Re: [PATCH v3] MIPS: micromips: Fix improper definition of ISA exception bit.

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

Hello.

On 04-06-2013 23:09, Steven J. Hill wrote:

> The ISA exception bit selects whether exceptions are taken in classic
> MIPS or microMIPS mode. This bit is Config3.ISAOnExc and is bit 16. It
> It was improperly defined as bits 16 and 17. Fortunately, bit 17 is
> read-only and did not effect microMIPS operation. However, detecting
> a classic or microMIPS kernel when examining the /proc/cpuinfo file,
> the result always showed a microMIPS kernel.

> Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
> ---
>   arch/mips/include/asm/mipsregs.h |    2 +-
>   arch/mips/kernel/cpu-probe.c     |    7 ++-----
>   arch/mips/mti-malta/malta-init.c |    7 +++++++
>   arch/mips/mti-sead3/sead3-init.c |    7 +++++++
>   4 files changed, 17 insertions(+), 6 deletions(-)

[...]
> diff --git a/arch/mips/mti-malta/malta-init.c b/arch/mips/mti-malta/malta-init.c
> index ff8caff..3598f1d 100644
> --- a/arch/mips/mti-malta/malta-init.c
> +++ b/arch/mips/mti-malta/malta-init.c
> @@ -106,6 +106,13 @@ extern struct plat_smp_ops msmtc_smp_ops;
>
>   void __init prom_init(void)
>   {
> +#ifdef CONFIG_CPU_MICROMIPS
> +	unsigned int config3 = read_c0_config3();
> +
> +	if (config3 & MIPS_CONF3_ISA)
> +		write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
> +#endif
> +
>   	mips_display_message("LINUX");
>
>   	/*
> diff --git a/arch/mips/mti-sead3/sead3-init.c b/arch/mips/mti-sead3/sead3-init.c
> index bfbd17b..e68bfd3 100644
> --- a/arch/mips/mti-sead3/sead3-init.c
> +++ b/arch/mips/mti-sead3/sead3-init.c
> @@ -130,6 +130,13 @@ static void __init mips_ejtag_setup(void)
>
>   void __init prom_init(void)
>   {
> +#ifdef CONFIG_CPU_MICROMIPS
> +	unsigned int config3 = read_c0_config3();
> +
> +	if (config3 & MIPS_CONF3_ISA)
> +		write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
> +#endif
> +

    I see it's repeated twice and enclosed in #ifdef... Couldn't you
factor it out in some sort of inline function and put into some header:

#ifdef CONFIG_CPU_MICROMIPS
static inline void mips_set_config3_isa_oe(void)
{
	unsigned int config3 = read_c0_config3();

	if (config3 & MIPS_CONF3_ISA)
		write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
}
#else
static inline void mips_set_config3_isa_oe(void) {}
#endif

WBR, Sergei