[Xen-devel] [PATCH] linux/x86: utilize lookup_address() for virt_to_ptep()

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

As usual, written and tested on 2.6.25.2 and made apply to the 2.6.18
tree without further testing.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Index: head-2008-05-08/arch/x86_64/mm/pageattr-xen.c
===================================================================
--- head-2008-05-08.orig/arch/x86_64/mm/pageattr-xen.c  2008-05-15 
13:44:37.000000000 +0200
+++ head-2008-05-08/arch/x86_64/mm/pageattr-xen.c       2008-05-15 
14:44:59.000000000 +0200
@@ -276,7 +276,7 @@
 }
 #endif /* CONFIG_XEN */
 
-static inline pte_t *lookup_address(unsigned long address) 
+pte_t *lookup_address(unsigned long address) 
 { 
        pgd_t *pgd = pgd_offset_k(address);
        pud_t *pud;
Index: head-2008-05-08/include/asm-i386/mach-xen/asm/pgtable.h
===================================================================
--- head-2008-05-08.orig/include/asm-i386/mach-xen/asm/pgtable.h        
2008-05-15 13:44:37.000000000 +0200
+++ head-2008-05-08/include/asm-i386/mach-xen/asm/pgtable.h     2008-05-15 
13:38:59.000000000 +0200
@@ -477,19 +477,16 @@ void make_page_writable(void *va, unsign
 void make_pages_readonly(void *va, unsigned int nr, unsigned int feature);
 void make_pages_writable(void *va, unsigned int nr, unsigned int feature);
 
-#define virt_to_ptep(__va)                                             \
-({                                                                     \
-       pgd_t *__pgd = pgd_offset_k((unsigned long)(__va));             \
-       pud_t *__pud = pud_offset(__pgd, (unsigned long)(__va));        \
-       pmd_t *__pmd = pmd_offset(__pud, (unsigned long)(__va));        \
-       pte_offset_kernel(__pmd, (unsigned long)(__va));                \
-})
-
-#define arbitrary_virt_to_machine(__va)                                        
\
-({                                                                     \
-       maddr_t m = (maddr_t)pte_mfn(*virt_to_ptep(__va)) << PAGE_SHIFT;\
-       m | ((unsigned long)(__va) & (PAGE_SIZE-1));                    \
-})
+#define virt_to_ptep(va)                                               \
+({                                                                     \
+       pte_t *__ptep = lookup_address((unsigned long)(va));            \
+       BUG_ON(!__ptep || !pte_present(*__ptep));                       \
+       __ptep;                                                         \
+})
+
+#define arbitrary_virt_to_machine(va)                                  \
+       (((maddr_t)pte_mfn(*virt_to_ptep(va)) << PAGE_SHIFT)            \
+        | ((unsigned long)(va) & (PAGE_SIZE - 1)))
 
 #endif /* !__ASSEMBLY__ */
 
Index: head-2008-05-08/include/asm-x86_64/mach-xen/asm/pgtable.h
===================================================================
--- head-2008-05-08.orig/include/asm-x86_64/mach-xen/asm/pgtable.h      
2008-05-15 13:44:37.000000000 +0200
+++ head-2008-05-08/include/asm-x86_64/mach-xen/asm/pgtable.h   2008-05-15 
13:38:29.000000000 +0200
@@ -18,19 +18,18 @@
 
 extern void xen_init_pt(void);
 
-#define virt_to_ptep(__va)                                             \
-({                                                                     \
-       pgd_t *__pgd = pgd_offset_k((unsigned long)(__va));             \
-       pud_t *__pud = pud_offset(__pgd, (unsigned long)(__va));        \
-       pmd_t *__pmd = pmd_offset(__pud, (unsigned long)(__va));        \
-       pte_offset_kernel(__pmd, (unsigned long)(__va));                \
-})
-
-#define arbitrary_virt_to_machine(__va)                                        
\
-({                                                                     \
-       maddr_t m = (maddr_t)pte_mfn(*virt_to_ptep(__va)) << PAGE_SHIFT;\
-       m | ((unsigned long)(__va) & (PAGE_SIZE-1));                    \
-})
+extern pte_t *lookup_address(unsigned long address);
+
+#define virt_to_ptep(va)                                               \
+({                                                                     \
+       pte_t *__ptep = lookup_address((unsigned long)(va));            \
+       BUG_ON(!__ptep || !pte_present(*__ptep));                       \
+       __ptep;                                                         \
+})
+
+#define arbitrary_virt_to_machine(va)                                  \
+       (((maddr_t)pte_mfn(*virt_to_ptep(va)) << PAGE_SHIFT)            \
+        | ((unsigned long)(va) & (PAGE_SIZE - 1)))
 #endif
 
 extern pud_t level3_kernel_pgt[512];




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