linux/include/asm-i386/page.h
Mark Lord 975b3d3d5b [PATCH] VMSPLIT config options
Enable selection of different user/kernel VM splits for i386, including an
optimized mode for 1GB physical RAM, which gives the kernel a direct (non
HIGHMEM) mapping to the entire 1GB rather than just the first 896MB.

There is a similarly a similarly optimized mode for machines with exactly 2GB
of physical RAM.

This can speed up the kernel by avoiding having to create/destroy temporary
HIGHMEM mappings, and by not having to include HIGHMEM support at all on such
machines.  The flip side is that there's less virtual addressing left for
userspace in these alternatives, and some binary-only kernel modules may
misbehave unless rebuilt with the same VMSPLIT option as the main kernel
image.

Original idea/patch from Jens Axboe, modified based on suggestions from Linus
et al.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:21 -08:00

147 lines
4.2 KiB
C

#ifndef _I386_PAGE_H
#define _I386_PAGE_H
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#define PAGE_SIZE (1UL << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1))
#define LARGE_PAGE_SIZE (1UL << PMD_SHIFT)
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <linux/config.h>
#ifdef CONFIG_X86_USE_3DNOW
#include <asm/mmx.h>
#define clear_page(page) mmx_clear_page((void *)(page))
#define copy_page(to,from) mmx_copy_page(to,from)
#else
/*
* On older X86 processors it's not a win to use MMX here it seems.
* Maybe the K6-III ?
*/
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
#endif
#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#define alloc_zeroed_user_highpage(vma, vaddr) alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO, vma, vaddr)
#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
/*
* These are used to make use of C type-checking..
*/
extern int nx_enabled;
#ifdef CONFIG_X86_PAE
extern unsigned long long __supported_pte_mask;
typedef struct { unsigned long pte_low, pte_high; } pte_t;
typedef struct { unsigned long long pmd; } pmd_t;
typedef struct { unsigned long long pgd; } pgd_t;
typedef struct { unsigned long long pgprot; } pgprot_t;
#define pmd_val(x) ((x).pmd)
#define pte_val(x) ((x).pte_low | ((unsigned long long)(x).pte_high << 32))
#define __pmd(x) ((pmd_t) { (x) } )
#define HPAGE_SHIFT 21
#else
typedef struct { unsigned long pte_low; } pte_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
#define boot_pte_t pte_t /* or would you rather have a typedef */
#define pte_val(x) ((x).pte_low)
#define HPAGE_SHIFT 22
#endif
#define PTE_MASK PAGE_MASK
#ifdef CONFIG_HUGETLB_PAGE
#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
#endif
#define pgd_val(x) ((x).pgd)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) } )
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
#endif /* !__ASSEMBLY__ */
/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
/*
* This handles the memory map.. We could make this a config
* option, but too many people screw it up, and too few need
* it.
*
* A __PAGE_OFFSET of 0xC0000000 means that the kernel has
* a virtual address space of one gigabyte, which limits the
* amount of physical memory you can use to about 950MB.
*
* If you want more physical memory than this then see the CONFIG_HIGHMEM4G
* and CONFIG_HIGHMEM64G options in the kernel configuration.
*/
#ifndef __ASSEMBLY__
/*
* This much address space is reserved for vmalloc() and iomap()
* as well as fixmap mappings.
*/
extern unsigned int __VMALLOC_RESERVE;
extern int sysctl_legacy_va_layout;
extern int page_is_ram(unsigned long pagenr);
#endif /* __ASSEMBLY__ */
#ifdef __ASSEMBLY__
#define __PAGE_OFFSET CONFIG_PAGE_OFFSET
#define __PHYSICAL_START CONFIG_PHYSICAL_START
#else
#define __PAGE_OFFSET ((unsigned long)CONFIG_PAGE_OFFSET)
#define __PHYSICAL_START ((unsigned long)CONFIG_PHYSICAL_START)
#endif
#define __KERNEL_START (__PAGE_OFFSET + __PHYSICAL_START)
#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
#define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
#ifdef CONFIG_FLATMEM
#define pfn_to_page(pfn) (mem_map + (pfn))
#define page_to_pfn(page) ((unsigned long)((page) - mem_map))
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#endif /* CONFIG_FLATMEM */
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define VM_DATA_DEFAULT_FLAGS \
(VM_READ | VM_WRITE | \
((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
#endif /* __KERNEL__ */
#include <asm-generic/page.h>
#endif /* _I386_PAGE_H */