(unsigned long pstate)
> +{
> + return (~pstate) & PSR_V_BIT;
> +}
> +
> +static unsigned long __kprobes __check_hi(unsigned long pstate)
> +{
> + pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
> + return pstate & PSR_C_BIT;
> +}
> +
> +static unsigned long __kprobes __check_ls(unsigned long pstate)
> +{
> + pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
> + return (~pstate) & PSR_C_BIT;
> +}
> +
> +static unsigned long __kprobes __check_ge(unsigned long pstate)
> +{
> + pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
> + return (~pstate) & PSR_N_BIT;
> +}
> +
> +static unsigned long __kprobes __check_lt(unsigned long pstate)
> +{
> + pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
> + return pstate & PSR_N_BIT;
> +}
> +
> +static unsigned long __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;
> +}
> +
> +static unsigned long __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;
> +}
> +
> +static unsigned long __kprobes __check_al(unsigned long pstate)
> +{
> + return true;
> +}
> +
> +kprobes_pstate_check_t * const kprobe_condition_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
> +};
> diff --git a/arch/arm64/kernel/probes-simulate-insn.c b/arch/arm64/kernel/probes-simulate-insn.c
> new file mode 100644
> index 0000000..a224c91
> --- /dev/null
> +++ b/arch/arm64/kernel/probes-simulate-insn.c
> @@ -0,0 +1,174 @@
> +/*
> + * arch/arm64/kernel/probes-simulate-insn.c
> + *
> + * Copyright (C) 2013 Linaro Limited.
> + *
> + * 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.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/kprobes.h>
> +#include <linux/module.h>
> +
> +#include "probes-simulate-insn.h"
> +
> +#define sign_extend(x, signbit) \
> + ((x) | (0 - ((x) & (1 << (signbit)))))
> +
> +#define bbl_displacement(insn) \
> + sign_extend(((insn) & 0x3ffffff) << 2, 27)
> +
> +#define bcond_displacement(insn) \
> + sign_extend(((insn >> 5) & 0x7ffff) << 2, 21)
> +
> +#define cbz_displacement(insn) \
> + sign_extend(((insn >> 5) & 0x7ffff) << 2, 21)
> +
> +#define tbz_displacement(insn) \
> + sign_extend(((insn >> 5) & 0x3fff) << 2, 15)
> +
> +#define ldr_displacement(insn) \
> + sign_extend(((insn >> 5) & 0x7ffff) << 2, 21)
> +
> +
> +unsigned long __kprobes check_cbz(u32 opcode, struct pt_regs *regs)
> +{
> + int xn = opcode & 0x1f;
> +
> + return (opcode & (1 << 31)) ?
> + !(regs->regs[xn]) : !(regs->regs[xn] & 0xffffffff);
> +}
> +
> +unsigned long __kprobes check_cbnz(u32 opcode, struct pt_regs *regs)
> +{
> + int xn = opcode & 0x1f;
> +
> + return (opcode & (1 << 31)) ?
