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Message-ID: <5476F82B.7010006@hitachi.com>
Date: Thu, 27 Nov 2014 19:08:43 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Wang Nan <wangnan0@...wei.com>
Cc: tixy@...aro.org, linux@....linux.org.uk, will.deacon@....com,
taras.kondratiuk@...aro.org, ben.dooks@...ethink.co.uk,
cl@...ux.com, rabin@....in, davem@...emloft.net,
lizefan@...wei.com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 2/4] ARM: kprobes: collects stack consumption for
store instructions
(2014/11/22 17:40), Wang Nan wrote:
> This patch uses the previously introduced checker functionality on
> store instructions to record their stack consumption information to
> arch_probes_insn.
>
> Signed-off-by: Wang Nan <wangnan0@...wei.com>
> Signed-off-by: Jon Medhurst <tixy@...aro.org>
> Reviewed-by: Jon Medhurst <tixy@...aro.org>
>From the viewpoint of kprobes, this looks good to me. It's now nicely separated
from kprobes core code :)
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Thank you,
>
> ---
>
> v1 -> v2:
> - Bugfix and code improvements following Tixy's suggestion. See:
> http://www.spinics.net/lists/arm-kernel/msg372912.html
>
> v2 -> v3:
> - Totaly reconstructed following Tixy' instruction. See:
> https://lkml.org/lkml/2014/10/27/662 .
> Add his SOB.
>
> v3 -> v4:
> - Commit message improvements.
> - Comments improvements and code cleanup.
> - A bug is found and fixed in decode table in arm_check_stack().
>
> v4 -> v5:
> - Bugs in thumb2 decoding table is found by Tixy and fixed.
> ---
> arch/arm/include/asm/probes.h | 1 +
> arch/arm/kernel/Makefile | 6 +-
> arch/arm/kernel/kprobes-arm.c | 3 +-
> arch/arm/kernel/kprobes-thumb.c | 5 +-
> arch/arm/kernel/probes-checkers-arm.c | 99 ++++++++++++++++++++++++++++
> arch/arm/kernel/probes-checkers-common.c | 101 ++++++++++++++++++++++++++++
> arch/arm/kernel/probes-checkers-thumb.c | 110 +++++++++++++++++++++++++++++++
> arch/arm/kernel/probes-checkers.h | 54 +++++++++++++++
> arch/arm/kernel/probes.c | 10 +++
> 9 files changed, 383 insertions(+), 6 deletions(-)
> create mode 100644 arch/arm/kernel/probes-checkers-arm.c
> create mode 100644 arch/arm/kernel/probes-checkers-common.c
> create mode 100644 arch/arm/kernel/probes-checkers-thumb.c
> create mode 100644 arch/arm/kernel/probes-checkers.h
>
> diff --git a/arch/arm/include/asm/probes.h b/arch/arm/include/asm/probes.h
> index 806cfe6..ccf9af3 100644
> --- a/arch/arm/include/asm/probes.h
> +++ b/arch/arm/include/asm/probes.h
> @@ -38,6 +38,7 @@ struct arch_probes_insn {
> probes_check_cc *insn_check_cc;
> probes_insn_singlestep_t *insn_singlestep;
> probes_insn_fn_t *insn_fn;
> + int stack_space;
> };
>
> #endif
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index 38ddd9f..45aed4b 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -52,11 +52,11 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
> obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o
> obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
> obj-$(CONFIG_UPROBES) += probes.o probes-arm.o uprobes.o uprobes-arm.o
> -obj-$(CONFIG_KPROBES) += probes.o kprobes.o kprobes-common.o patch.o
> +obj-$(CONFIG_KPROBES) += probes.o kprobes.o kprobes-common.o patch.o probes-checkers-common.o
> ifdef CONFIG_THUMB2_KERNEL
> -obj-$(CONFIG_KPROBES) += kprobes-thumb.o probes-thumb.o
> +obj-$(CONFIG_KPROBES) += kprobes-thumb.o probes-thumb.o probes-checkers-thumb.o
> else
> -obj-$(CONFIG_KPROBES) += kprobes-arm.o probes-arm.o
> +obj-$(CONFIG_KPROBES) += kprobes-arm.o probes-arm.o probes-checkers-arm.o
> endif
> obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o
> test-kprobes-objs := kprobes-test.o
