Jan Beulich
2006-Dec-12 16:24 UTC
[Xen-devel] [PATCH] tighten requirements on lXe_write() & Co.
This patch allows spotting incorrect use of lXe_write & Co in cases like
void test_pte_write_1(l1_pgentry_t *pl1e, l2_pgentry_t nl2e)
{
l2e_write(pl1e, nl2e);
}
void test_pte_write_2(const l1_pgentry_t *pcl1e, l1_pgentry_t nl1e)
{
l1e_write(pcl1e, nl1e);
}
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Index: 2006-12-11/xen/include/asm-x86/page.h
==================================================================---
2006-12-11.orig/xen/include/asm-x86/page.h 2006-12-12 14:56:46.000000000 +0100
+++ 2006-12-11/xen/include/asm-x86/page.h 2006-12-12 15:06:51.000000000 +0100
@@ -26,25 +26,25 @@
#endif
/* Read a pte atomically from memory. */
-#define l1e_read_atomic(l1ep) l1e_from_intpte(pte_read_atomic(l1ep))
-#define l2e_read_atomic(l2ep) l2e_from_intpte(pte_read_atomic(l2ep))
-#define l3e_read_atomic(l3ep) l3e_from_intpte(pte_read_atomic(l3ep))
-#define l4e_read_atomic(l4ep) l4e_from_intpte(pte_read_atomic(l4ep))
+#define l1e_read_atomic(l1ep)
l1e_from_intpte(pte_read_atomic(&l1e_get_intpte(*(l1ep))))
+#define l2e_read_atomic(l2ep)
l2e_from_intpte(pte_read_atomic(&l2e_get_intpte(*(l2ep))))
+#define l3e_read_atomic(l3ep)
l3e_from_intpte(pte_read_atomic(&l3e_get_intpte(*(l3ep))))
+#define l4e_read_atomic(l4ep)
l4e_from_intpte(pte_read_atomic(&l4e_get_intpte(*(l4ep))))
/* Write a pte atomically to memory. */
-#define l1e_write_atomic(l1ep, l1e) pte_write_atomic(l1ep, l1e_get_intpte(l1e))
-#define l2e_write_atomic(l2ep, l2e) pte_write_atomic(l2ep, l2e_get_intpte(l2e))
-#define l3e_write_atomic(l3ep, l3e) pte_write_atomic(l3ep, l3e_get_intpte(l3e))
-#define l4e_write_atomic(l4ep, l4e) pte_write_atomic(l4ep, l4e_get_intpte(l4e))
+#define l1e_write_atomic(l1ep, l1e)
pte_write_atomic(&l1e_get_intpte(*(l1ep)), l1e_get_intpte(l1e))
+#define l2e_write_atomic(l2ep, l2e)
pte_write_atomic(&l2e_get_intpte(*(l2ep)), l2e_get_intpte(l2e))
+#define l3e_write_atomic(l3ep, l3e)
pte_write_atomic(&l3e_get_intpte(*(l3ep)), l3e_get_intpte(l3e))
+#define l4e_write_atomic(l4ep, l4e)
pte_write_atomic(&l4e_get_intpte(*(l4ep)), l4e_get_intpte(l4e))
/*
* Write a pte safely but non-atomically to memory.
* The PTE may become temporarily not-present during the update.
*/
-#define l1e_write(l1ep, l1e) pte_write(l1ep, l1e_get_intpte(l1e))
-#define l2e_write(l2ep, l2e) pte_write(l2ep, l2e_get_intpte(l2e))
-#define l3e_write(l3ep, l3e) pte_write(l3ep, l3e_get_intpte(l3e))
-#define l4e_write(l4ep, l4e) pte_write(l4ep, l4e_get_intpte(l4e))
+#define l1e_write(l1ep, l1e) pte_write(&l1e_get_intpte(*(l1ep)),
l1e_get_intpte(l1e))
+#define l2e_write(l2ep, l2e) pte_write(&l2e_get_intpte(*(l2ep)),
l2e_get_intpte(l2e))
+#define l3e_write(l3ep, l3e) pte_write(&l3e_get_intpte(*(l3ep)),
l3e_get_intpte(l3e))
+#define l4e_write(l4ep, l4e) pte_write(&l4e_get_intpte(*(l4ep)),
l4e_get_intpte(l4e))
/* Get direct integer representation of a pte''s contents (intpte_t).
