Re: [PATCH v7 9/9] sparc64: Add support for ADI (Application Data Integrity)

[Khalid Aziz]

On 08/15/2017 10:58 PM, David Miller wrote:
> From: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
> Date: Wed,  9 Aug 2017 15:26:02 -0600
>
> > +void adi_restore_tags(struct mm_struct *mm, struct vm_area_struct *vma,
> > +		      unsigned long addr, pte_t pte)
> > +{
>   ...
> > +	tag = tag_start(addr, tag_desc);
> > +	paddr = pte_val(pte) & _PAGE_PADDR_4V;
> > +	for (tmp = paddr; tmp < (paddr+PAGE_SIZE); tmp += adi_blksize()) {
> > +		version1 = (*tag) >> 4;
> > +		version2 = (*tag) & 0x0f;
> > +		*tag++ = 0;
> > +		asm volatile("stxa %0, [%1] %2\n\t"
> > +			:
> > +			: "r" (version1), "r" (tmp),
> > +			  "i" (ASI_MCD_REAL));
> > +		tmp += adi_blksize();
> > +		asm volatile("stxa %0, [%1] %2\n\t"
> > +			:
> > +			: "r" (version2), "r" (tmp),
> > +			  "i" (ASI_MCD_REAL));
> > +	}
> > +	asm volatile("membar #Sync\n\t");
>
> You do a membar here.
>
> > +		for (i = pfrom; i < (pfrom + PAGE_SIZE); i += adi_blksize()) {
> > +			asm volatile("ldxa [%1] %2, %0\n\t"
> > +					: "=r" (adi_tag)
> > +					:  "r" (i), "i" (ASI_MCD_REAL));
> > +			asm volatile("stxa %0, [%1] %2\n\t"
> > +					:
> > +					: "r" (adi_tag), "r" (pto),
> > +					  "i" (ASI_MCD_REAL));
>
> But not here.
>
> Is this OK?  I suspect you need to add a membar this this second piece
> of MCD tag storing code.

Hi Dave,

You are right. This tag storing code needs membar as well. I will add that.

Thanks,
Khalid