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sh: Free up some and document PTEL flags. 

Drop _PAGE_SHARED/_PAGE_U0_SHARED and document Linux PTE encodings in
the PTEL value. Preserve the swap cache entry encoding semantics for
now, though it will need rework to free up _PAGE_WT from _PAGE_FILE.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2006-09-27 16:17:17 +09:00
parent 801e045860
commit ef48e8e349
1 changed files with 45 additions and 31 deletions
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76
include/asm-sh/pgtable.h
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@ -54,20 +54,41 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define VMALLOC_START (P3SEG+0x00100000)
#define VMALLOC_END (FIXADDR_START-2*PAGE_SIZE)
#define _PAGE_WT 0x001 /* WT-bit on SH-4, 0 on SH-3 */
#define _PAGE_HW_SHARED 0x002 /* SH-bit : page is shared among processes */
#define _PAGE_DIRTY 0x004 /* D-bit : page changed */
#define _PAGE_CACHABLE 0x008 /* C-bit : cachable */
#define _PAGE_SZ0 0x010 /* SZ0-bit : Size of page */
#define _PAGE_RW 0x020 /* PR0-bit : write access allowed */
#define _PAGE_USER 0x040 /* PR1-bit : user space access allowed */
#define _PAGE_SZ1 0x080 /* SZ1-bit : Size of page (on SH-4) */
#define _PAGE_PRESENT 0x100 /* V-bit : page is valid */
#define _PAGE_PROTNONE 0x200 /* software: if not present */
#define _PAGE_ACCESSED 0x400 /* software: page referenced */
#define _PAGE_U0_SHARED 0x800 /* software: page is shared in user space */
#define _PAGE_FILE _PAGE_WT /* software: pagecache or swap? */
/*
* Linux PTEL encoding.
*
* Hardware and software bit definitions for the PTEL value:
*
* - Bits 0 and 7 are reserved on SH-3 (_PAGE_WT and _PAGE_SZ1 on SH-4).
*
* - Bit 1 is the SH-bit, but is unused on SH-3 due to an MMU bug (the
* hardware PTEL value can't have the SH-bit set when MMUCR.IX is set,
* which is the default in cpu-sh3/mmu_context.h:MMU_CONTROL_INIT).
*
* In order to keep this relatively clean, do not use these for defining
* SH-3 specific flags until all of the other unused bits have been
* exhausted.
*
* - Bit 9 is reserved by everyone and used by _PAGE_PROTNONE.
*
* - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
* Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
*
* - Bits 31, 30, and 29 remain unused by everyone and can be used for future
* software flags, although care must be taken to update _PAGE_CLEAR_FLAGS.
*/
#define _PAGE_WT 0x001 /* WT-bit on SH-4, 0 on SH-3 */
#define _PAGE_HW_SHARED 0x002 /* SH-bit : shared among processes */
#define _PAGE_DIRTY 0x004 /* D-bit : page changed */
#define _PAGE_CACHABLE 0x008 /* C-bit : cachable */
#define _PAGE_SZ0 0x010 /* SZ0-bit : Size of page */
#define _PAGE_RW 0x020 /* PR0-bit : write access allowed */
#define _PAGE_USER 0x040 /* PR1-bit : user space access allowed */
#define _PAGE_SZ1 0x080 /* SZ1-bit : Size of page (on SH-4) */
#define _PAGE_PRESENT 0x100 /* V-bit : page is valid */
#define _PAGE_PROTNONE 0x200 /* software: if not present */
#define _PAGE_ACCESSED 0x400 /* software: page referenced */
#define _PAGE_FILE _PAGE_WT /* software: pagecache or swap? */
/* software: moves to PTEA.TC (Timing Control) */
#define _PAGE_PCC_AREA5 0x00000000 /* use BSC registers for area5 */
@ -82,22 +103,17 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define _PAGE_PCC_ATR8 0x60000000 /* Attribute Memory space, 8 bit bus */
#define _PAGE_PCC_ATR16 0x60000001 /* Attribute Memory space, 6 bit bus */
/* Mask which drop software flags
* We also drop WT bit since it is used for _PAGE_FILE
* bit in this implementation.
*/
#define _PAGE_CLEAR_FLAGS (_PAGE_WT | _PAGE_PROTNONE | _PAGE_ACCESSED | _PAGE_U0_SHARED)
#if defined(CONFIG_CPU_SH3)
/*
* MMU on SH-3 has bug on SH-bit: We can't use it if MMUCR.IX=1.
* Work around: Just drop SH-bit.
*/
#define _PAGE_FLAGS_HARDWARE_MASK (0x1fffffff & ~(_PAGE_CLEAR_FLAGS | _PAGE_HW_SHARED))
/* Mask which drops unused bits from the PTEL value */
#ifdef CONFIG_CPU_SH3
#define _PAGE_CLEAR_FLAGS (_PAGE_PROTNONE | _PAGE_ACCESSED| \
_PAGE_FILE | _PAGE_SZ1 | \
_PAGE_HW_SHARED)
#else
#define _PAGE_FLAGS_HARDWARE_MASK (0x1fffffff & ~(_PAGE_CLEAR_FLAGS))
#define _PAGE_CLEAR_FLAGS (_PAGE_PROTNONE | _PAGE_ACCESSED | _PAGE_FILE)
#endif
#define _PAGE_FLAGS_HARDWARE_MASK (0x1fffffff & ~(_PAGE_CLEAR_FLAGS))
/* Hardware flags: SZ0=1 (4k-byte) */
#define _PAGE_FLAGS_HARD _PAGE_SZ0
@ -107,17 +123,15 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define _PAGE_SZHUGE (_PAGE_SZ0 | _PAGE_SZ1)
#endif
#define _PAGE_SHARED _PAGE_U0_SHARED
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY | _PAGE_SHARED)
#define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY)
#ifndef __ASSEMBLY__
#ifdef CONFIG_MMU
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE |_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_CACHABLE |_PAGE_ACCESSED | _PAGE_SHARED | _PAGE_FLAGS_HARD)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_CACHABLE |_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_CACHABLE | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_HW_SHARED | _PAGE_FLAGS_HARD)