> diff --git a/arch/arm/kernel/kprobes-arm.c b/arch/arm/kernel/kprobes-arm.c
> index 5a81275..56f78ce 100644
> --- a/arch/arm/kernel/kprobes-arm.c
> +++ b/arch/arm/kernel/kprobes-arm.c
> @@ -64,6 +64,7 @@
>
> #include "kprobes.h"
> #include "probes-arm.h"
> +#include "probes-checkers.h"
>
> #if __LINUX_ARM_ARCH__ >= 6
> #define BLX(reg) "blx "reg" \n\t"
> @@ -342,4 +343,4 @@ const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = {
> [PROBES_LDMSTM] = {.decoder = kprobe_decode_ldmstm}
> };
>
> -const struct decode_checker *kprobes_arm_checkers[] = {NULL};
> +const struct decode_checker *kprobes_arm_checkers[] = {arm_stack_checker, NULL};
> diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c
> index b8ba7d2..dbfd3ca 100644
> --- a/arch/arm/kernel/kprobes-thumb.c
> +++ b/arch/arm/kernel/kprobes-thumb.c
> @@ -15,6 +15,7 @@
>
> #include "kprobes.h"
> #include "probes-thumb.h"
> +#include "probes-checkers.h"
>
> /* These emulation encodings are functionally equivalent... */
> #define t32_emulate_rd8rn16rm0ra12_noflags \
> @@ -665,5 +666,5 @@ const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
> .handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
> };
>
> -const struct decode_checker *kprobes_t32_checkers[] = {NULL};
> -const struct decode_checker *kprobes_t16_checkers[] = {NULL};
> +const struct decode_checker *kprobes_t32_checkers[] = {t32_stack_checker, NULL};
> +const struct decode_checker *kprobes_t16_checkers[] = {t16_stack_checker, NULL};
> diff --git a/arch/arm/kernel/probes-checkers-arm.c b/arch/arm/kernel/probes-checkers-arm.c
> new file mode 100644
> index 0000000..53f6736
> --- /dev/null
> +++ b/arch/arm/kernel/probes-checkers-arm.c
> @@ -0,0 +1,99 @@
> +/*
> + * arch/arm/kernel/probes-checkers-arm.c
> + *
> + * Copyright (C) 2014 Huawei Inc.
> + *
> + * 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 "probes.h"
> +#include "probes-arm.h"
> +#include "probes-checkers.h"
> +
> +static enum probes_insn __kprobes arm_check_stack(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + /*
> + * PROBES_LDRSTRD, PROBES_LDMSTM, PROBES_STORE,
> + * PROBES_STORE_EXTRA may get here. Simply mark all normal
> + * insns as STACK_USE_NONE.
> + */
> + static const union decode_item table[] = {
> + /*
> + * 'STR{,D,B,H}, Rt, [Rn, Rm]' should be marked as UNKNOWN
> + * if Rn or Rm is SP.
> + * x
> + * STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx
> + * STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx
> + */
> + DECODE_OR (0x0e10000f, 0x0600000d),
> + DECODE_OR (0x0e1f0000, 0x060d0000),
> +
> + /*
> + * x
> + * STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx
> + * STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx
> + */
> + DECODE_OR (0x0e5000bf, 0x000000bd),
> + DECODE_CUSTOM (0x0e5f00b0, 0x000d00b0, STACK_USE_UNKNOWN),
> +
> + /*
> + * For PROBES_LDMSTM, only stmdx sp, [...] need to examine
> + *
> + * Bit B/A (bit 24) encodes arithmetic operation order. 1 means
> + * before, 0 means after.
> + * Bit I/D (bit 23) encodes arithmetic operation. 1 means
> + * increment, 0 means decrement.
> + *
> + * So:
> + * B I
> + * / /
> + * A D | Rn |
> + * STMDX SP, [...] cccc 100x 00x0 xxxx xxxx xxxx xxxx xxxx
> + */
> + DECODE_CUSTOM (0x0edf0000, 0x080d0000, STACK_USE_STMDX),
> +
> + /* P U W | Rn | Rt | imm12 |*/
> + /* STR (immediate) cccc 010x x0x0 1101 xxxx xxxx xxxx xxxx */
> + /* STRB (immediate) cccc 010x x1x0 1101 xxxx xxxx xxxx xxxx */
> + /* P U W | Rn | Rt |imm4| |imm4|*/
> + /* STRD (immediate) cccc 000x x1x0 1101 xxxx xxxx 1111 xxxx */
> + /* STRH (immediate) cccc 000x x1x0 1101 xxxx xxxx 1011 xxxx */
> + /*
> + * index = (P == '1'); add = (U == '1').
