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authorJoakim Tjernlund <joakim.tjernlund@transmode.se>2009-11-20 00:21:03 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-12-09 17:10:36 +1100
commitfe11dc3f9628e5393e932567b7e29d35cbbad136 (patch)
tree32b2513f5799946d42a7b4c912c0fa094763810f /arch/powerpc/include/asm/pte-8xx.h
parent5efab4a02c89c252fb4cce097aafde5f8208dbfe (diff)
powerpc/8xx: Update TLB asm so it behaves as linux mm expects.
Update the TLB asm to make proper use of _PAGE_DIRY and _PAGE_ACCESSED. Get rid of _PAGE_HWWRITE too. Pros: - I/D TLB Miss never needs to write to the linux pte. - _PAGE_ACCESSED is only set on TLB Error fixing accounting - _PAGE_DIRTY is mapped to 0x100, the changed bit, and is set directly when a page has been made dirty. - Proper RO/RW mapping of user space. - Free up 2 SW TLB bits in the linux pte(add back _PAGE_WRITETHRU ?) - kernel RO/user NA support. Cons: - A few more instructions in the TLB Miss routines. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include/asm/pte-8xx.h')
-rw-r--r--arch/powerpc/include/asm/pte-8xx.h13
1 files changed, 6 insertions, 7 deletions
diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h
index dd5ea95fe61e..68ba861331ee 100644
--- a/arch/powerpc/include/asm/pte-8xx.h
+++ b/arch/powerpc/include/asm/pte-8xx.h
@@ -33,21 +33,20 @@
#define _PAGE_NO_CACHE 0x0002 /* I: cache inhibit */
#define _PAGE_SHARED 0x0004 /* No ASID (context) compare */
#define _PAGE_SPECIAL 0x0008 /* SW entry, forced to 0 by the TLB miss */
+#define _PAGE_DIRTY 0x0100 /* C: page changed */
-/* These five software bits must be masked out when the entry is loaded
- * into the TLB.
+/* These 3 software bits must be masked out when the entry is loaded
+ * into the TLB, 2 SW bits left.
*/
#define _PAGE_GUARDED 0x0010 /* software: guarded access */
-#define _PAGE_DIRTY 0x0020 /* software: page changed */
-#define _PAGE_RW 0x0040 /* software: user write access allowed */
-#define _PAGE_ACCESSED 0x0080 /* software: page referenced */
+#define _PAGE_ACCESSED 0x0020 /* software: page referenced */
/* Setting any bits in the nibble with the follow two controls will
* require a TLB exception handler change. It is assumed unused bits
* are always zero.
*/
-#define _PAGE_HWWRITE 0x0100 /* h/w write enable: never set in Linux PTE */
-#define _PAGE_USER 0x0800 /* One of the PP bits, the other is USER&~RW */
+#define _PAGE_RW 0x0400 /* lsb PP bits, inverted in HW */
+#define _PAGE_USER 0x0800 /* msb PP bits */
#define _PMD_PRESENT 0x0001
#define _PMD_BAD 0x0ff0