[PATCH 19/51] ARM: kprobes: Infrastructure for table driven decoding of CPU instructions

[Nicolas Pitre]

On Sat, 9 Jul 2011, Tixy wrote:

> +/*
> + * Prepare an instruction slot to receive an instruction for emulating.
> + * This is done by placing a subroutine return after the location where the
> + * instruction will be placed. We also modify ARM instructions to be
> + * unconditional as the condition code will already be checked before any
> + * emulation handler is called.
> + */
> +static kprobe_opcode_t __kprobes
> +prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
> +								bool thumb)
> +{
> +#ifdef CONFIG_THUMB2_KERNEL
> +	if (thumb) {
> +		u16* thumb_insn = (u16 *)asi->insn;

Ninor style nit: we usually put the * against the variable rather than 
the type.  Here's why:

	u16* a, b, c;

vs

	u16 *a, b, c;

The first case is likely to cause confusion.

> +		thumb_insn[1] = 0x4770; /* Thumb bx lr */
> +		thumb_insn[2] = 0x4770; /* Thumb bx lr */
> +		return insn;
> +	}
> +	asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
> +#else
> +	asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
> +#endif
> +	/* Make an ARM instructional unconditional */

You meant "instruction" here I suppose.

Otherwise this looks really great.

Acked-by: Nicolas Pitre <nicolas.pitre at linaro.org>


Nicolas