280 lines
7.9 KiB
C
280 lines
7.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_HIGHMEM_H
|
|
#define _LINUX_HIGHMEM_H
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/bug.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/hardirq.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
|
|
#include "highmem-internal.h"
|
|
|
|
/**
|
|
* kmap - Map a page for long term usage
|
|
* @page: Pointer to the page to be mapped
|
|
*
|
|
* Returns: The virtual address of the mapping
|
|
*
|
|
* Can only be invoked from preemptible task context because on 32bit
|
|
* systems with CONFIG_HIGHMEM enabled this function might sleep.
|
|
*
|
|
* For systems with CONFIG_HIGHMEM=n and for pages in the low memory area
|
|
* this returns the virtual address of the direct kernel mapping.
|
|
*
|
|
* The returned virtual address is globally visible and valid up to the
|
|
* point where it is unmapped via kunmap(). The pointer can be handed to
|
|
* other contexts.
|
|
*
|
|
* For highmem pages on 32bit systems this can be slow as the mapping space
|
|
* is limited and protected by a global lock. In case that there is no
|
|
* mapping slot available the function blocks until a slot is released via
|
|
* kunmap().
|
|
*/
|
|
static inline void *kmap(struct page *page);
|
|
|
|
/**
|
|
* kunmap - Unmap the virtual address mapped by kmap()
|
|
* @addr: Virtual address to be unmapped
|
|
*
|
|
* Counterpart to kmap(). A NOOP for CONFIG_HIGHMEM=n and for mappings of
|
|
* pages in the low memory area.
|
|
*/
|
|
static inline void kunmap(struct page *page);
|
|
|
|
/**
|
|
* kmap_to_page - Get the page for a kmap'ed address
|
|
* @addr: The address to look up
|
|
*
|
|
* Returns: The page which is mapped to @addr.
|
|
*/
|
|
static inline struct page *kmap_to_page(void *addr);
|
|
|
|
/**
|
|
* kmap_flush_unused - Flush all unused kmap mappings in order to
|
|
* remove stray mappings
|
|
*/
|
|
static inline void kmap_flush_unused(void);
|
|
|
|
/**
|
|
* kmap_local_page - Map a page for temporary usage
|
|
* @page: Pointer to the page to be mapped
|
|
*
|
|
* Returns: The virtual address of the mapping
|
|
*
|
|
* Can be invoked from any context.
|
|
*
|
|
* Requires careful handling when nesting multiple mappings because the map
|
|
* management is stack based. The unmap has to be in the reverse order of
|
|
* the map operation:
|
|
*
|
|
* addr1 = kmap_local_page(page1);
|
|
* addr2 = kmap_local_page(page2);
|
|
* ...
|
|
* kunmap_local(addr2);
|
|
* kunmap_local(addr1);
|
|
*
|
|
* Unmapping addr1 before addr2 is invalid and causes malfunction.
|
|
*
|
|
* Contrary to kmap() mappings the mapping is only valid in the context of
|
|
* the caller and cannot be handed to other contexts.
|
|
*
|
|
* On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the
|
|
* virtual address of the direct mapping. Only real highmem pages are
|
|
* temporarily mapped.
|
|
*
|
|
* While it is significantly faster than kmap() for the higmem case it
|
|
* comes with restrictions about the pointer validity. Only use when really
|
|
* necessary.
|
|
*
|
|
* On HIGHMEM enabled systems mapping a highmem page has the side effect of
|
|
* disabling migration in order to keep the virtual address stable across
|
|
* preemption. No caller of kmap_local_page() can rely on this side effect.
|
|
*/
|
|
static inline void *kmap_local_page(struct page *page);
|
|
|
|
/**
|
|
* kmap_atomic - Atomically map a page for temporary usage - Deprecated!
|
|
* @page: Pointer to the page to be mapped
|
|
*
|
|
* Returns: The virtual address of the mapping
|
|
*
|
|
* Effectively a wrapper around kmap_local_page() which disables pagefaults
|
|
* and preemption.
|
|
*
|
|
* Do not use in new code. Use kmap_local_page() instead.
|
|
*/
|
|
static inline void *kmap_atomic(struct page *page);
|
|
|
|
/**
|
|
* kunmap_atomic - Unmap the virtual address mapped by kmap_atomic()
|
|
* @addr: Virtual address to be unmapped
|
|
*
|
|
* Counterpart to kmap_atomic().
|
|
*
|
|
* Effectively a wrapper around kunmap_local() which additionally undoes
|
|
* the side effects of kmap_atomic(), i.e. reenabling pagefaults and
|
|
* preemption.
