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ARM: kprobes: collects stack consumption for store instructions

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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@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This commit is contained in:
Wang Nan 2015-01-05 19:29:21 +08:00 committed by Jon Medhurst
parent 83803d97da
commit 6624cf651f
9 changed files with 383 additions and 6 deletions
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1
arch/arm/include/asm/probes.h
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@ -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

10
arch/arm/probes/decode.c
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@ -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);

6
arch/arm/probes/kprobes/Makefile
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@ -1,11 +1,11 @@
obj-$(CONFIG_KPROBES) += core.o actions-common.o
obj-$(CONFIG_KPROBES) += core.o actions-common.o checkers-common.o
obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o
test-kprobes-objs := test-core.o
ifdef CONFIG_THUMB2_KERNEL
obj-$(CONFIG_KPROBES) += actions-thumb.o
obj-$(CONFIG_KPROBES) += actions-thumb.o checkers-thumb.o
test-kprobes-objs += test-thumb.o
else
obj-$(CONFIG_KPROBES) += actions-arm.o
obj-$(CONFIG_KPROBES) += actions-arm.o checkers-arm.o
test-kprobes-objs += test-arm.o
endif

3
arch/arm/probes/kprobes/actions-arm.c
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@ -64,6 +64,7 @@
#include "../decode-arm.h"
#include "core.h"
#include "checkers.h"
#if __LINUX_ARM_ARCH__ >= 6
#define BLX(reg) "blx "reg" \n\t"
@ -340,4 +341,4 @@ 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};

5
arch/arm/probes/kprobes/actions-thumb.c
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@ -15,6 +15,7 @@
#include "../decode-thumb.h"
#include "core.h"
#include "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};

99
arch/arm/probes/kprobes/checkers-arm.c Normal file
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@ -0,0 +1,99 @@
/*
* arch/arm/probes/kprobes/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 "../decode.h"
#include "../decode-arm.h"
#include "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},
};

101
arch/arm/probes/kprobes/checkers-common.c Normal file
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@ -0,0 +1,101 @@
/*
* arch/arm/probes/kprobes/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 "../decode.h"
#include "../decode-arm.h"
#include "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},
};

110
arch/arm/probes/kprobes/checkers-thumb.c Normal file
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@ -0,0 +1,110 @@
/*
* arch/arm/probes/kprobes/checkers-thumb.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 "../decode.h"
#include "../decode-thumb.h"
#include "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},
};

54
arch/arm/probes/kprobes/checkers.h Normal file
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@ -0,0 +1,54 @@
/*
* arch/arm/probes/kprobes/checkers.h
*
* 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 "../decode.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