From 602cd2609eee92d338a83e400774e97c60535ba2 Mon Sep 17 00:00:00 2001 From: "David A. Long" Date: Wed, 5 Mar 2014 21:40:12 -0500 Subject: [PATCH] ARM: Add an emulate flag to the kprobes/uprobes instruction decode functions Add an emulate flag into the instruction interpreter, primarily for uprobes support. Signed-off-by: David A. Long Acked-by: Jon Medhurst --- arch/arm/kernel/kprobes.c | 2 +- arch/arm/kernel/kprobes.h | 1 + arch/arm/kernel/probes-arm.c | 4 ++-- arch/arm/kernel/probes-arm.h | 2 +- arch/arm/kernel/probes-thumb.c | 8 ++++---- arch/arm/kernel/probes-thumb.h | 4 ++-- arch/arm/kernel/probes.c | 18 +++++++++++++----- arch/arm/kernel/probes.h | 2 +- 8 files changed, 25 insertions(+), 16 deletions(-) diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 468d4a9..8795f9f 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -89,7 +89,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) p->opcode = insn; p->ainsn.insn = tmp_insn; - switch ((*decode_insn)(insn, &p->ainsn, actions)) { + switch ((*decode_insn)(insn, &p->ainsn, true, actions)) { case INSN_REJECTED: /* not supported */ return -EINVAL; diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index eee8089..d0a24b7 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -35,6 +35,7 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi, typedef enum probes_insn (kprobe_decode_insn_t)(probes_opcode_t, struct arch_specific_insn *, + bool, const union decode_action *); #ifdef CONFIG_THUMB2_KERNEL diff --git a/arch/arm/kernel/probes-arm.c b/arch/arm/kernel/probes-arm.c index 738e5fc5..8e7fde8 100644 --- a/arch/arm/kernel/probes-arm.c +++ b/arch/arm/kernel/probes-arm.c @@ -725,10 +725,10 @@ static void __kprobes arm_singlestep(probes_opcode_t insn, */ enum probes_insn __kprobes arm_probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_action *actions) + bool emulate, const union decode_action *actions) { asi->insn_singlestep = arm_singlestep; asi->insn_check_cc = probes_condition_checks[insn>>28]; return probes_decode_insn(insn, asi, probes_decode_arm_table, false, - actions); + emulate, actions); } diff --git a/arch/arm/kernel/probes-arm.h b/arch/arm/kernel/probes-arm.h index 7a5cce4..ea614dc 100644 --- a/arch/arm/kernel/probes-arm.h +++ b/arch/arm/kernel/probes-arm.h @@ -67,7 +67,7 @@ void __kprobes simulate_mov_ipsp(probes_opcode_t opcode, extern const union decode_item probes_decode_arm_table[]; enum probes_insn arm_probes_decode_insn(probes_opcode_t, - struct arch_specific_insn *, + struct arch_specific_insn *, bool emulate, const union decode_action *actions); #endif diff --git a/arch/arm/kernel/probes-thumb.c b/arch/arm/kernel/probes-thumb.c index eab440f..23e2cbd 100644 --- a/arch/arm/kernel/probes-thumb.c +++ b/arch/arm/kernel/probes-thumb.c @@ -863,20 +863,20 @@ static void __kprobes thumb32_singlestep(probes_opcode_t opcode, enum probes_insn __kprobes thumb16_probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_action *actions) + bool emulate, const union decode_action *actions) { asi->insn_singlestep = thumb16_singlestep; asi->insn_check_cc = thumb_check_cc; return probes_decode_insn(insn, asi, probes_decode_thumb16_table, true, - actions); + emulate, actions); } enum probes_insn __kprobes thumb32_probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_action *actions) + bool emulate, const union decode_action *actions) { asi->insn_singlestep = thumb32_singlestep; asi->insn_check_cc = thumb_check_cc; return probes_decode_insn(insn, asi, probes_decode_thumb32_table, true, - actions); + emulate, actions); } diff --git a/arch/arm/kernel/probes-thumb.h b/arch/arm/kernel/probes-thumb.h index d6f67c1d..65e4250 100644 --- a/arch/arm/kernel/probes-thumb.h +++ b/arch/arm/kernel/probes-thumb.h @@ -89,9 +89,9 @@ extern const union decode_item probes_decode_thumb16_table[]; enum probes_insn __kprobes thumb16_probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_action *actions); + bool emulate, const union decode_action *actions); enum probes_insn __kprobes thumb32_probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_action *actions); + bool emulate, const union decode_action *actions); #endif diff --git a/arch/arm/kernel/probes.c b/arch/arm/kernel/probes.c index b6d9b85..f9dff12 100644 --- a/arch/arm/kernel/probes.c +++ b/arch/arm/kernel/probes.c @@ -257,7 +257,7 @@ set_emulated_insn(probes_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(probes_opcode_t *pinsn, u32 regs) +static bool __kprobes decode_regs(probes_opcode_t *pinsn, u32 regs, bool modify) { probes_opcode_t insn = *pinsn; probes_opcode_t mask = 0xf; /* Start at least significant nibble */ @@ -323,7 +323,9 @@ static bool __kprobes decode_regs(probes_opcode_t *pinsn, u32 regs) insn |= new_bits & mask; } - *pinsn = insn; + if (modify) + *pinsn = insn; + return true; reject: @@ -385,13 +387,14 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = { int __kprobes probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, const union decode_item *table, bool thumb, - const union decode_action *actions) + bool emulate, const union decode_action *actions) { 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 (emulate) + insn = prepare_emulated_insn(insn, asi, thumb); for (;; h = next) { enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; @@ -406,7 +409,7 @@ probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, if (!matched && (insn & h->mask.bits) != h->value.bits) continue; - if (!decode_regs(&insn, regs)) + if (!decode_regs(&insn, regs, emulate)) return INSN_REJECTED; switch (type) { @@ -430,6 +433,11 @@ probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, case DECODE_TYPE_EMULATE: { struct decode_emulate *d = (struct decode_emulate *)h; + + if (!emulate) + return actions[d->handler.action].decoder(insn, + asi, h); + asi->insn_handler = actions[d->handler.action].handler; set_emulated_insn(insn, asi, thumb); return INSN_GOOD; diff --git a/arch/arm/kernel/probes.h b/arch/arm/kernel/probes.h index 0c72e544..33cc30c 100644 --- a/arch/arm/kernel/probes.h +++ b/arch/arm/kernel/probes.h @@ -401,7 +401,7 @@ probes_insn_handler_t probes_emulate_none; int __kprobes probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi, - const union decode_item *table, bool thumb, + const union decode_item *table, bool thumb, bool emulate, const union decode_action *actions); #endif -- 2.7.4