> +
> +/*
> + * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It
> + * disables preemption so be careful if you intend to use it for long periods
> + * of time.
> + * TODO: If you intend to use the FPU in irq/softirq you need to check first
> with
> + * irq_fpu_usable() if it is possible.
Please avoid the overly lone lines comments.
> +extern bool kernel_fpu_enabled(void);
> +extern void kernel_fpu_begin(void);
> +extern void kernel_fpu_end(void);
No need for the externs.
> +/*
> + * Track whether the kernel is using the FPU state
> + * currently.
This all fits on a single line.
> +static bool fpu_support(void)
> +{
> + if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
> + return true;
> + } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
> + return true;
> + } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
> + return true;
> + }
No need for the braces, or else after a return. In fact this could
be simplified down to:
return cpu_has_feature(CPU_FTR_VSX_COMP) ||
cpu_has_feature(CPU_FTR_ALTIVEC_COMP) ||
cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE));
> + preempt_disable();
> +
> +#ifdef CONFIG_VSX
> + if (cpu_has_feature(CPU_FTR_VSX_COMP)) {
> + enable_kernel_vsx();
> + return;
> + }
> +#endif
> +
> +#ifdef CONFIG_ALTIVEC
> + if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) {
> + enable_kernel_altivec();
> + return;
> + }
> +#endif
> +
> +#ifdef CONFIG_PPC_FPU
> + if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) {
> + enable_kernel_fp();
> + return;
> + }
> +#endif
All the features are defined away if not supported (and we already rely
on that in fpu_support()). So this could become:
if (cpu_has_feature(CPU_FTR_VSX_COMP))
enable_kernel_vsx();
else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP))
enable_kernel_altivec();
else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
enable_kernel_fp();
Same for the disable path.
