From: Paul Mackerras <paulus@samba.org>
When I tried -mm4 on a ppc32 box, it hit a BUG because I hadn't excluded
_PAGE_FILE from the bits used for swap entries. While looking at that I
realised that the pte_to_pgoff and pgoff_prot_to_pte macros were wrong for
4xx and 8xx (embedded) PPC chips, since they use
---
25-akpm/include/asm-ppc/pgtable.h | 48 ++++++++++++++++++++++++++++++--------
1 files changed, 39 insertions(+), 9 deletions(-)
diff -puN include/asm-ppc/pgtable.h~ppc32-pgtable-fixes include/asm-ppc/pgtable.h
--- 25/include/asm-ppc/pgtable.h~ppc32-pgtable-fixes 2004-03-28 14:39:28.212872352 -0800
+++ 25-akpm/include/asm-ppc/pgtable.h 2004-03-28 14:39:28.215871896 -0800
@@ -202,6 +202,7 @@ extern unsigned long ioremap_bot, iorema
*/
#define _PAGE_PRESENT 0x00000001 /* S: PTE valid */
#define _PAGE_RW 0x00000002 /* S: Write permission */
+#define _PAGE_FILE 0x00000004 /* S: nonlinear file mapping */
#define _PAGE_DIRTY 0x00000004 /* S: Page dirty */
#define _PAGE_ACCESSED 0x00000008 /* S: Page referenced */
#define _PAGE_HWWRITE 0x00000010 /* H: Dirty & RW */
@@ -210,7 +211,6 @@ extern unsigned long ioremap_bot, iorema
#define _PAGE_ENDIAN 0x00000080 /* H: E bit */
#define _PAGE_GUARDED 0x00000100 /* H: G bit */
#define _PAGE_COHERENT 0x00000200 /* H: M bit */
-#define _PAGE_FILE 0x00000400 /* S: nonlinear file mapping */
#define _PAGE_NO_CACHE 0x00000400 /* H: I bit */
#define _PAGE_WRITETHRU 0x00000800 /* H: W bit */
@@ -624,20 +624,50 @@ extern void add_hash_page(unsigned conte
#define __swp_type(entry) ((entry).val & 0x1f)
#define __swp_offset(entry) ((entry).val >> 5)
#define __swp_entry(type, offset) ((swp_entry_t) { (type) | ((offset) << 5) })
+
+#if defined(CONFIG_4xx) || defined(CONFIG_8xx)
+/* _PAGE_FILE and _PAGE_PRESENT are in the bottom 3 bits on all these chips. */
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) >> 3 })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val << 3 })
+#else /* Classic PPC */
+#define __pte_to_swp_entry(pte) \
+ ((swp_entry_t) { ((pte_val(pte) >> 3) & ~1) | ((pte_val(pte) >> 2) & 1) })
+#define __swp_entry_to_pte(x) \
+ ((pte_t) { (((x).val & ~1) << 3) | (((x).val & 1) << 2) })
+#endif
/* Encode and decode a nonlinear file mapping entry */
-#define PTE_FILE_MAX_BITS 27
-#define pte_to_pgoff(pte) (((pte_val(pte) & ~0x7ff) >> 5) \
- | ((pte_val(pte) & 0x3f0) >> 4))
-#define pte_to_pgprot(pte) \
-__pgprot((pte_val(pte) & (_PAGE_USER|_PAGE_RW|_PAGE_PRESENT)) | _PAGE_ACCESSED)
+/* We can't use any the _PAGE_PRESENT, _PAGE_FILE, _PAGE_USER, _PAGE_RW,
+ or _PAGE_HASHPTE bits for storing a page offset. */
+#if defined(CONFIG_40x)
+/* 40x, avoid the 0x53 bits - to simplify things, avoid 0x73 */ */
+#define __pgoff_split(x) ((((x) << 5) & ~0x7f) | (((x) << 2) & 0xc))
+#define __pgoff_glue(x) ((((x) & ~0x7f) >> 5) | (((x) & 0xc) >> 2))
+#elif defined(CONFIG_44x)
+/* 44x, avoid the 0x47 bits */
+#define __pgoff_split(x) ((((x) << 4) & ~0x7f) | (((x) << 3) & 0x38))
+#define __pgoff_glue(x) ((((x) & ~0x7f) >> 4) | (((x) & 0x38) >> 3))
+#elif defined(CONFIG_8xx)
+/* 8xx, avoid the 0x843 bits */
+#define __pgoff_split(x) ((((x) << 4) & ~0xfff) | (((x) << 3) & 0x780) \
+ | (((x) << 2) & 0x3c))
+#define __pgoff_glue(x) ((((x) & ~0xfff) >> 4) | (((x) & 0x780) >> 3))\
+ | (((x) & 0x3c) >> 2))
+#else
+/* classic PPC, avoid the 0x40f bits */
+#define __pgoff_split(x) ((((x) << 5) & ~0x7ff) | (((x) << 4) & 0x3f0))
+#define __pgoff_glue(x) ((((x) & ~0x7ff) >> 5) | (((x) & 0x3f0) >> 4))
+#endif
+#define PTE_FILE_MAX_BITS 27
+#define pte_to_pgoff(pte) __pgoff_glue(pte_val(pte))
#define pgoff_prot_to_pte(off, prot) \
- ((pte_t) { (((off) << 5) & ~0x7ff) | (((off) << 4) & 0x3f0) \
- | (pgprot_val(prot) & (_PAGE_USER|_PAGE_RW)) \
- | _PAGE_FILE })
+ ((pte_t) { __pgoff_split(off) | _PAGE_FILE | \
+ (pgprot_val(prot) & (_PAGE_USER|_PAGE_RW)) })
+
+#define pte_to_pgprot(pte) \
+ __pgprot((pte_val(pte) & (_PAGE_USER|_PAGE_RW|_PAGE_PRESENT)) \
+ | _PAGE_ACCESSED)
/* CONFIG_APUS */
/* For virtual address to physical address conversion */
_