> + * Above insns with:
> + * index == 0 (str{,d,h} rx, [sp], #+/-imm) or
> + * add == 1 (str{,d,h} rx, [sp, #+<imm>])
> + * should be STACK_USE_NONE.
> + * Only str{,b,d,h} rx,[sp,#-n] (P == 1 and U == 0) are
> + * required to be examined.
> + */
> + /* STR{,B} Rt,[SP,#-n] cccc 0101 0xx0 1101 xxxx xxxx xxxx xxxx */
> + DECODE_CUSTOM (0x0f9f0000, 0x050d0000, STACK_USE_FIXED_XXX),
> +
> + /* STR{D,H} Rt,[SP,#-n] cccc 0001 01x0 1101 xxxx xxxx 1x11 xxxx */
> + DECODE_CUSTOM (0x0fdf00b0, 0x014d00b0, STACK_USE_FIXED_X0X),
> +
> + /* fall through */
> + DECODE_CUSTOM (0, 0, STACK_USE_NONE),
> + DECODE_END
> + };
> +
> + return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL);
> +}
> +
> +const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = {
> + [PROBES_LDRSTRD] = {.checker = arm_check_stack},
> + [PROBES_STORE_EXTRA] = {.checker = arm_check_stack},
> + [PROBES_STORE] = {.checker = arm_check_stack},
> + [PROBES_LDMSTM] = {.checker = arm_check_stack},
> +};
> diff --git a/arch/arm/kernel/probes-checkers-common.c b/arch/arm/kernel/probes-checkers-common.c
> new file mode 100644
> index 0000000..e9fd1b3
> --- /dev/null
> +++ b/arch/arm/kernel/probes-checkers-common.c
> @@ -0,0 +1,101 @@
> +/*
> + * arch/arm/kernel/probes-checkers-common.c
> + *
> + * Copyright (C) 2014 Huawei Inc.
> + *
> + * 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 "probes.h"
> +#include "probes-arm.h"
> +#include "probes-checkers.h"
> +
> +enum probes_insn checker_stack_use_none(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + asi->stack_space = 0;
> + return INSN_GOOD_NO_SLOT;
> +}
> +
> +enum probes_insn checker_stack_use_unknown(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + asi->stack_space = -1;
> + return INSN_GOOD_NO_SLOT;
> +}
> +
> +#ifdef CONFIG_THUMB2_KERNEL
> +enum probes_insn checker_stack_use_imm_0xx(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + int imm = insn & 0xff;
> + asi->stack_space = imm;
> + return INSN_GOOD_NO_SLOT;
> +}
> +
> +/*
> + * Different from other insn uses imm8, the real addressing offset of
> + * STRD in T32 encoding should be imm8 * 4. See ARMARM description.
