LXR linux/arch/metag/include/asm/highmem.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_HIGHMEM_H
   3#define _ASM_HIGHMEM_H
   4
   5#include <asm/cacheflush.h>
   6#include <asm/kmap_types.h>
   7#include <asm/fixmap.h>
   8
   9/*
  10 * Right now we initialize only a single pte table. It can be extended
  11 * easily, subsequent pte tables have to be allocated in one physical
  12 * chunk of RAM.
  13 */
  14/*
  15 * Ordering is (from lower to higher memory addresses):
  16 *
  17 * high_memory
  18 *                      Persistent kmap area
  19 * PKMAP_BASE
  20 *                      fixed_addresses
  21 * FIXADDR_START
  22 * FIXADDR_TOP
  23 *                      Vmalloc area
  24 * VMALLOC_START
  25 * VMALLOC_END
  26 */
  27#define PKMAP_BASE              (FIXADDR_START - PMD_SIZE)
  28#define LAST_PKMAP              PTRS_PER_PTE
  29#define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  30#define PKMAP_NR(virt)          (((virt) - PKMAP_BASE) >> PAGE_SHIFT)
  31#define PKMAP_ADDR(nr)          (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  32
  33#define kmap_prot               PAGE_KERNEL
  34
  35static inline void flush_cache_kmaps(void)
  36{
  37        flush_cache_all();
  38}
  39
  40/* declarations for highmem.c */
  41extern unsigned long highstart_pfn, highend_pfn;
  42
  43extern pte_t *pkmap_page_table;
  44
  45extern void *kmap_high(struct page *page);
  46extern void kunmap_high(struct page *page);
  47
  48extern void kmap_init(void);
  49
  50/*
  51 * The following functions are already defined by <linux/highmem.h>
  52 * when CONFIG_HIGHMEM is not set.
  53 */
  54#ifdef CONFIG_HIGHMEM
  55extern void *kmap(struct page *page);
  56extern void kunmap(struct page *page);
  57extern void *kmap_atomic(struct page *page);
  58extern void __kunmap_atomic(void *kvaddr);
  59extern void *kmap_atomic_pfn(unsigned long pfn);
  60#endif
  61
  62#endif
  63