Re: [PATCH 43/48] MIPS: math-emu: Set FIR feature flags for full emulation

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

Hello.

On 04/04/2015 01:27 AM, Maciej W. Rozycki wrote:

> Implement FIR feature flags in the FPU emulator according to features
> supported and architecture level requirements.  The W, L and F64 bits
> have only been added at level #2 even though the features they refer to
> were also included with the MIPS64r1 ISA and the W fixed-point format
> also with the MIPS32r1 ISA.

> This is only relevant for the full emulation mode and the emulated CFC1
> instruction as well as ptrace(2) accesses.

> Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
> ---
> linux-mips-emu-fir.diff
> Index: linux/arch/mips/kernel/cpu-probe.c
> ===================================================================
> --- linux.orig/arch/mips/kernel/cpu-probe.c	2015-04-02 20:27:58.700229000 +0100
> +++ linux/arch/mips/kernel/cpu-probe.c	2015-04-02 20:27:58.890231000 +0100
[...]
> @@ -31,11 +32,30 @@
>   #include <asm/spram.h>
>   #include <asm/uaccess.h>
>
> +/*
> + * Set the FIR feature flags for the FPU emulator.
> + */
> +static void cpu_set_nofpu_id(struct cpuinfo_mips *c)
> +{
> +	u32 value;
> +
> +	value = 0;

    Why not just do it in an initializer?

> +	if (c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1 |
> +			    MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
> +			    MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
> +		value |= MIPS_FPIR_D | MIPS_FPIR_S;
> +	if (c->isa_level & (MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2 |
> +			    MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6))
> +		value |= MIPS_FPIR_F64 | MIPS_FPIR_L | MIPS_FPIR_W;
> +	c->fpu_id = value;
> +}
> +
>   static int mips_fpu_disabled;
>
>   static int __init fpu_disable(char *s)
>   {
> -	cpu_data[0].options &= ~MIPS_CPU_FPU;
> +	boot_cpu_data.options &= ~MIPS_CPU_FPU;
> +	cpu_set_nofpu_id(&boot_cpu_data);
>   	mips_fpu_disabled = 1;
>
>   	return 1;
> @@ -1375,7 +1395,8 @@ void cpu_probe(void)
>   			if (c->fpu_id & MIPS_FPIR_FREP)
>   				c->options |= MIPS_CPU_FRE;
>   		}
> -	}
> +	} else
> +		cpu_set_nofpu_id(c);

    CodingStyle: need {} in the *else* branch as well.

[...]

WBR, Sergei