Re: [PATCH v6] MIPS: micromips: Fix improper definition of ISA exception bit.

[David Daney <ddaney.cavm@gmail.com>]

On 06/05/2013 02:23 PM, Jonas Gorski wrote:
> On Wed, Jun 5, 2013 at 11:15 PM, Steven J. Hill <Steven.Hill@imgtec.com> wrote:
>> On 06/05/2013 03:53 PM, David Daney wrote:
>>>
>>>
>>> You can only manipulate this bit if you know microMIPS is supported.  So
>>> I think you should either not touch it for the non-microMIPS case, or
>>> make the write conditional on the presence of microMIPS support in the
>>> CPU.
>>>
>> I decided to surround with SYS_SUPPORTS_MICROMIPS so the function could be
>> optimized out in v7 of the patch.
>
> Since this is (AFAICT) run after cpu_probe, and cpu probe sets
> MIPS_CPU_MICROMIPS in options[0] if config3 has  MIPS_CONF3_ISA set
> (as seen in the context), couldn't you do just the following in
> cpu_trap:
>
> 	if (cpu_has_mmips) {
> 		unsigned int config3 = read_c0_config3();
>
> 		if (IS_ENABLED(CONFIG_CPU_MICROMIPS))
> 			write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
> 		else
> 			write_c0_config3(config3 & ~MIPS_CONF3_ISA_OE);
> 	}
>

Yes, that would work.  It even looks nicer.

David Daney



>
> Regards
> Jonas
>
>