| Message ID | 1416645613-38904-3-git-send-email-wangnan0@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
(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@huawei.com> > Signed-off-by: Jon Medhurst <tixy@linaro.org> > Reviewed-by: Jon Medhurst <tixy@linaro.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@hitachi.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); > >
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);