*/
#define l1e_get_intpte(x) ((x).l1)
Index: 2006-12-11/xen/include/asm-x86/x86_32/page-2level.h
==================================================================---
2006-12-11.orig/xen/include/asm-x86/x86_32/page-2level.h 2006-12-12
14:56:46.000000000 +0100
+++ 2006-12-11/xen/include/asm-x86/x86_32/page-2level.h 2006-12-12
15:06:51.000000000 +0100
@@ -28,9 +28,9 @@ typedef l2_pgentry_t root_pgentry_t;
#endif /* !__ASSEMBLY__ */
-#define pte_read_atomic(ptep) (*(intpte_t *)(ptep))
-#define pte_write_atomic(ptep, pte) ((*(intpte_t *)(ptep)) = (pte))
-#define pte_write(ptep, pte) ((*(intpte_t *)(ptep)) = (pte))
+#define pte_read_atomic(ptep) (*(ptep))
+#define pte_write_atomic(ptep, pte) (*(ptep) = (pte))
+#define pte_write(ptep, pte) (*(ptep) = (pte))
/* root table */
#define root_get_pfn l2e_get_pfn
Index: 2006-12-11/xen/include/asm-x86/x86_32/page-3level.h
==================================================================---
2006-12-11.orig/xen/include/asm-x86/x86_32/page-3level.h 2006-12-12
14:56:46.000000000 +0100
+++ 2006-12-11/xen/include/asm-x86/x86_32/page-3level.h 2006-12-12
15:27:19.000000000 +0100
@@ -38,22 +38,23 @@ typedef l3_pgentry_t root_pgentry_t;
#endif /* !__ASSEMBLY__ */
-#define pte_read_atomic(ptep) ({ \
- intpte_t __pte = *(intpte_t *)(ptep), __npte; \
- while ( (__npte = cmpxchg((intpte_t *)(ptep), __pte, __pte)) != __pte ) \
- __pte = __npte; \
+#define pte_read_atomic(ptep) ({ \
+ intpte_t __pte = *(ptep), __npte; \
+ while ( (__npte = cmpxchg(ptep, __pte, __pte)) != __pte ) \
+ __pte = __npte; \
__pte; })
-#define pte_write_atomic(ptep, pte) do { \
- intpte_t __pte = *(intpte_t *)(ptep), __npte; \
- while ( (__npte = cmpxchg((intpte_t *)(ptep), __pte, (pte))) != __pte ) \
- __pte = __npte; \
+#define pte_write_atomic(ptep, pte) do { \
+ intpte_t __pte = *(ptep), __npte; \
+ while ( (__npte = cmpxchg(ptep, __pte, (pte))) != __pte ) \
+ __pte = __npte; \
} while ( 0 )
-#define pte_write(ptep, pte) do { \
- *((u32 *)(ptep)+0) = 0; \
- wmb(); \
- *((u32 *)(ptep)+1) = (pte) >> 32; \
- wmb(); \
- *((u32 *)(ptep)+0) = (pte) >> 0; \
+#define pte_write(ptep, pte) do { \
+ union { intpte_t *_ptep; u32 *parts; } __ptep = { ptep }; \
+ __ptep.parts[0] = 0; \
+ wmb(); \
+ __ptep.parts[1] = (pte) >> 32; \
+ wmb(); \
+ __ptep.parts[0] = (pte) >> 0; \
} while ( 0 )
/* root table */
Index: 2006-12-11/xen/include/asm-x86/x86_64/page.h
==================================================================---
2006-12-11.orig/xen/include/asm-x86/x86_64/page.h 2006-12-12 14:56:46.000000000
+0100
+++ 2006-12-11/xen/include/asm-x86/x86_64/page.h 2006-12-12 15:06:51.000000000
+0100
@@ -43,9 +43,9 @@ typedef l4_pgentry_t root_pgentry_t;
#endif /* !__ASSEMBLY__ */
-#define pte_read_atomic(ptep) (*(intpte_t *)(ptep))
-#define pte_write_atomic(ptep, pte) ((*(intpte_t *)(ptep)) = (pte))
-#define pte_write(ptep, pte) ((*(intpte_t *)(ptep)) = (pte))
+#define pte_read_atomic(ptep) (*(ptep))
+#define pte_write_atomic(ptep, pte) (*(ptep) = (pte))
+#define pte_write(ptep, pte) (*(ptep) = (pte))
/* Given a virtual address, get an entry offset into a linear page table. */
#define l1_linear_offset(_a) (((_a) & VADDR_MASK) >>
L1_PAGETABLE_SHIFT)
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