lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

x86/mm/cpa: Convert noop to functional fix

Browse Source 
Commit:

  a8aed3e075 ("x86/mm/pageattr: Prevent PSE and GLOABL leftovers to confuse pmd/pte_present and pmd_huge")

introduced a valid fix but one location that didn't trigger the bug that
lead to finding those (small) problems, wasn't updated using the
right variable.

The wrong variable was also initialized for no good reason, that
may have been the source of the confusion. Remove the noop
initialization accordingly.

Commit a8aed3e075 also erroneously removed one canon_pgprot pass meant
to clear pmd bitflags not supported in hardware by older CPUs, that
automatically gets corrected by this patch too by applying it to the right
variable in the new location.

Reported-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Mel Gorman <mgorman@suse.de>
Link: http://lkml.kernel.org/r/1365600505-19314-1-git-send-email-aarcange@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andrea Arcangeli 2013-04-10 15:28:25 +02:00 committed by Ingo Molnar
parent 511ba86e1d
commit f76cfa3c24
1 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/mm/pageattr.c
View File

@ -467,7 +467,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
* We are safe now. Check whether the new pgprot is the same:
*/
old_pte = *kpte;
old_prot = new_prot = req_prot = pte_pgprot(old_pte);
old_prot = req_prot = pte_pgprot(old_pte);
pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(req_prot) |= pgprot_val(cpa->mask_set);
@ -478,12 +478,12 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
* a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL
* for the ancient hardware that doesn't support it.
*/
if (pgprot_val(new_prot) & _PAGE_PRESENT)
pgprot_val(new_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
if (pgprot_val(req_prot) & _PAGE_PRESENT)
pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
else
pgprot_val(new_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);
new_prot = canon_pgprot(new_prot);
req_prot = canon_pgprot(req_prot);
/*
* old_pte points to the large page base address. So we need