> + */
> +enum probes_insn checker_stack_use_t32strd(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + int imm = insn & 0xff;
> + asi->stack_space = imm << 2;
> + return INSN_GOOD_NO_SLOT;
> +}
> +#else
> +enum probes_insn checker_stack_use_imm_x0x(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + int imm = ((insn & 0xf00) >> 4) + (insn & 0xf);
> + asi->stack_space = imm;
> + return INSN_GOOD_NO_SLOT;
> +}
> +#endif
> +
> +enum probes_insn checker_stack_use_imm_xxx(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + int imm = insn & 0xfff;
> + asi->stack_space = imm;
> + return INSN_GOOD_NO_SLOT;
> +}
> +
> +enum probes_insn checker_stack_use_stmdx(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + unsigned int reglist = insn & 0xffff;
> + int pbit = insn & (1 << 24);
> + asi->stack_space = (hweight32(reglist) - (!pbit ? 1 : 0)) * 4;
> +
> + return INSN_GOOD_NO_SLOT;
> +}
> +
> +const union decode_action stack_check_actions[] = {
> + [STACK_USE_NONE] = {.decoder = checker_stack_use_none},
> + [STACK_USE_UNKNOWN] = {.decoder = checker_stack_use_unknown},
> +#ifdef CONFIG_THUMB2_KERNEL
> + [STACK_USE_FIXED_0XX] = {.decoder = checker_stack_use_imm_0xx},
> + [STACK_USE_T32STRD] = {.decoder = checker_stack_use_t32strd},
> +#else
> + [STACK_USE_FIXED_X0X] = {.decoder = checker_stack_use_imm_x0x},
> +#endif
> + [STACK_USE_FIXED_XXX] = {.decoder = checker_stack_use_imm_xxx},
> + [STACK_USE_STMDX] = {.decoder = checker_stack_use_stmdx},
> +};
> diff --git a/arch/arm/kernel/probes-checkers-thumb.c b/arch/arm/kernel/probes-checkers-thumb.c
> new file mode 100644
> index 0000000..e43ac08
> --- /dev/null
> +++ b/arch/arm/kernel/probes-checkers-thumb.c
> @@ -0,0 +1,110 @@
> +/*
> + * arch/arm/kernel/probes-checkers-arm.c
> + *
> + * Copyright (C) 2014 Huawei Inc.
> + *
> + * 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 "probes.h"
> +#include "probes-thumb.h"
> +#include "probes-checkers.h"
> +
> +static enum probes_insn __kprobes t32_check_stack(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + /*
> + * PROBES_T32_LDMSTM, PROBES_T32_LDRDSTRD and PROBES_T32_LDRSTR
> + * may get here. Simply mark all normal insns as STACK_USE_NONE.
> + */
> + static const union decode_item table[] = {
> +
> + /*
> + * First, filter out all ldr insns to make our life easier.
> + * Following load insns may come here:
> + * LDM, LDRD, LDR.
> + * In T32 encoding, bit 20 is enough for distinguishing
> + * load and store. All load insns have this bit set, when
> + * all store insns have this bit clear.
> + */
> + DECODE_CUSTOM (0x00100000, 0x00100000, STACK_USE_NONE),
> +
> + /*
> + * Mark all 'STR{,B,H}, Rt, [Rn, Rm]' as STACK_USE_UNKNOWN
> + * if Rn or Rm is SP. T32 doesn't encode STRD.
> + */
> + /* xx | Rn | Rt | | Rm |*/
> + /* STR (register) 1111 1000 0100 xxxx xxxx 0000 00xx xxxx */
> + /* STRB (register) 1111 1000 0000 xxxx xxxx 0000 00xx xxxx */
> + /* STRH (register) 1111 1000 0010 xxxx xxxx 0000 00xx xxxx */
> + /* INVALID INSN 1111 1000 0110 xxxx xxxx 0000 00xx xxxx */
> + /* By Introducing INVALID INSN, bit 21 and 22 can be ignored. */
> + DECODE_OR (0xff9f0fc0, 0xf80d0000),
> + DECODE_CUSTOM (0xff900fcf, 0xf800000d, STACK_USE_UNKNOWN),
> +
> +
> + /* xx | Rn | Rt | PUW| imm8 |*/
> + /* STR (imm 8) 1111 1000 0100 1101 xxxx 110x xxxx xxxx */
> + /* STRB (imm 8) 1111 1000 0000 1101 xxxx 110x xxxx xxxx */
> + /* STRH (imm 8) 1111 1000 0010 1101 xxxx 110x xxxx xxxx */
> + /* INVALID INSN 1111 1000 0110 1101 xxxx 110x xxxx xxxx */
> + /* Only consider U == 0 and P == 1: strx rx, [sp, #-<imm>] */
> + DECODE_CUSTOM (0xff9f0e00, 0xf80d0c00, STACK_USE_FIXED_0XX),
> +
> + /* For STR{,B,H} (imm 12), offset is always positive, so ignore them. */
> +
> + /* P U W | Rn | Rt | Rt2| imm8 |*/
> + /* STRD (immediate) 1110 1001 01x0 1101 xxxx xxxx xxxx xxxx */
> + /*
> + * Only consider U == 0 and P == 1.
