[8/9] ARM: support uprobe handling

Message ID	1350242593-17761-8-git-send-email-rabin@rab.in (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Rabin Vincent <rabin@rab.in> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 8/9] ARM: support uprobe handling Date: Sun, 14 Oct 2012 21:23:12 +0200 Message-Id: <1350242593-17761-8-git-send-email-rabin@rab.in> In-Reply-To: <1350242593-17761-1-git-send-email-rabin@rab.in> References: <1350242593-17761-1-git-send-email-rabin@rab.in> summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.217.177 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rabin.vincent[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature Cc: Peter Zijlstra <peterz@infradead.org>, Rabin Vincent <rabin@rab.in>, Jon Medhurst <tixy@yxit.co.uk>, Srikar Dronamraju <srikar@linux.vnet.ibm.com>, oleg@redhat.com Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h index f82ec22..53b1a80 100644 --- a/arch/arm/include/asm/kprobes.h +++ b/arch/arm/include/asm/kprobes.h @@ -27,22 +27,7 @@ #define flush_insn_slot(p) do { } while (0) #define kretprobe_blacklist_size 0 -typedef u32 kprobe_opcode_t; - -struct kprobe; -typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *); -typedef unsigned long (kprobe_check_cc)(unsigned long); -typedef void (kprobe_insn_singlestep_t)(struct kprobe *, struct pt_regs *); -typedef void (kprobe_insn_fn_t)(void); - -/* Architecture specific copy of original instruction. */ -struct arch_specific_insn { - kprobe_opcode_t *insn; - kprobe_insn_handler_t *insn_handler; - kprobe_check_cc *insn_check_cc; - kprobe_insn_singlestep_t *insn_singlestep; - kprobe_insn_fn_t *insn_fn; -}; +#include <asm/probes.h> struct prev_kprobe { struct kprobe *kp; diff --git a/arch/arm/include/asm/probes.h b/arch/arm/include/asm/probes.h new file mode 100644 index 0000000..df46994 --- /dev/null +++ b/arch/arm/include/asm/probes.h @@ -0,0 +1,23 @@ +#ifndef _ASM_PROBES_H +#define _ASM_PROBES_H + +#ifdef CONFIG_KPROBES +typedef u32 kprobe_opcode_t; + +struct kprobe; +typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *); +typedef unsigned long (kprobe_check_cc)(unsigned long); +typedef void (kprobe_insn_singlestep_t)(struct kprobe *, struct pt_regs *); +typedef void (kprobe_insn_fn_t)(void); + +/* Architecture specific copy of original instruction. */ +struct arch_specific_insn { + kprobe_opcode_t *insn; + kprobe_insn_handler_t *insn_handler; + kprobe_check_cc *insn_check_cc; + kprobe_insn_singlestep_t *insn_singlestep; + kprobe_insn_fn_t *insn_fn; +}; +#endif + +#endif diff --git a/arch/arm/kernel/kprobes-arm.c b/arch/arm/kernel/kprobes-arm.c index 8a30c89..d9cf0e2 100644 --- a/arch/arm/kernel/kprobes-arm.c +++ b/arch/arm/kernel/kprobes-arm.c @@ -62,6 +62,7 @@ #include <linux/kprobes.h> #include <linux/module.h> +#include "uprobes.h" #include "kprobes.h" #define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit))))) @@ -545,31 +546,37 @@ static const union decode_item arm_cccc_000x_____1xx1_table[] = { /* LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx */ /* STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e5000d0, 0x000000d0, emulate_ldrdstrd, REGS(NOPCWB, NOPCX, 0, 0, NOPC)), /* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */ /* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e5000d0, 0x004000d0, emulate_ldrdstrd, REGS(NOPCWB, NOPCX, 0, 0, 0)), /* STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e5000f0, 0x000000b0, emulate_str, REGS(NOPCWB, NOPC, 0, 0, NOPC)), /* LDRH (register) cccc 000x x0x1 xxxx xxxx xxxx 1011 xxxx */ /* LDRSB (register) cccc 000x x0x1 xxxx xxxx xxxx 1101 xxxx */ /* LDRSH (register) cccc 000x x0x1 xxxx xxxx xxxx 1111 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e500090, 0x00100090, emulate_ldr, REGS(NOPCWB, NOPC, 0, 0, NOPC)), /* STRH (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1011 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e5000f0, 0x004000b0, emulate_str, REGS(NOPCWB, NOPC, 0, 0, 0)), /* LDRH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1011 xxxx */ /* LDRSB (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1101 