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

[Taras Kondratiuk]

On 8 November 2013 20:37, Ben Dooks <ben.dooks at 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 at 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)

-- 
Regards,
Taras Kondratiuk