> + (regs->regs[xn]) : (regs->regs[xn] & 0xffffffff);
> +}
> +
> +unsigned long __kprobes check_tbz(u32 opcode, struct pt_regs *regs)
> +{
> + int xn = opcode & 0x1f;
> + int bit_pos = ((opcode & (1 << 31)) >> 26) | ((opcode >> 19) & 0x1f);
> +
> + return ~((regs->regs[xn] >> bit_pos) & 0x1);
> +}
> +
> +unsigned long __kprobes check_tbnz(u32 opcode, struct pt_regs *regs)
> +{
> + int xn = opcode & 0x1f;
> + int bit_pos = ((opcode & (1 << 31)) >> 26) | ((opcode >> 19) & 0x1f);
> +
> + return (regs->regs[xn] >> bit_pos) & 0x1;
> +}
> +
> +/*
> + * instruction simulate functions
> + */
> +void __kprobes simulate_none(u32 opcode, long addr, struct pt_regs *regs)
> +{
> +}
> +
> +void __kprobes
> +simulate_adr_adrp(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + long imm, xn, val;
> +
> + xn = opcode & 0x1f;
> + imm = ((opcode >> 3) & 0x1ffffc) | ((opcode >> 29) & 0x3);
> + imm = sign_extend(imm, 20);
> + if (opcode & 0x80000000)
> + val = (imm<<12) + (addr & 0xfffffffffffff000);
> + else
> + val = imm + addr;
> +
> + regs->regs[xn] = val;
> +
> + instruction_pointer(regs) += 4;
> +}
> +
> +void __kprobes
> +simulate_b_bl(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + int disp = bbl_displacement(opcode);
> +
> + /* Link register is x30 */
> + if (opcode & (1 << 31))
> + regs->regs[30] = addr + 4;
> +
> + instruction_pointer(regs) = addr + disp;
> +}
> +
> +void __kprobes
> +simulate_b_cond(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + int disp = bcond_displacement(opcode);
> +
> + instruction_pointer(regs) = addr + disp;
> +}
> +
> +void __kprobes
> +simulate_br_blr_ret(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + int xn = (opcode >> 5) & 0x1f;
> +
> + /* Link register is x30 */
> + if (((opcode >> 21) & 0x3) == 1)
> + regs->regs[30] = addr + 4;
> +
> + instruction_pointer(regs) = regs->regs[xn];
> +}
> +
> +void __kprobes
> +simulate_cbz_cbnz(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + int disp = cbz_displacement(opcode);
> +
> + instruction_pointer(regs) = addr + disp;
> +}
> +
> +void __kprobes
> +simulate_tbz_tbnz(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + int disp = tbz_displacement(opcode);
> +
> + instruction_pointer(regs) = addr + disp;
> +}
> +
> +void __kprobes
> +simulate_ldr_literal(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + u64 *load_addr;
> + int xn = opcode & 0x1f;
> + int disp = ldr_displacement(opcode);
> +
> + load_addr = (u64 *) (addr + disp);
> +
> + if (opcode & (1 << 30)) /* x0-x31 */
> + regs->regs[xn] = *load_addr;
> + else /* w0-w31 */
> + *(u32 *) (&regs->regs[xn]) = (*(u32 *) (load_addr));
> +
> + instruction_pointer(regs) += 4;
> +}
> +
> +void __kprobes
> +simulate_ldrsw_literal(u32 opcode, long addr, struct pt_regs *regs)
> +{
> + s32 *load_addr;
> + int xn = opcode & 0x1f;
> + int disp = ldr_displacement(opcode);
> +
> + load_addr = (s32 *) (addr + disp);
> + regs->regs[xn] = *load_addr;
> +
> + instruction_pointer(regs) += 4;
> +}
> diff --git a/arch/arm64/kernel/probes-simulate-insn.h b/arch/arm64/kernel/probes-simulate-insn.h
> new file mode 100644
> index 0000000..406f5c2
> --- /dev/null
> +++ b/arch/arm64/kernel/probes-simulate-insn.h
> @@ -0,0 +1,33 @@
> +/*
> + * arch/arm64/kernel/probes-simulate-insn.h
> + *
> + * Copyright (C) 2013 Linaro Limited
> + *
> + * 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.
> + */
> +
> +#ifndef _ARM_KERNEL_PROBES_SIMULATE_INSN_H
> +#define _ARM_KERNEL_PROBES_SIMULATE_INSN_H
> +
> +unsigned long check_cbz(u32 opcode, struct pt_regs *regs);
> +unsigned long check_cbnz(u32 opcode, struct pt_regs *regs);
> +unsigned long check_tbz(u32 opcode, struct pt_regs *regs);
> +unsigned long check_tbnz(u32 opcode, struct pt_regs *regs);
> +void simulate_none(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_adr_adrp(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_b_bl(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_b_cond(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_br_blr_ret(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_cbz_cbnz(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_tbz_tbnz(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_ldr_literal(u32 opcode, long addr, struct pt_regs *regs);
> +void simulate_ldrsw_literal(u32 opcode, long addr, struct pt_regs *regs);
> +
> +#endif /* _ARM_KERNEL_PROBES_SIMULATE_INSN_H */
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/