arch/x86/include/asm/page_32_types.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_PAGE_32_DEFS_H
   3 #define _ASM_X86_PAGE_32_DEFS_H
   4
   5 #include <linux/const.h>
   6
   7 /*
   8  * This handles the memory map.
   9  *
  10  * A __PAGE_OFFSET of 0xC0000000 means that the kernel has
  11  * a virtual address space of one gigabyte, which limits the
  12  * amount of physical memory you can use to about 950MB.
  13  *
  14  * If you want more physical memory than this then see the CONFIG_HIGHMEM4G
  15  * and CONFIG_HIGHMEM64G options in the kernel configuration.
  16  */
  17 #define __PAGE_OFFSET_BASE      _AC(CONFIG_PAGE_OFFSET, UL)
  18 #define __PAGE_OFFSET           __PAGE_OFFSET_BASE
  19
  20 #define __START_KERNEL_map      __PAGE_OFFSET
  21
  22 #define THREAD_SIZE_ORDER       1
  23 #define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)
  24
  25 #define IRQ_STACK_SIZE          THREAD_SIZE
  26
  27 #define N_EXCEPTION_STACKS      1
  28
  29 #ifdef CONFIG_X86_PAE
  30 /*
  31  * This is beyond the 44 bit limit imposed by the 32bit long pfns,
  32  * but we need the full mask to make sure inverted PROT_NONE
  33  * entries have all the host bits set in a guest.
  34  * The real limit is still 44 bits.
  35  */
  36 #define __PHYSICAL_MASK_SHIFT   52
  37 #define __VIRTUAL_MASK_SHIFT    32
  38
  39 #else  /* !CONFIG_X86_PAE */
  40 #define __PHYSICAL_MASK_SHIFT   32
  41 #define __VIRTUAL_MASK_SHIFT    32
  42 #endif  /* CONFIG_X86_PAE */
  43
  44 /*
  45  * Kernel image size is limited to 512 MB (see in arch/x86/kernel/head_32.S)
  46  */
  47 #define KERNEL_IMAGE_SIZE       (512 * 1024 * 1024)
  48
  49 #ifndef __ASSEMBLY__
  50
  51 /*
  52  * This much address space is reserved for vmalloc() and iomap()
  53  * as well as fixmap mappings.
  54  */
  55 extern unsigned int __VMALLOC_RESERVE;
  56 extern int sysctl_legacy_va_layout;
  57
  58 extern void find_low_pfn_range(void);
  59 extern void setup_bootmem_allocator(void);
  60
  61 #endif  /* !__ASSEMBLY__ */
  62
  63 #endif /* _ASM_X86_PAGE_32_DEFS_H */