pgtable.h

linux-2.4.29操作系统的源码

/*
 *  linux/include/asm-arm/proc-armv/pgtable.h
 *
 *  Copyright (C) 1995-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  12-Jan-1997	RMK	Altered flushing routines to use function pointers
 *			now possible to combine ARM6, ARM7 and StrongARM versions.
 *  17-Apr-1999	RMK	Now pass an area size to clean_cache_area and
 *			flush_icache_area.
 */
#ifndef __ASM_PROC_PGTABLE_H
#define __ASM_PROC_PGTABLE_H

#include <asm/proc/domain.h>
#include <asm/arch/vmalloc.h>

/*
 * entries per page directory level: they are two-level, so
 * we don't really have any PMD directory.
 */
#define PTRS_PER_PTE		256
#define PTRS_PER_PMD		1
#define PTRS_PER_PGD		4096

/****************
* PMD functions *
****************/

/* PMD types (actually level 1 descriptor) */
#define PMD_TYPE_MASK		0x0003
#define PMD_TYPE_FAULT		0x0000
#define PMD_TYPE_TABLE		0x0001
#define PMD_TYPE_SECT		0x0002
#define PMD_UPDATABLE		0x0010
#define PMD_SECT_CACHEABLE	0x0008
#define PMD_SECT_BUFFERABLE	0x0004
#define PMD_SECT_AP_WRITE	0x0400
#define PMD_SECT_AP_READ	0x0800
#define PMD_DOMAIN(x)		((x) << 5)

#define _PAGE_USER_TABLE	(PMD_TYPE_TABLE | PMD_DOMAIN(DOMAIN_USER))
#define _PAGE_KERNEL_TABLE	(PMD_TYPE_TABLE | PMD_DOMAIN(DOMAIN_KERNEL))

#define pmd_bad(pmd)		(pmd_val(pmd) & 2)
#define set_pmd(pmdp,pmd)	cpu_set_pmd(pmdp,pmd)

static inline pmd_t __mk_pmd(pte_t *ptep, unsigned long prot)
{
	unsigned long pte_ptr = (unsigned long)ptep;
	pmd_t pmd;

	pte_ptr -= PTRS_PER_PTE * sizeof(void *);

	/*
	 * The pmd must be loaded with the physical
	 * address of the PTE table
	 */
	pmd_val(pmd) = __virt_to_phys(pte_ptr) | prot;

	return pmd;
}

static inline unsigned long pmd_page(pmd_t pmd)
{
	unsigned long ptr;

	ptr = pmd_val(pmd) & ~(PTRS_PER_PTE * sizeof(void *) - 1);

	ptr += PTRS_PER_PTE * sizeof(void *);

	return __phys_to_virt(ptr);
}

/****************
* PTE functions *
****************/

/* PTE types (actually level 2 descriptor) */
#define PTE_TYPE_MASK		0x0003
#define PTE_TYPE_FAULT		0x0000
#define PTE_TYPE_LARGE		0x0001
#define PTE_TYPE_SMALL		0x0002
#define PTE_AP_READ		0x0aa0
#define PTE_AP_WRITE		0x0550
#define PTE_CACHEABLE		0x0008
#define PTE_BUFFERABLE		0x0004

#define set_pte(ptep, pte)	cpu_set_pte(ptep,pte)

/* We now keep two sets of ptes - the physical and the linux version.
 * This gives us many advantages, and allows us greater flexibility.
 *
 * The Linux pte's contain:
 *  bit   meaning
 *   0    page present
 *   1    young
 *   2    bufferable	- matches physical pte
 *   3    cacheable	- matches physical pte
 *   4    user
 *   5    write
 *   6    execute
 *   7    dirty
 *  8-11  unused
 *  12-31 virtual page address
 *
 * These are stored at the pte pointer; the physical PTE is at -1024bytes
 */
#define L_PTE_PRESENT		(1 << 0)
#define L_PTE_YOUNG		(1 << 1)
#define L_PTE_BUFFERABLE	(1 << 2)
#define L_PTE_CACHEABLE		(1 << 3)
#define L_PTE_USER		(1 << 4)
#define L_PTE_WRITE		(1 << 5)
#define L_PTE_EXEC		(1 << 6)
#define L_PTE_DIRTY		(1 << 7)

/*
 * The following macros handle the cache and bufferable bits...
 */
#define _L_PTE_DEFAULT	L_PTE_PRESENT | L_PTE_YOUNG
#define _L_PTE_READ	L_PTE_USER | L_PTE_CACHEABLE | L_PTE_BUFFERABLE

#define PAGE_NONE       __pgprot(_L_PTE_DEFAULT)
#define PAGE_COPY       __pgprot(_L_PTE_DEFAULT | _L_PTE_READ)
#define PAGE_SHARED     __pgprot(_L_PTE_DEFAULT | _L_PTE_READ | L_PTE_WRITE)
#define PAGE_READONLY   __pgprot(_L_PTE_DEFAULT | _L_PTE_READ)
#define PAGE_KERNEL     __pgprot(_L_PTE_DEFAULT | L_PTE_CACHEABLE | L_PTE_BUFFERABLE | L_PTE_DIRTY | L_PTE_WRITE)

#define _PAGE_CHG_MASK	(PAGE_MASK | L_PTE_DIRTY | L_PTE_YOUNG)


/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
#define pte_present(pte)		(pte_val(pte) & L_PTE_PRESENT)
#define pte_read(pte)			(pte_val(pte) & L_PTE_USER)
#define pte_write(pte)			(pte_val(pte) & L_PTE_WRITE)
#define pte_exec(pte)			(pte_val(pte) & L_PTE_EXEC)
#define pte_dirty(pte)			(pte_val(pte) & L_PTE_DIRTY)
#define pte_young(pte)			(pte_val(pte) & L_PTE_YOUNG)

#define PTE_BIT_FUNC(fn,op)			\
static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }

/*PTE_BIT_FUNC(rdprotect, &= ~L_PTE_USER);*/
/*PTE_BIT_FUNC(mkread,    |= L_PTE_USER);*/
PTE_BIT_FUNC(wrprotect, &= ~L_PTE_WRITE);
PTE_BIT_FUNC(mkwrite,   |= L_PTE_WRITE);
PTE_BIT_FUNC(exprotect, &= ~L_PTE_EXEC);
PTE_BIT_FUNC(mkexec,    |= L_PTE_EXEC);
PTE_BIT_FUNC(mkclean,   &= ~L_PTE_DIRTY);
PTE_BIT_FUNC(mkdirty,   |= L_PTE_DIRTY);
PTE_BIT_FUNC(mkold,     &= ~L_PTE_YOUNG);
PTE_BIT_FUNC(mkyoung,   |= L_PTE_YOUNG);

/*
 * Mark the prot value as uncacheable and unbufferable.
 */
#define pgprot_noncached(prot)	__pgprot(pgprot_val(prot) & ~(L_PTE_CACHEABLE | L_PTE_BUFFERABLE))

#endif /* __ASM_PROC_PGTABLE_H */