xxxx */ /* LDRSH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1111 xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e500090, 0x00500090, emulate_ldr, REGS(NOPCWB, NOPC, 0, 0, 0)), @@ -589,11 +596,13 @@ static const union decode_item arm_cccc_000x_table[] = { /* TEQ (register) cccc 0001 0011 xxxx xxxx xxxx xxx0 xxxx */ /* CMP (register) cccc 0001 0101 xxxx xxxx xxxx xxx0 xxxx */ /* CMN (register) cccc 0001 0111 xxxx xxxx xxxx xxx0 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0f900010, 0x01100000, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, 0, 0, 0, ANY)), /* MOV (register) cccc 0001 101x xxxx xxxx xxxx xxx0 xxxx */ /* MVN (register) cccc 0001 111x xxxx xxxx xxxx xxx0 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0fa00010, 0x01a00000, emulate_rd12rn16rm0rs8_rwflags, REGS(0, ANY, 0, 0, ANY)), @@ -607,6 +616,7 @@ static const union decode_item arm_cccc_000x_table[] = { /* RSC (register) cccc 0000 111x xxxx xxxx xxxx xxx0 xxxx */ /* ORR (register) cccc 0001 100x xxxx xxxx xxxx xxx0 xxxx */ /* BIC (register) cccc 0001 110x xxxx xxxx xxxx xxx0 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0e000010, 0x00000000, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, ANY, 0, 0, ANY)), @@ -614,11 +624,13 @@ static const union decode_item arm_cccc_000x_table[] = { /* TEQ (reg-shift reg) cccc 0001 0011 xxxx xxxx xxxx 0xx1 xxxx */ /* CMP (reg-shift reg) cccc 0001 0101 xxxx xxxx xxxx 0xx1 xxxx */ /* CMN (reg-shift reg) cccc 0001 0111 xxxx xxxx xxxx 0xx1 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0f900090, 0x01100010, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, 0, NOPC, 0, ANY)), /* MOV (reg-shift reg) cccc 0001 101x xxxx xxxx xxxx 0xx1 xxxx */ /* MVN (reg-shift reg) cccc 0001 111x xxxx xxxx xxxx 0xx1 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0fa00090, 0x01a00010, emulate_rd12rn16rm0rs8_rwflags, REGS(0, ANY, NOPC, 0, ANY)), @@ -632,6 +644,7 @@ static const union decode_item arm_cccc_000x_table[] = { /* RSC (reg-shift reg) cccc 0000 111x xxxx xxxx xxxx 0xx1 xxxx */ /* ORR (reg-shift reg) cccc 0001 100x xxxx xxxx xxxx 0xx1 xxxx */ /* BIC (reg-shift reg) cccc 0001 110x xxxx xxxx xxxx 0xx1 xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0e000090, 0x00000010, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, ANY, NOPC, 0, ANY)), @@ -666,11 +679,13 @@ static const union decode_item arm_cccc_001x_table[] = { /* TEQ (immediate) cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx */ /* CMP (immediate) cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx */ /* CMN (immediate) cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0f900000, 0x03100000, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, 0, 0, 0, 0)), /* MOV (immediate) cccc 0011 101x xxxx xxxx xxxx xxxx xxxx */ /* MVN (immediate) cccc 0011 111x xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0fa00000, 0x03a00000, emulate_rd12rn16rm0rs8_rwflags, REGS(0, ANY, 0, 0, 0)), @@ -684,6 +699,7 @@ static const union decode_item arm_cccc_001x_table[] = { /* RSC (immediate) cccc 0010 111x xxxx xxxx xxxx xxxx xxxx */ /* ORR (immediate) cccc 0011 100x xxxx xxxx xxxx xxxx xxxx */ /* BIC (immediate) cccc 0011 110x xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_rd12rn16rm0rs8_rwflags) DECODE_EMULATEX (0x0e000000, 0x02000000, emulate_rd12rn16rm0rs8_rwflags, REGS(ANY, ANY, 0, 0, 0)), @@ -850,21 +866,25 @@ static const union decode_item arm_cccc_01xx_table[] = { /* STR (immediate) cccc 010x x0x0 xxxx xxxx xxxx xxxx xxxx */ /* STRB (immediate) cccc 010x x1x0 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e100000, 0x04000000, emulate_str, REGS(NOPCWB, ANY, 0, 0, 0)), /* LDR (immediate) cccc 010x x0x1 xxxx xxxx xxxx xxxx xxxx */ /* LDRB (immediate) cccc 010x x1x1 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_ldr) DECODE_EMULATEX (0x0e100000, 0x04100000, emulate_ldr, REGS(NOPCWB, ANY, 0, 0, 0)), /* STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx */ /* STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_pc_ro) DECODE_EMULATEX (0x0e100000, 