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Diffstat (limited to 'arch/powerpc/include/asm/pte-hash32.h')
-rw-r--r--arch/powerpc/include/asm/pte-hash32.h48
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diff --git a/arch/powerpc/include/asm/pte-hash32.h b/arch/powerpc/include/asm/pte-hash32.h
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+#ifndef _ASM_POWERPC_PTE_HASH32_H
+#define _ASM_POWERPC_PTE_HASH32_H
+#ifdef __KERNEL__
+
+/*
+ * The "classic" 32-bit implementation of the PowerPC MMU uses a hash
+ * table containing PTEs, together with a set of 16 segment registers,
+ * to define the virtual to physical address mapping.
+ *
+ * We use the hash table as an extended TLB, i.e. a cache of currently
+ * active mappings. We maintain a two-level page table tree, much
+ * like that used by the i386, for the sake of the Linux memory
+ * management code. Low-level assembler code in hash_low_32.S
+ * (procedure hash_page) is responsible for extracting ptes from the
+ * tree and putting them into the hash table when necessary, and
+ * updating the accessed and modified bits in the page table tree.
+ */
+
+#define _PAGE_PRESENT 0x001 /* software: pte contains a translation */
+#define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */
+#define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */
+#define _PAGE_USER 0x004 /* usermode access allowed */
+#define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */
+#define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */
+#define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */
+#define _PAGE_WRITETHRU 0x040 /* W: cache write-through */
+#define _PAGE_DIRTY 0x080 /* C: page changed */
+#define _PAGE_ACCESSED 0x100 /* R: page referenced */
+#define _PAGE_EXEC 0x200 /* software: i-cache coherency required */
+#define _PAGE_RW 0x400 /* software: user write access allowed */
+#define _PAGE_SPECIAL 0x800 /* software: Special page */
+
+#ifdef CONFIG_PTE_64BIT
+/* We never clear the high word of the pte */
+#define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE)
+#else
+#define _PTE_NONE_MASK _PAGE_HASHPTE
+#endif
+
+#define _PMD_PRESENT 0
+#define _PMD_PRESENT_MASK (PAGE_MASK)
+#define _PMD_BAD (~PAGE_MASK)
+
+/* Hash table based platforms need atomic updates of the linux PTE */
+#define PTE_ATOMIC_UPDATES 1
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_PTE_HASH32_H */