Re: [PATCH 2/4] ARM: Thumb-2: Make undefined instruction handler support Thumb kernel code

On Mon, 21 Mar 2011, Tixy wrote:

From: Jon Medhurst tixy@yxit.co.uk

Signed-off-by: Jon Medhurst tixy@yxit.co.uk

arch/arm/kernel/traps.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 21ac43f..6468100 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -356,7 +356,12 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) pc = (void __user *)instruction_pointer(regs); if (processor_mode(regs) == SVC_MODE) {

• instr = *(u32 *) pc;
  

+#ifdef CONFIG_THUMB2_KERNEL

• if (thumb_mode(regs))
  

• 	instr = *(u16 *) pc;
  

• else
  

+#endif

• 	instr = *(u32 *) pc;
  

Although I suggested always using a 16-bit instruction for kprobe breakpoint, the above looks to be broken for 32-bit Thumb instructions.

Nicolas