0x06000000, emulate_str, REGS(NOPCWB, ANY, 0, 0, NOPC)), /* LDR (register) cccc 011x x0x1 xxxx xxxx xxxx xxxx xxxx */ /* LDRB (register) cccc 011x x1x1 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (decode_ldr) DECODE_EMULATEX (0x0e100000, 0x06100000, emulate_ldr, REGS(NOPCWB, ANY, 0, 0, NOPC)), @@ -876,6 +896,7 @@ static const union decode_item arm_cccc_100x_table[] = { /* LDM cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */ /* STM cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */ + UDECODE_NEXT (uprobe_decode_ldmstm) DECODE_CUSTOM (0x0e400000, 0x08000000, kprobe_decode_ldmstm), /* STM (user registers) cccc 100x x1x0 xxxx xxxx xxxx xxxx xxxx */ @@ -997,9 +1018,11 @@ static void __kprobes arm_singlestep(struct kprobe *p, struct pt_regs *regs) * should also be very rare. */ enum kprobe_insn __kprobes -arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) +arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, + bool uprobe) { asi->insn_singlestep = arm_singlestep; asi->insn_check_cc = kprobe_condition_checks[insn>>28]; - return kprobe_decode_insn(insn, asi, kprobe_decode_arm_table, false); + return kprobe_decode_insn(insn, asi, kprobe_decode_arm_table, false, + uprobe); } diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c index 18a7628..f811bfb 100644 --- a/arch/arm/kernel/kprobes-common.c +++ b/arch/arm/kernel/kprobes-common.c @@ -277,7 +277,8 @@ emulate_ldm_r3_15(struct kprobe *p, struct pt_regs *regs) } enum kprobe_insn __kprobes -kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi) +kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d) { kprobe_insn_handler_t *handler = 0; unsigned reglist = insn & 0xffff; @@ -389,7 +390,7 @@ set_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, * non-zero value, the corresponding nibble in pinsn is validated and modified * according to the type. */ -static bool __kprobes decode_regs(kprobe_opcode_t* pinsn, u32 regs) +static bool __kprobes decode_regs(kprobe_opcode_t *pinsn, u32 regs, bool modify) { kprobe_opcode_t insn = *pinsn; kprobe_opcode_t mask = 0xf; /* Start at least significant nibble */ @@ -450,12 +451,16 @@ static bool __kprobes decode_regs(kprobe_opcode_t* pinsn, u32 regs) break; } - /* Replace value of nibble with new register number... */ - insn &= ~mask; - insn |= new_bits & mask; + if (modify) { + /* Replace value of nibble with new register number */ + insn &= ~mask; + insn |= new_bits & mask; + } } - *pinsn = insn; + if (modify) + *pinsn = insn; + return true; reject: @@ -468,7 +473,8 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = { [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate), [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate), [DECODE_TYPE_OR] = sizeof(struct decode_or), - [DECODE_TYPE_REJECT] = sizeof(struct decode_reject) + [DECODE_TYPE_REJECT] = sizeof(struct decode_reject), + [UDECODE_TYPE_NEXT] = sizeof(struct decode_header) }; /* @@ -516,13 +522,17 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = { */ int __kprobes kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, - const union decode_item *table, bool thumb) + const union decode_item *table, bool thumb, + bool uprobe) { + enum kprobe_insn (*decoder)(kprobe_opcode_t, + struct arch_specific_insn *, void *d) = NULL; const struct decode_header *h = (struct decode_header *)table; const struct decode_header *next; bool matched = false; - insn = prepare_emulated_insn(insn, asi, thumb); + if (!uprobe) + insn = prepare_emulated_insn(insn, asi, thumb); for (;; h = next) { enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; @@ -534,13 +544,24 @@ kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, next = (struct decode_header *) ((uintptr_t)h + decode_struct_sizes[type]); - if (!matched && (insn & h->mask.bits) != h->value.bits) + if (!uprobe && type == UDECODE_TYPE_NEXT) continue; - if (!decode_regs(&insn, regs)) - return INSN_REJECTED; + if (type != UDECODE_TYPE_NEXT) { + if (!matched && + (insn & h->mask.bits) != h->value.bits) { + decoder = NULL; + continue; + } + + if (!decode_regs(&insn, regs, !uprobe)) + return INSN_REJECTED; + } switch (type) { + case UDECODE_TYPE_NEXT: + decoder = h->mask.decoder; + break; case DECODE_TYPE_TABLE: { struct decode_table *d = (struct decode_table *)h; @@ -550,7 +571,11 @@ kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, case DECODE_TYPE_CUSTOM: { struct decode_custom *d = (struct decode_custom *)h; - return (*d->decoder.decoder)(insn, asi); + + if (decoder) + return decoder(insn, asi, d); + + return (*d->decoder.decoder)(insn, asi, d); } case DECODE_TYPE_SIMULATE: { @@ -561,8 +586,14 @@ kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, case DECODE_TYPE_EMULATE: { struct decode_emulate *d = (struct decode_emulate *)h; - asi->insn_handler = d->handler.handler; - set_emulated_insn(insn, asi, thumb); + + if (decoder) + return decoder(insn, asi, d); + + if (!uprobe) { + asi->insn_handler = d->handler.handler; + set_emulated_insn(insn, asi, thumb); + } return INSN_GOOD; } @@ -574,5 +605,5 @@ kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, default: return INSN_REJECTED; } - } } +} diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c index 1862d8f..a2d4213 100644 --- a/arch/arm/kernel/kprobes-test.c +++ b/arch/arm/kernel/kprobes-test.c @@ -630,7 +630,8 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = { [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate), [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate), [DECODE_TYPE_OR] = sizeof(struct decode_or), - [DECODE_TYPE_REJECT] = sizeof(struct decode_reject) + [DECODE_TYPE_REJECT] = sizeof(struct decode_reject), + [UDECODE_TYPE_NEXT] = sizeof(struct decode_header) }; static int table_iter(const union decode_item *table, @@ -646,9 +647,11 @@ static int table_iter(const union decode_item *table, if (type == DECODE_TYPE_END) return 0; - result = fn(h, args); - if (result) - return result; + if (type != UDECODE_TYPE_NEXT) { + result = fn(h, args); + if (result) + return result; + } h = (struct decode_header *) ((uintptr_t)h + decode_struct_sizes[type]); @@ -918,6 +921,7 @@ static void coverage_add(kprobe_opcode_t insn) break; case DECODE_TYPE_REJECT: + case UDECODE_TYPE_NEXT: default: return; } diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index 6123daf..761aa55 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -83,7 +83,8 @@ t32_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t32_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t32_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d) { int cc = (insn >> 22) & 0xf; asi->insn_check_cc = kprobe_condition_checks[cc]; @@ -158,9 +159,10 @@ t32_simulate_ldr_literal(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d) { - enum kprobe_insn ret = kprobe_decode_ldmstm(insn, asi); + enum kprobe_insn ret = kprobe_decode_ldmstm(insn, asi, d); /* Fixup modified instruction to have halfwords in correct order...*/ insn = asi->insn[0]; @@ -1046,7 +1048,7 @@ t16_singlestep_it(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t16_decode_it(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t16_decode_it(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) { asi->insn_singlestep = t16_singlestep_it; return INSN_GOOD_NO_SLOT; @@ -1063,7 +1065,8 @@ t16_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t16_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t16_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d) { int cc = (insn >> 8) & 0xf; asi->insn_check_cc = kprobe_condition_checks[cc]; @@ -1149,7 +1152,7 @@ t16_emulate_hiregs(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) { insn &= ~0x00ff; insn |= 0x001; /* Set Rdn = R1 and Rm = R0 */ @@ -1175,7 +1178,7 @@ t16_emulate_push(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) { /* * To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}" @@ -1225,7 +1228,7 @@ t16_emulate_pop_pc(struct kprobe *p, struct pt_regs *regs) } static enum kprobe_insn __kprobes -t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi) +t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) { /* * To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}" @@ -1453,17 +1456,21 @@ static void __kprobes thumb32_singlestep(struct kprobe *p, struct pt_regs *regs) } enum kprobe_insn __kprobes -thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) +thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, + bool uprobes) { asi->insn_singlestep = thumb16_singlestep; asi->insn_check_cc = thumb_check_cc; - return kprobe_decode_insn(insn, asi, kprobe_decode_thumb16_table, true); + return kprobe_decode_insn(insn, asi, kprobe_decode_thumb16_table, true, + uprobes); } enum kprobe_insn __kprobes -thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) +thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, + bool uprobes) { asi->insn_singlestep = thumb32_singlestep; asi->insn_check_cc = thumb_check_cc; - return kprobe_decode_insn(insn, asi, kprobe_decode_thumb32_table, true); + return kprobe_decode_insn(insn, asi, kprobe_decode_thumb32_table, true, + uprobes); } diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 4dd41fc..1b2a324 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -80,7 +80,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) p->opcode = insn; p->ainsn.insn = tmp_insn; - switch ((*decode_insn)(insn, &p->ainsn)) { + switch ((*decode_insn)(insn, &p->ainsn, false)) { case INSN_REJECTED: /* not supported */ return -EINVAL; diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index 38945f7..442a161 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -35,20 +35,19 @@ enum kprobe_insn { }; typedef enum kprobe_insn (kprobe_decode_insn_t)(kprobe_opcode_t, - struct arch_specific_insn *); - -#ifdef CONFIG_THUMB2_KERNEL + struct arch_specific_insn *, + bool uprobes); enum kprobe_insn thumb16_kprobe_decode_insn(kprobe_opcode_t, - struct arch_specific_insn *); + struct arch_specific_insn *, + bool uprobes); enum kprobe_insn thumb32_kprobe_decode_insn(kprobe_opcode_t, - struct arch_specific_insn *); - -#else /* !CONFIG_THUMB2_KERNEL */ + struct arch_specific_insn *, + bool uprobes); enum kprobe_insn arm_kprobe_decode_insn(kprobe_opcode_t, - struct arch_specific_insn *); -#endif + struct arch_specific_insn *, + bool uprobes); void __init arm_kprobe_decode_init(void); @@ -165,7 +164,8 @@ void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs); void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs); enum kprobe_insn __kprobes -kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi); +kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d); /* * Test if load/store instructions writeback the address register. @@ -292,6 +292,7 @@ enum decode_type { DECODE_TYPE_EMULATE, DECODE_TYPE_OR, DECODE_TYPE_REJECT, + UDECODE_TYPE_NEXT, NUM_DECODE_TYPES /* Must be last enum */ }; @@ -331,7 +332,9 @@ union decode_item { u32 bits; const union decode_item *table; kprobe_insn_handler_t *handler; - kprobe_decode_insn_t *decoder; + enum kprobe_insn (*decoder)(kprobe_opcode_t, + struct arch_specific_insn *, + void *d); }; @@ -396,6 +399,14 @@ struct decode_emulate { #define DECODE_EMULATE(_mask, _value, _handler) \ DECODE_EMULATEX(_mask, _value, _handler, 0) +#ifdef CONFIG_UPROBES +#define UDECODE_NEXT(_decoder) \ + {.bits = UDECODE_TYPE_NEXT }, \ + {.decoder = _decoder}, \ + {.bits = 0 }, +#else +#define UDECODE_NEXT(_decoder) +#endif struct decode_or { struct decode_header header; @@ -422,7 +433,8 @@ extern const union decode_item kprobe_decode_arm_table[]; int kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi, - const union decode_item *table, bool thumb16); + const union decode_item *table, bool thumb16, + bool uprobe); #endif /* _ARM_KERNEL_KPROBES_H */ diff --git a/arch/arm/kernel/uprobes-arm.c b/arch/arm/kernel/uprobes-arm.c new file mode 100644 index 0000000..8d7de10 --- /dev/null +++ b/arch/arm/kernel/uprobes-arm.c @@ -0,0 +1,178 @@ +#include <linux/kernel.h> +#include <linux/kprobes.h> +#include <linux/uprobes.h> +#include <linux/module.h> + +#include "uprobes.h" +#include "kprobes.h" + +static int uprobes_substitute_pc(kprobe_opcode_t *pinsn, u32 oregs) +{ + kprobe_opcode_t insn = *pinsn; + kprobe_opcode_t temp; + kprobe_opcode_t mask; + int freereg; + u32 free = 0xffff; + u32 regs; + + for (regs = oregs; regs; regs >>= 4, insn >>= 4) { + if ((regs & 0xf) == REG_TYPE_NONE) + continue; + + free &= ~(1 << (insn & 0xf)); + } + + /* No PC, no problem */ + if (free & (1 << 15)) + return 15; + + if (!free) + return -1; + + /* + * fls instead of ffs ensures that for "ldrd r0, r1, [pc]" we would + * pick LR instead of R1. + */ + freereg = free = fls(free) - 1; + + temp = *pinsn; + insn = *pinsn; + regs = oregs; + mask = 0xf; + + for (; regs; regs >>= 4, mask <<= 4, free <<= 4, temp >>= 4) { + if ((regs & 0xf) == REG_TYPE_NONE) + continue; + + if ((temp & 0xf) != 15) + continue; + + insn &= ~mask; + insn |= free & mask; + } + + *pinsn = insn; + return freereg; +} + +static void uprobe_set_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + autask->backup = regs->uregs[pcreg]; + regs->uregs[pcreg] = regs->ARM_pc + 8; +} + +static void uprobe_unset_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + /* PC will be taken care of by common code */ + regs->uregs[auprobe->pcreg] = autask->backup; +} + +static void uprobe_aluwrite_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + alu_write_pc(regs->uregs[pcreg], regs); + regs->uregs[pcreg] = autask->backup; +} + +static void uprobe_write_pc(struct arch_uprobe *auprobe, + struct arch_uprobe_task *autask, + struct pt_regs *regs) +{ + u32 pcreg = auprobe->pcreg; + + load_write_pc(regs->uregs[pcreg], regs); + regs->uregs[pcreg] = autask->backup; +} + +enum kprobe_insn +decode_pc_ro(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, asi); + struct decode_emulate *decode = d; + u32 regs = decode->header.type_regs.bits >> DECODE_TYPE_BITS; + int reg; + + reg = uprobes_substitute_pc(&auprobe->modinsn, regs); + if (reg == 15) + return INSN_GOOD; + + if (reg == -1) + return INSN_REJECTED; + + auprobe->pcreg = reg; + auprobe->prehandler = uprobe_set_pc; + auprobe->posthandler = uprobe_unset_pc; + + return INSN_GOOD; +} + +enum kprobe_insn +decode_wb_pc(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d, bool alu) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, asi); + enum kprobe_insn ret = decode_pc_ro(insn, asi, d); + + if (((insn >> 12) & 0xf) == 15) + auprobe->posthandler = alu ? uprobe_aluwrite_pc + : uprobe_write_pc; + + return ret; +} + +enum kprobe_insn +decode_rd12rn16rm0rs8_rwflags(kprobe_opcode_t insn, + struct arch_specific_insn *asi, void *d) +{ + return decode_wb_pc(insn, asi, d, true); +} + +enum kprobe_insn +decode_ldr(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d) +{ + return decode_wb_pc(insn, asi, d, false); +} + +enum kprobe_insn +uprobe_decode_ldmstm(kprobe_opcode_t insn, + struct arch_specific_insn *asi, void *d) +{ + struct arch_uprobe *auprobe = container_of(asi, struct arch_uprobe, + asi); + unsigned reglist = insn & 0xffff; + int rn = (insn >> 16) & 0xf; + int lbit = insn & (1 << 20); + unsigned used = reglist | (1 << rn); + + if (rn == 15) + return INSN_REJECTED; + + if (!(used & (1 << 15))) + return INSN_GOOD; + + if (used & (1 << 14)) + return INSN_REJECTED; + + /* Use LR instead of PC */ + insn ^= 0xc000; + + auprobe->pcreg = 14; + auprobe->modinsn = insn; + + auprobe->prehandler = uprobe_set_pc; + if (lbit) + auprobe->posthandler = uprobe_write_pc; + else + auprobe->posthandler = uprobe_unset_pc; + + return INSN_GOOD; +} diff --git a/arch/arm/kernel/uprobes.h b/arch/arm/kernel/uprobes.h new file mode 100644 index 0000000..a1a4897 --- /dev/null +++ b/arch/arm/kernel/uprobes.h @@ -0,0 +1,23 @@ +#ifndef __ARM_KERNEL_UPROBES_H +#define __ARM_KERNEL_UPROBES_H + +enum kprobe_insn uprobe_decode_ldmstm(kprobe_opcode_t insn, + struct arch_specific_insn *asi, + void *d); + +enum kprobe_insn decode_ldr(kprobe_opcode_t insn, + struct arch_specific_insn *asi, + void *d); + +enum kprobe_insn +decode_rd12rn16rm0rs8_rwflags(kprobe_opcode_t insn, + struct arch_specific_insn *asi, void *d); + +enum kprobe_insn +decode_wb_pc(kprobe_opcode_t insn, struct arch_specific_insn *asi, + void *d, bool alu); + +enum kprobe_insn +decode_pc_ro(kprobe_opcode_t insn, struct arch_specific_insn *asi, void *d); + +#endif

[8/9] ARM: support uprobe handling

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