/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1994 - 2002 by Ralf Baechle * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc. * Copyright (C) 2002 Maciej W. Rozycki */ #ifndef _ASM_PGTABLE_BITS_H #define _ASM_PGTABLE_BITS_H #include <linux/config.h> /* * Note that we shift the lower 32bits of each EntryLo[01] entry * 6 bits to the left. That way we can convert the PFN into the * physical address by a single 'and' operation and gain 6 additional * bits for storing information which isn't present in a normal * MIPS page table. * * Similar to the Alpha port, we need to keep track of the ref * and mod bits in software. We have a software "yeah you can read * from this page" bit, and a hardware one which actually lets the * process read from the page. On the same token we have a software * writable bit and the real hardware one which actually lets the * process write to the page, this keeps a mod bit via the hardware * dirty bit. * * Certain revisions of the R4000 and R5000 have a bug where if a * certain sequence occurs in the last 3 instructions of an executable * page, and the following page is not mapped, the cpu can do * unpredictable things. The code (when it is written) to deal with * this problem will be in the update_mmu_cache() code for the r4k. */ #define _PAGE_PRESENT (1<<0) /* implemented in software */ #define _PAGE_READ (1<<1) /* implemented in software */ #define _PAGE_WRITE (1<<2) /* implemented in software */ #define _PAGE_ACCESSED (1<<3) /* implemented in software */ #define _PAGE_MODIFIED (1<<4) /* implemented in software */ #define _PAGE_FILE (1<<4) /* set:pagecache unset:swap */ #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) #define _PAGE_GLOBAL (1<<8) #define _PAGE_VALID (1<<9) #define _PAGE_SILENT_READ (1<<9) /* synonym */ #define _PAGE_DIRTY (1<<10) /* The MIPS dirty bit */ #define _PAGE_SILENT_WRITE (1<<10) #define _CACHE_UNCACHED (1<<11) #define _CACHE_MASK (1<<11) #define _CACHE_CACHABLE_NONCOHERENT 0 #else #define _PAGE_R4KBUG (1<<5) /* workaround for r4k bug */ #define _PAGE_GLOBAL (1<<6) #define _PAGE_VALID (1<<7) #define _PAGE_SILENT_READ (1<<7) /* synonym */ #define _PAGE_DIRTY (1<<8) /* The MIPS dirty bit */ #define _PAGE_SILENT_WRITE (1<<8) #define _CACHE_MASK (7<<9) #if defined(CONFIG_CPU_SB1) /* No penalty for being coherent on the SB1, so just use it for "noncoherent" spaces, too. Shouldn't hurt. */ #define _CACHE_UNCACHED (2<<9) #define _CACHE_CACHABLE_COW (5<<9) #define _CACHE_CACHABLE_NONCOHERENT (5<<9) #define _CACHE_UNCACHED_ACCELERATED (7<<9) #else #define _CACHE_CACHABLE_NO_WA (0<<9) /* R4600 only */ #define _CACHE_CACHABLE_WA (1<<9) /* R4600 only */ #define _CACHE_UNCACHED (2<<9) /* R4[0246]00 */ #define _CACHE_CACHABLE_NONCOHERENT (3<<9) /* R4[0246]00 */ #define _CACHE_CACHABLE_CE (4<<9) /* R4[04]00MC only */ #define _CACHE_CACHABLE_COW (5<<9) /* R4[04]00MC only */ #define _CACHE_CACHABLE_CUW (6<<9) /* R4[04]00MC only */ #define _CACHE_UNCACHED_ACCELERATED (7<<9) /* R10000 only */ #endif #endif #define __READABLE (_PAGE_READ | _PAGE_SILENT_READ | _PAGE_ACCESSED) #define __WRITEABLE (_PAGE_WRITE | _PAGE_SILENT_WRITE | _PAGE_MODIFIED) #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED | _CACHE_MASK) #ifdef CONFIG_MIPS_UNCACHED #define PAGE_CACHABLE_DEFAULT _CACHE_UNCACHED #elif defined(CONFIG_DMA_NONCOHERENT) #define PAGE_CACHABLE_DEFAULT _CACHE_CACHABLE_NONCOHERENT #else #define PAGE_CACHABLE_DEFAULT _CACHE_CACHABLE_COW #endif #define CONF_CM_DEFAULT (PAGE_CACHABLE_DEFAULT >> 9) #endif /* _ASM_PGTABLE_BITS_H */