> + * Also note that STRD in T32 encoding is special:
> + * imm = ZeroExtend(imm8:'00', 32)
> + */
> + DECODE_CUSTOM (0xffdf0000, 0xe94d0000, STACK_USE_T32STRD),
> +
> + /* | Rn | */
> + /* STMDB 1110 1001 00x0 1101 xxxx xxxx xxxx xxxx */
> + DECODE_CUSTOM (0xffdf0000, 0xe90d0000, STACK_USE_STMDX),
> +
> + /* fall through */
> + DECODE_CUSTOM (0, 0, STACK_USE_NONE),
> + DECODE_END
> + };
> +
> + return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL);
> +}
> +
> +const struct decode_checker t32_stack_checker[NUM_PROBES_T32_ACTIONS] = {
> + [PROBES_T32_LDMSTM] = {.checker = t32_check_stack},
> + [PROBES_T32_LDRDSTRD] = {.checker = t32_check_stack},
> + [PROBES_T32_LDRSTR] = {.checker = t32_check_stack},
> +};
> +
> +/*
> + * See following comments. This insn must be 'push'.
> + */
> +static enum probes_insn __kprobes t16_check_stack(probes_opcode_t insn,
> + struct arch_probes_insn *asi,
> + const struct decode_header *h)
> +{
> + unsigned int reglist = insn & 0x1ff;
> + asi->stack_space = hweight32(reglist) * 4;
> + return INSN_GOOD;
> +}
> +
> +/*
> + * T16 encoding is simple: only the 'push' insn can need extra stack space.
> + * Other insns, like str, can only use r0-r7 as Rn.
> + */
> +const struct decode_checker t16_stack_checker[NUM_PROBES_T16_ACTIONS] = {
> + [PROBES_T16_PUSH] = {.checker = t16_check_stack},
> +};
> diff --git a/arch/arm/kernel/probes-checkers.h b/arch/arm/kernel/probes-checkers.h
> new file mode 100644
> index 0000000..c92671b
> --- /dev/null
> +++ b/arch/arm/kernel/probes-checkers.h
> @@ -0,0 +1,54 @@
> +/*
> + * arch/arm/kernel/probes-checkers-common.c
> + *
> + * Copyright (C) 2014 Huawei Inc.
> + *
> + * 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_CHECKERS_H
> +#define _ARM_KERNEL_PROBES_CHECKERS_H
> +
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include "probes.h"
> +
> +extern probes_check_t checker_stack_use_none;
> +extern probes_check_t checker_stack_use_unknown;
> +#ifdef CONFIG_THUMB2_KERNEL
> +extern probes_check_t checker_stack_use_imm_0xx;
> +#else
> +extern probes_check_t checker_stack_use_imm_x0x;
> +#endif
> +extern probes_check_t checker_stack_use_imm_xxx;
> +extern probes_check_t checker_stack_use_stmdx;
> +
> +enum {
> + STACK_USE_NONE,
> + STACK_USE_UNKNOWN,
> +#ifdef CONFIG_THUMB2_KERNEL
> + STACK_USE_FIXED_0XX,
> + STACK_USE_T32STRD,
> +#else
> + STACK_USE_FIXED_X0X,
> +#endif
> + STACK_USE_FIXED_XXX,
> + STACK_USE_STMDX,
> + NUM_STACK_USE_TYPES
> +};
> +
> +extern const union decode_action stack_check_actions[];
> +
> +#ifndef CONFIG_THUMB2_KERNEL
> +extern const struct decode_checker arm_stack_checker[];
> +#else
> +#endif
> +extern const struct decode_checker t32_stack_checker[];
> +extern const struct decode_checker t16_stack_checker[];
> +#endif
> diff --git a/arch/arm/kernel/probes.c b/arch/arm/kernel/probes.c
> index 6a7d92e..cc68986 100644
> --- a/arch/arm/kernel/probes.c
> +++ b/arch/arm/kernel/probes.c
> @@ -425,6 +425,16 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
> */
> probes_opcode_t origin_insn = insn;
>
> + /*
> + * stack_space is initialized to 0 here. Checker functions
> + * should update is value if they find this is a stack store
> + * instruction: positive value means bytes of stack usage,
> + * negitive value means unable to determine stack usage
> + * statically. For instruction doesn't store to stack, checker
> + * do nothing with it.
> + */
> + asi->stack_space = 0;
> +
> if (emulate)
> insn = prepare_emulated_insn(insn, asi, thumb);
>
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com
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