[PATCH v7 13/15] ARM: Add an emulate flag to the kprobes/uprobes instruction decode functions
From: David Long
Date: Fri Mar 07 2014 - 15:12:01 EST
From: "David A. Long" <dave.long@xxxxxxxxxx>
Add an emulate flag into the instruction interpreter, primarily for uprobes
support.
Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>
Acked-by: Jon Medhurst <tixy@xxxxxxxxxx>
---
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 738e5fc..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 0c72e54..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
--
1.8.1.2
--
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