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authorThomas Gleixner <tglx@linutronix.de>2008-02-04 10:48:07 -0500
committerIngo Molnar <mingo@elte.hu>2008-02-04 10:48:07 -0500
commit9a14aefc1d28c6037122965ee8c10d92a970ade0 (patch)
tree8f1342c4f18d075009abc9e4f05a6d4e4ba97640 /arch/x86/mm/pageattr.c
parent34508f66b69ff1708192654f631eb8f1d4c52005 (diff)
x86: cpa, fix lookup_address
lookup_address() returns a wrong level and a wrong pointer to a non existing pte, when pmd or pud entries are marked !present. This happens for example due to boot time mapping of GART into the low memory space. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
-rw-r--r--arch/x86/mm/pageattr.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 3810f7a83b1d..7d21cd658ed3 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -188,6 +188,14 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address)
188 return prot; 188 return prot;
189} 189}
190 190
191/*
192 * Lookup the page table entry for a virtual address. Return a pointer
193 * to the entry and the level of the mapping.
194 *
195 * Note: We return pud and pmd either when the entry is marked large
196 * or when the present bit is not set. Otherwise we would return a
197 * pointer to a nonexisting mapping.
198 */
191pte_t *lookup_address(unsigned long address, int *level) 199pte_t *lookup_address(unsigned long address, int *level)
192{ 200{
193 pgd_t *pgd = pgd_offset_k(address); 201 pgd_t *pgd = pgd_offset_k(address);
@@ -206,7 +214,7 @@ pte_t *lookup_address(unsigned long address, int *level)
206 return NULL; 214 return NULL;
207 215
208 *level = PG_LEVEL_2M; 216 *level = PG_LEVEL_2M;
209 if (pmd_large(*pmd)) 217 if (pmd_large(*pmd) || !pmd_present(*pmd))
210 return (pte_t *)pmd; 218 return (pte_t *)pmd;
211 219
212 *level = PG_LEVEL_4K; 220 *level = PG_LEVEL_4K;