Subject: Re: [PATCH v4 13/29] arm64: convert protection key into vm_flags and pgprot values

From: Catalin Marinas <[email-masked]>
Date: Wed, 19 Jun 2024 17:45:29 +0100

On Tue, May 28, 2024 at 12:24:57PM +0530, Amit Daniel Kachhap wrote:
> On 5/3/24 18:31, Joey Gouly wrote:
> > diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
> > index 5966ee4a6154..ecb2d18dc4d7 100644
> > --- a/arch/arm64/include/asm/mman.h
> > +++ b/arch/arm64/include/asm/mman.h
> > @@ -7,7 +7,7 @@
> >   #include <uapi/asm/mman.h>
> >   static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
> > -	unsigned long pkey __always_unused)
> > +	unsigned long pkey)
> >   {
> >   	unsigned long ret = 0;
> > @@ -17,6 +17,12 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
> >   	if (system_supports_mte() && (prot & PROT_MTE))
> >   		ret |= VM_MTE;
> > +#if defined(CONFIG_ARCH_HAS_PKEYS)
> 
> Should there be system_supports_poe() check like above?

I think it should, otherwise we end up with these bits in the pte even
when POE is not supported.

> > +	ret |= pkey & 0x1 ? VM_PKEY_BIT0 : 0;
> > +	ret |= pkey & 0x2 ? VM_PKEY_BIT1 : 0;
> > +	ret |= pkey & 0x4 ? VM_PKEY_BIT2 : 0;
> > +#endif
> > +
> >   	return ret;
> >   }
> >   #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)

-- 
Catalin