lkml.org 
[lkml]   [2008]   [Jan]   [14]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
FromAndi Kleen <>
Subject[PATCH] [18/31] CPA: Make change_page_attr() more robust against use of PAT bits
DateMon, 14 Jan 2008 23:16:50 +0100 (CET)
Use the page table level instead of the PSE bit to check if the PTE 
is for a 4K page or not. This makes the code more robust when the PAT
bit is changed because the PAT bit on 4K pages is in the same position as the
PSE bit.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/x86/mm/pageattr_32.c |    4 ++--
 arch/x86/mm/pageattr_64.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
Index: linux/arch/x86/mm/pageattr_32.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr_32.c
+++ linux/arch/x86/mm/pageattr_32.c
@@ -209,7 +209,7 @@ __change_page_attr(struct page *page, pg
 	set_tlb_flush(address);
 
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) { 
-		if (!pte_huge(*kpte)) {
+		if (level == 3) {
 			set_pte_atomic(kpte, mk_pte(page, prot)); 
 		} else {
 			pgprot_t ref_prot;
@@ -225,7 +225,7 @@ __change_page_attr(struct page *page, pg
 			kpte_page = split;
 		}
 		page_private(kpte_page)++;
-	} else if (!pte_huge(*kpte)) {
+	} else if (level == 3) {
 		set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
 		BUG_ON(page_private(kpte_page) == 0);
 		page_private(kpte_page)--;
Index: linux/arch/x86/mm/pageattr_64.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr_64.c
+++ linux/arch/x86/mm/pageattr_64.c
@@ -184,7 +184,7 @@ __change_page_attr(unsigned long address
 	set_tlb_flush(address);
 
 	if (pgprot_val(prot) != pgprot_val(ref_prot)) { 
-		if (!pte_huge(*kpte)) {
+		if (level == 4) {
 			set_pte(kpte, pfn_pte(pfn, prot));
 		} else {
 			/*
@@ -201,7 +201,7 @@ __change_page_attr(unsigned long address
 			kpte_page = split;
 		}
 		page_private(kpte_page)++;
-	} else if (!pte_huge(*kpte)) {
+	} else if (level == 4) {
 		set_pte(kpte, pfn_pte(pfn, ref_prot));
 		BUG_ON(page_private(kpte_page) == 0);
 		page_private(kpte_page)--;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2008-01-14 22:25    [from the cache]
©2003-2008