[tip:x86/pti] x86/mm: Remove extra filtering in pageattr code
Commit-ID: 1a54420aeb4da1ba5b28283aa5696898220c9a27
Gitweb: https://git.kernel.org/tip/1a54420aeb4da1ba5b28283aa5696898220c9a27
Author: Dave Hansen
AuthorDate: Fri, 6 Apr 2018 13:55:11 -0700
Committer: Ingo Molnar
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
Cc: Andrea Arcangeli
Cc: Andy Lutomirski
Cc: Arjan van de Ven
Cc: Borislav Petkov
Cc: Dan Williams
Cc: David Woodhouse
Cc: Greg Kroah-Hartman
Cc: Hugh Dickins
Cc: Josh Poimboeuf
Cc: Juergen Gross
Cc: Kees Cook
Cc: Linus Torvalds
Cc: Nadav Amit
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux...@kvack.org
Link: http://lkml.kernel.org/r/20180406205511.bc072...@viggo.jf.intel.com
Signed-off-by: Ingo Molnar
---
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 ?
[tip:x86/pti] x86/mm: Remove extra filtering in pageattr code
Commit-ID: e71e836f463dd2cfb319ce88ae4a6e4f83904e6c
Gitweb: https://git.kernel.org/tip/e71e836f463dd2cfb319ce88ae4a6e4f83904e6c
Author: Dave Hansen
AuthorDate: Fri, 6 Apr 2018 13:55:11 -0700
Committer: Ingo Molnar
CommitDate: Mon, 9 Apr 2018 18:27:33 +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
Cc: Andrea Arcangeli
Cc: Andy Lutomirski
Cc: Arjan van de Ven
Cc: Borislav Petkov
Cc: Dan Williams
Cc: David Woodhouse
Cc: Greg Kroah-Hartman
Cc: Hugh Dickins
Cc: Josh Poimboeuf
Cc: Juergen Gross
Cc: Kees Cook
Cc: Linus Torvalds
Cc: Nadav Amit
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux...@kvack.org
Link: http://lkml.kernel.org/r/20180406205511.bc072...@viggo.jf.intel.com
Signed-off-by: Ingo Molnar
---
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 ?
