diff mbox

[2/9] ARM: kprobes: fix instruction fetch order with <asm/opcodes.h>

Message ID 1383935832-20865-3-git-send-email-ben.dooks@codethink.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Ben Dooks Nov. 8, 2013, 6:37 p.m. UTC
If we are running BE8, the data and instruction endian-ness do not
match, so use <asm/opcodes.h> to correctly translate memory accesses
into ARM instructions.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>y
---
 arch/arm/kernel/kprobes-common.c | 14 ++++++++------
 arch/arm/kernel/kprobes.c        |  9 +++++----
 2 files changed, 13 insertions(+), 10 deletions(-)

Comments

Taras Kondratiuk Nov. 29, 2013, 1:01 p.m. UTC | #1
On 8 November 2013 20:37, Ben Dooks <ben.dooks@codethink.co.uk> wrote:
> If we are running BE8, the data and instruction endian-ness do not
> match, so use <asm/opcodes.h> to correctly translate memory accesses
> into ARM instructions.
>
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>y
> ---
>  arch/arm/kernel/kprobes-common.c | 14 ++++++++------
>  arch/arm/kernel/kprobes.c        |  9 +++++----
>  2 files changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c
> index 18a7628..4954e0f 100644
> --- a/arch/arm/kernel/kprobes-common.c
> +++ b/arch/arm/kernel/kprobes-common.c
> @@ -14,6 +14,7 @@
>  #include <linux/kernel.h>
>  #include <linux/kprobes.h>
>  #include <asm/system_info.h>
> +#include <asm/opcodes.h>
>
>  #include "kprobes.h"
>
> @@ -305,7 +306,8 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
>
>         if (handler) {
>                 /* We can emulate the instruction in (possibly) modified form */
> -               asi->insn[0] = (insn & 0xfff00000) | (rn << 16) | reglist;
> +               asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
> +                                                  (rn << 16) | reglist);
>                 asi->insn_handler = handler;
>                 return INSN_GOOD;
>         }
> @@ -338,9 +340,9 @@ prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
>                 thumb_insn[2] = 0x4770; /* Thumb bx lr */

should be
thumb_insn[1] = __opcode_to_mem_thumb16(0x4770);
thumb_insn[2] = __opcode_to_mem_thumb16(0x4770);

>                 return insn;
>         }
> -       asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
> +       asi->insn[1] = __opcode_to_mem_arm(0xe12fff1e); /* ARM bx lr */
>  #else
> -       asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
> +       asi->insn[1] = __opcode_to_mem_arm(0xe1a0f00e); /* mov pc, lr */
>  #endif
>         /* Make an ARM instruction unconditional */
>         if (insn < 0xe0000000)
Ben Dooks Nov. 29, 2013, 5:55 p.m. UTC | #2
On 29/11/13 13:01, Taras Kondratiuk wrote:
> On 8 November 2013 20:37, Ben Dooks <ben.dooks@codethink.co.uk> wrote:
>> If we are running BE8, the data and instruction endian-ness do not
>> match, so use <asm/opcodes.h> to correctly translate memory accesses
>> into ARM instructions.
>>
>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>y
>> ---
>>   arch/arm/kernel/kprobes-common.c | 14 ++++++++------
>>   arch/arm/kernel/kprobes.c        |  9 +++++----
>>   2 files changed, 13 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c
>> index 18a7628..4954e0f 100644
>> --- a/arch/arm/kernel/kprobes-common.c
>> +++ b/arch/arm/kernel/kprobes-common.c
>> @@ -14,6 +14,7 @@
>>   #include <linux/kernel.h>
>>   #include <linux/kprobes.h>
>>   #include <asm/system_info.h>
>> +#include <asm/opcodes.h>
>>
>>   #include "kprobes.h"
>>
>> @@ -305,7 +306,8 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
>>
>>          if (handler) {
>>                  /* We can emulate the instruction in (possibly) modified form */
>> -               asi->insn[0] = (insn & 0xfff00000) | (rn << 16) | reglist;
>> +               asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
>> +                                                  (rn << 16) | reglist);
>>                  asi->insn_handler = handler;
>>                  return INSN_GOOD;
>>          }
>> @@ -338,9 +340,9 @@ prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
>>                  thumb_insn[2] = 0x4770; /* Thumb bx lr */
>
> should be
> thumb_insn[1] = __opcode_to_mem_thumb16(0x4770);
> thumb_insn[2] = __opcode_to_mem_thumb16(0x4770);
>
>>                  return insn;
>>          }
>> -       asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
>> +       asi->insn[1] = __opcode_to_mem_arm(0xe12fff1e); /* ARM bx lr */
>>   #else
>> -       asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
>> +       asi->insn[1] = __opcode_to_mem_arm(0xe1a0f00e); /* mov pc, lr */
>>   #endif
>>          /* Make an ARM instruction unconditional */
>>          if (insn < 0xe0000000)
>

