Commit-ID: 1a54420aeb4da1ba5b28283aa5696898220c9a27 Gitweb: https://git.kernel.org/tip/1a54420aeb4da1ba5b28283aa5696898220c9a27 Author: Dave Hansen <[email protected]> AuthorDate: Fri, 6 Apr 2018 13:55:11 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 12 Apr 2018 09:05:58 +0200
x86/mm: Remove extra filtering in pageattr code The pageattr code has a mode where it can set or clear PTE bits in existing PTEs, so the page protections of the *new* PTEs come from one of two places: 1. The set/clear masks: cpa->mask_clr / cpa->mask_set 2. The existing PTE We filter ->mask_set/clr for supported PTE bits at entry to __change_page_attr() so we never need to filter them again. The only other place permissions can come from is an existing PTE and those already presumably have good bits. We do not need to filter them again. Signed-off-by: Dave Hansen <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dan Williams <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Nadav Amit <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/mm/pageattr.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index d3442dfdfced..968f51a2e39b 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -598,7 +598,6 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, req_prot = pgprot_clear_protnone_bits(req_prot); if (pgprot_val(req_prot) & _PAGE_PRESENT) pgprot_val(req_prot) |= _PAGE_PSE; - req_prot = canon_pgprot(req_prot); /* * old_pfn points to the large page base pfn. So we need @@ -718,7 +717,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, */ pfn = ref_pfn; for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc) - set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot))); + set_pte(&pbase[i], pfn_pte(pfn, ref_prot)); if (virt_addr_valid(address)) { unsigned long pfn = PFN_DOWN(__pa(address)); @@ -935,7 +934,6 @@ static void populate_pte(struct cpa_data *cpa, pte = pte_offset_kernel(pmd, start); pgprot = pgprot_clear_protnone_bits(pgprot); - pgprot = canon_pgprot(pgprot); while (num_pages-- && start < end) { set_pte(pte, pfn_pte(cpa->pfn, pgprot)); @@ -1234,7 +1232,7 @@ repeat: * after all we're only going to change it's attributes * not the memory it points to */ - new_pte = pfn_pte(pfn, canon_pgprot(new_prot)); + new_pte = pfn_pte(pfn, new_prot); cpa->pfn = pfn; /* * Do we really change anything ?
