summaryrefslogtreecommitdiff
path: root/arch/powerpc/include/asm/pte-hash32.h
diff options
context:
space:
mode:
authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/powerpc/include/asm/pte-hash32.h
Initial import
Diffstat (limited to 'arch/powerpc/include/asm/pte-hash32.h')
-rw-r--r--arch/powerpc/include/asm/pte-hash32.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pte-hash32.h b/arch/powerpc/include/asm/pte-hash32.h
new file mode 100644
index 000000000..62cfb0c66
--- /dev/null
+++ b/arch/powerpc/include/asm/pte-hash32.h
@@ -0,0 +1,46 @@
+#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_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_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 */