Re: [PATCH v5 05/16] ARM: use a function table for determining instructioninterpreter action

[David Long]

On 02/03/14 09:24, Jon Medhurst (Tixy) wrote:
> On Thu, 2014-01-23 at 15:05 -0500, David Long wrote:
> > From: "David A. Long" <dave.long@xxxxxxxxxx>
> >
> > Make the instruction interpreter call back to semantic action functions
> > through a function pointer array provided by the invoker.  The interpreter
> > decodes the instructions into groups and uses the group number to index
> > into the supplied array.  kprobes and uprobes code will each supply their
> > own array of functions.
> >
> > Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>
> > ---
>
> [...]
>
> > --- a/arch/arm/kernel/probes.c
> > +++ b/arch/arm/kernel/probes.c
> > @@ -378,10 +378,11 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
> >    */
> >   int __kprobes
> >   kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
> > -		   const union decode_item *table, bool thumb)
> > +		   const union decode_item *table, bool thumb,
> > +		   const union decode_action *actions)
> >   {
> > -	const struct decode_header *h = (struct decode_header *)table;
> > -	const struct decode_header *next;
> > +	struct decode_header *h = (struct decode_header *)table;
> > +	struct decode_header *next;
>
> The decode tables are fixed structures which nothing should want to
> modify, so I think the const's above should be kept. I believe that
> you've had to resort to changing them because the following typedef
> lacks a 'const' on the final argument....

I've made the change.

> [...]
> > diff --git a/arch/arm/kernel/probes.h b/arch/arm/kernel/probes.h
> > index c610fa9..81b6e61 100644
> [...]
> > +typedef enum kprobe_insn (probes_custom_decode_t)(kprobe_opcode_t,
> > +						  struct arch_specific_insn *,
> > +						  struct decode_header *);
> > +
>
> Adding 'const' above will also have the knock on effect of requiring
> const on all the 'custom decode' functions as well.

I've made those numerous changes as well.

-dl

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