Re: [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support

On 10/9/20 12:42 PM, ira.weiny@intel.com 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 */