mmu.h

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/*
 * CRIS MMU constants and PTE layout
 */

#ifndef _CRIS_MMU_H
#define _CRIS_MMU_H

/* type used in struct mm to couple an MMU context to an active mm */

typedef unsigned int mm_context_t;

/* kernel memory segments */

#define KSEG_F 0xf0000000UL
#define KSEG_E 0xe0000000UL
#define KSEG_D 0xd0000000UL
#define KSEG_C 0xc0000000UL
#define KSEG_B 0xb0000000UL
#define KSEG_A 0xa0000000UL
#define KSEG_9 0x90000000UL
#define KSEG_8 0x80000000UL
#define KSEG_7 0x70000000UL
#define KSEG_6 0x60000000UL
#define KSEG_5 0x50000000UL
#define KSEG_4 0x40000000UL
#define KSEG_3 0x30000000UL
#define KSEG_2 0x20000000UL
#define KSEG_1 0x10000000UL
#define KSEG_0 0x00000000UL

/* CRIS PTE bits (see R_TLB_LO in the register description)
 *
 *   Bit:  31-13 12-------4    3        2       1       0  
 *         ________________________________________________
 *        | pfn | reserved | global | valid | kernel | we  |
 *        |_____|__________|________|_______|________|_____|
 *
 * (pfn = physical frame number)
 */

/* Real HW-based PTE bits. We use some synonym names so that
 * things become less confusing in combination with the SW-based
 * bits further below.
 *
 */

#define _PAGE_WE	   (1<<0) /* page is write-enabled */
#define _PAGE_SILENT_WRITE (1<<0) /* synonym */
#define _PAGE_KERNEL	   (1<<1) /* page is kernel only */
#define _PAGE_VALID	   (1<<2) /* page is valid */
#define _PAGE_SILENT_READ  (1<<2) /* synonym */
#define _PAGE_GLOBAL       (1<<3) /* global page - context is ignored */

/* Bits the HW doesn't care about but the kernel uses them in SW */

#define _PAGE_PRESENT   (1<<4)  /* page present in memory */
#define _PAGE_ACCESSED	(1<<5)  /* simulated in software using valid bit */
#define _PAGE_MODIFIED	(1<<6)  /* simulated in software using we bit */
#define _PAGE_READ      (1<<7)  /* read-enabled */
#define _PAGE_WRITE     (1<<8)  /* write-enabled */

#endif