Thanks, will re-do these patches.
diff mbox

Patch

diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c
index 18a7628..4954e0f 100644
--- a/arch/arm/kernel/kprobes-common.c
+++ b/arch/arm/kernel/kprobes-common.c
@@ -14,6 +14,7 @@ 
 #include <linux/kernel.h>
 #include <linux/kprobes.h>
 #include <asm/system_info.h>
+#include <asm/opcodes.h>
 
 #include "kprobes.h"
 
@@ -305,7 +306,8 @@  kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 
 	if (handler) {
 		/* We can emulate the instruction in (possibly) modified form */
-		asi->insn[0] = (insn & 0xfff00000) | (rn << 16) | reglist;
+		asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
+						   (rn << 16) | reglist);
 		asi->insn_handler = handler;
 		return INSN_GOOD;
 	}
@@ -338,9 +340,9 @@  prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
 		thumb_insn[2] = 0x4770; /* Thumb bx lr */
 		return insn;
 	}
-	asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
+	asi->insn[1] = __opcode_to_mem_arm(0xe12fff1e); /* ARM bx lr */
 #else
-	asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
+	asi->insn[1] = __opcode_to_mem_arm(0xe1a0f00e); /* mov pc, lr */
 #endif
 	/* Make an ARM instruction unconditional */
 	if (insn < 0xe0000000)
@@ -360,12 +362,12 @@  set_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
 	if (thumb) {
 		u16 *ip = (u16 *)asi->insn;
 		if (is_wide_instruction(insn))
-			*ip++ = insn >> 16;
-		*ip++ = insn;
+			*ip++ = __opcode_to_mem_thumb16(insn >> 16);
+		*ip++ = __opcode_to_mem_thumb16(insn);
 		return;
 	}
 #endif
-	asi->insn[0] = insn;
+	asi->insn[0] = __opcode_to_mem_arm(insn);
 }
 
 /*
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 170e9f3..1c6ece5 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -26,6 +26,7 @@ 
 #include <linux/stop_machine.h>
 #include <linux/stringify.h>
 #include <asm/traps.h>
+#include <asm/opcodes.h>
 #include <asm/cacheflush.h>
 
 #include "kprobes.h"
@@ -62,10 +63,10 @@  int __kprobes arch_prepare_kprobe(struct kprobe *p)
 #ifdef CONFIG_THUMB2_KERNEL
 	thumb = true;
 	addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */
-	insn = ((u16 *)addr)[0];
+	insn = __mem_to_opcode_thumb16(((u16 *)addr)[0]);
 	if (is_wide_instruction(insn)) {
-		insn <<= 16;
-		insn |= ((u16 *)addr)[1];
+		u16 inst2 = __mem_to_opcode_thumb16(((u16 *)addr)[1]);
+		insn = __opcode_thumb32_compose(insn, inst2);
 		decode_insn = thumb32_kprobe_decode_insn;
 	} else
 		decode_insn = thumb16_kprobe_decode_insn;
@@ -73,7 +74,7 @@  int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	thumb = false;
 	if (addr & 0x3)
 		return -EINVAL;
-	insn = *p->addr;
+	insn = __mem_to_opcode_arm(*p->addr);
 	decode_insn = arm_kprobe_decode_insn;
 #endif