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.a...@oracle.com>
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