|
|
*/
|
|
|
|
/* Highmem related interfaces for management code */
|
|
static inline unsigned int nr_free_highpages(void);
|
|
static inline unsigned long totalhigh_pages(void);
|
|
|
|
#ifndef ARCH_HAS_FLUSH_ANON_PAGE
|
|
static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
|
|
static inline void flush_kernel_dcache_page(struct page *page)
|
|
{
|
|
}
|
|
static inline void flush_kernel_vmap_range(void *vaddr, int size)
|
|
{
|
|
}
|
|
static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
|
|
#ifndef clear_user_highpage
|
|
static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
|
|
{
|
|
void *addr = kmap_atomic(page);
|
|
clear_user_page(addr, vaddr, page);
|
|
kunmap_atomic(addr);
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
|
|
/**
|
|
* __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
|
|
* @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
|
|
* @vma: The VMA the page is to be allocated for
|
|
* @vaddr: The virtual address the page will be inserted into
|
|
*
|
|
* This function will allocate a page for a VMA but the caller is expected
|
|
* to specify via movableflags whether the page will be movable in the
|
|
* future or not
|
|
*
|
|
* An architecture may override this function by defining
|
|
* __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
|
|
* implementation.
|
|
*/
|
|
static inline struct page *
|
|
__alloc_zeroed_user_highpage(gfp_t movableflags,
|
|
struct vm_area_struct *vma,
|
|
unsigned long vaddr)
|
|
{
|
|
struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
|
|
vma, vaddr);
|
|
|
|
if (page)
|
|
clear_user_highpage(page, vaddr);
|
|
|
|
return page;
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
|
|
* @vma: The VMA the page is to be allocated for
|
|
* @vaddr: The virtual address the page will be inserted into
|
|
*
|
|
* This function will allocate a page for a VMA that the caller knows will
|
|
* be able to migrate in the future using move_pages() or reclaimed
|
|
*/
|
|
static inline struct page *
|
|
alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
|
|
unsigned long vaddr)
|
|
{
|
|
return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
|
|
}
|
|
|
|
static inline void clear_highpage(struct page *page)
|
|
{
|
|
void *kaddr = kmap_atomic(page);
|
|
clear_page(kaddr);
|
|
kunmap_atomic(kaddr);
|
|
}
|
|
|
|
/*
|
|
* If we pass in a base or tail page, we can zero up to PAGE_SIZE.
|
|
* If we pass in a head page, we can zero up to the size of the compound page.
|
|
*/
|
|
#if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
|
void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
|
|
unsigned start2, unsigned end2);
|
|
#else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
|
|
static inline void zero_user_segments(struct page *page,
|
|
unsigned start1, unsigned end1,
|
|
unsigned start2, unsigned end2)
|
|
{
|
|
void *kaddr = kmap_atomic(page);
|
|
unsigned int i;
|
|
|
|
BUG_ON(end1 > page_size(page) || end2 > page_size(page));
|
|
|
|
if (end1 > start1)
|
|
memset(kaddr + start1, 0, end1 - start1);
|
|
|
|
if (end2 > start2)
|
|
memset(kaddr + start2, 0, end2 - start2);
|
|
|
|
kunmap_atomic(kaddr);
|
|
for (i = 0; i < compound_nr(page); i++)
|
|
flush_dcache_page(page + i);
|
|
}
|
|
#endif /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
|
|
|
|
static inline void zero_user_segment(struct page *page,
|
|
unsigned start, unsigned end)
|
|
{
|
|
zero_user_segments(page, start, end, 0, 0);
|
|
}
|
|
|
|
static inline void zero_user(struct page *page,
|
|
unsigned start, unsigned size)
|
|
{
|
|
zero_user_segments(page, start, start + size, 0, 0);
|
|
}
|
|
|
|
#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
|
|
|
|
static inline void copy_user_highpage(struct page *to, struct page *from,
|
|
unsigned long vaddr, struct vm_area_struct *vma)
|
|
{
|
|
char *vfrom, *vto;
|
|
|
|
vfrom = kmap_atomic(from);
|
|
vto = kmap_atomic(to);
|
|
copy_user_page(vto, vfrom, vaddr, to);
|
|
kunmap_atomic(vto);
|
|
kunmap_atomic(vfrom);
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_COPY_HIGHPAGE
|
|
|
|
static inline void copy_highpage(struct page *to, struct page *from)
|
|
{
|
|
char *vfrom, *vto;
|
|
|
|
vfrom = kmap_atomic(from);
|
|
vto = kmap_atomic(to);
|
|
copy_page(vto, vfrom);
|
|
kunmap_atomic(vto);
|
|
kunmap_atomic(vfrom);
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif /* _LINUX_HIGHMEM_H */
|