diff options
| author | Joakim Tjernlund <joakim.tjernlund@transmode.se> | 2009-11-20 00:21:03 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-12-09 17:10:36 +1100 |
| commit | fe11dc3f9628e5393e932567b7e29d35cbbad136 (patch) | |
| tree | 32b2513f5799946d42a7b4c912c0fa094763810f /arch/powerpc/include/asm | |
| parent | 5efab4a02c89c252fb4cce097aafde5f8208dbfe (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')
| -rw-r--r-- | arch/powerpc/include/asm/pte-8xx.h | 13 |
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 dd5ea95fe61..68ba861331e 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 |