arch/powerpc/include/asm/highmem.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * highmem.h: virtual kernel memory mappings for high memory
   4  *
   5  * PowerPC version, stolen from the i386 version.
   6  *
   7  * Used in CONFIG_HIGHMEM systems for memory pages which
   8  * are not addressable by direct kernel virtual addresses.
   9  *
  10  * Copyright (C) 1999 Gerhard Wichert, Siemens AG
  11  *                    Gerhard.Wichert@pdb.siemens.de
  12  *
  13  *
  14  * Redesigned the x86 32-bit VM architecture to deal with
  15  * up to 16 Terrabyte physical memory. With current x86 CPUs
  16  * we now support up to 64 Gigabytes physical RAM.
  17  *
  18  * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
  19  */
  20
  21 #ifndef _ASM_HIGHMEM_H
  22 #define _ASM_HIGHMEM_H
  23
  24 #ifdef __KERNEL__
  25
  26 #include <linux/interrupt.h>
  27 #include <asm/cacheflush.h>
  28 #include <asm/page.h>
  29 #include <asm/fixmap.h>
  30
  31 extern pte_t *pkmap_page_table;
  32
  33 /*
  34  * Right now we initialize only a single pte table. It can be extended
  35  * easily, subsequent pte tables have to be allocated in one physical
  36  * chunk of RAM.
  37  */
  38 /*
  39  * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
  40  * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
  41  * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
  42  * in case of 16K/64K/256K page sizes.
  43  */
  44 #ifdef CONFIG_PPC_4K_PAGES
  45 #define PKMAP_ORDER     PTE_SHIFT
  46 #else
  47 #define PKMAP_ORDER     9
  48 #endif
  49 #define LAST_PKMAP      (1 << PKMAP_ORDER)
  50 #ifndef CONFIG_PPC_4K_PAGES
  51 #define PKMAP_BASE      (FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1))
  52 #else
  53 #define PKMAP_BASE      ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK)
  54 #endif
  55 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
  56 #define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
  57 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  58
  59 #define flush_cache_kmaps()     flush_cache_all()
  60
  61 #define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev)  \
  62         __set_pte_at(mm, vaddr, ptep, ptev, 1)
  63 #define arch_kmap_local_post_map(vaddr, pteval) \
  64         local_flush_tlb_page(NULL, vaddr)
  65 #define arch_kmap_local_post_unmap(vaddr)       \
  66         local_flush_tlb_page(NULL, vaddr)
  67
  68 #endif /* __KERNEL__ */
  69
  70 #endif /* _ASM_HIGHMEM_H */