arch/parisc/include/asm/fixmap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_FIXMAP_H
   3 #define _ASM_FIXMAP_H
   4
   5 /*
   6  * This file defines the locations of the fixed mappings on parisc.
   7  *
   8  * All of the values in this file are machine virtual addresses.
   9  *
  10  * All of the values in this file must be <4GB (because of assembly
  11  * loading restrictions).  If you place this region anywhere above
  12  * __PAGE_OFFSET, you must adjust the memory map accordingly
  13  */
  14
  15 /*
  16  * The tmpalias region is used in kernel space to copy/clear/flush data
  17  * from pages congruently mapped with user space. It is comprised of
  18  * a pair regions. The size of these regions is determined by the largest
  19  * cache aliasing boundary for machines that support equivalent aliasing.
  20  *
  21  * The c3750 with PA8700 processor returns an alias value of 11. This
  22  * indicates that it has an alias boundary of 4 MB. It also supports
  23  * non-equivalent aliasing without a performance penalty.
  24  *
  25  * Machines with PA8800/PA8900 processors return an alias value of 0.
  26  * This indicates the alias boundary is unknown and may be larger than
  27  * 16 MB. Non-equivalent aliasing is not supported.
  28  *
  29  * Here we assume the maximum alias boundary is 4 MB.
  30  */
  31 #define TMPALIAS_SIZE_BITS      22      /* 4 MB */
  32 #define TMPALIAS_MAP_START      ((__PAGE_OFFSET) - (2 << TMPALIAS_SIZE_BITS))
  33
  34 #define FIXMAP_SIZE             (FIX_BITMAP_COUNT << PAGE_SHIFT)
  35 #define FIXMAP_START            (TMPALIAS_MAP_START - FIXMAP_SIZE)
  36 /* This is the kernel area for all maps (vmalloc, dma etc.)  most
  37  * usually, it extends up to TMPALIAS_MAP_START.  Virtual addresses
  38  * 0..GATEWAY_PAGE_SIZE are reserved for the gateway page */
  39 #define KERNEL_MAP_START        (GATEWAY_PAGE_SIZE)
  40 #define KERNEL_MAP_END          (FIXMAP_START)
  41
  42 #ifndef __ASSEMBLY__
  43
  44
  45 enum fixed_addresses {
  46         /* Support writing RO kernel text via kprobes, jump labels, etc. */
  47         FIX_TEXT_POKE0,
  48         FIX_TEXT_KEXEC,
  49         FIX_BITMAP_COUNT
  50 };
  51
  52 extern void *parisc_vmalloc_start;
  53 #define PCXL_DMA_MAP_SIZE       (8*1024*1024)
  54 #define VMALLOC_START           ((unsigned long)parisc_vmalloc_start)
  55 #define VMALLOC_END             (KERNEL_MAP_END)
  56
  57 #define __fix_to_virt(_x) (FIXMAP_START + ((_x) << PAGE_SHIFT))
  58
  59 void set_fixmap(enum fixed_addresses idx, phys_addr_t phys);
  60 void clear_fixmap(enum fixed_addresses idx);
  61
  62 #endif /*__ASSEMBLY__*/
  63
  64 #endif /*_ASM_FIXMAP_H*/