Re: [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support
From: Dave Hansen
Date: Tue Oct 13 2020 - 13:50:09 EST
On 10/9/20 12:42 PM, ira.weiny@xxxxxxxxx wrote:
> +/*
> + * Update the pk_reg value and return it.
How about:
Replace disable bits for @pkey with values from @flags.
> + * Kernel users use the same flags as user space:
> + * PKEY_DISABLE_ACCESS
> + * PKEY_DISABLE_WRITE
> + */
> +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> +{
> + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> +
> + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> +
> + if (flags & PKEY_DISABLE_ACCESS)
> + pk_reg |= PKR_AD_BIT << pkey_shift;
> + if (flags & PKEY_DISABLE_WRITE)
> + pk_reg |= PKR_WD_BIT << pkey_shift;
I still think this deserves two lines of comments:
/* Mask out old bit values */
/* Or in new values */