linux-stable/arch/x86/include/asm/pgtable_32_areas.h
Ingo Molnar 186525bd6b mm, x86/mm: Untangle address space layout definitions from basic pgtable type definitions
- Untangle the somewhat incestous way of how VMALLOC_START is used all across the
  kernel, but is, on x86, defined deep inside one of the lowest level page table headers.
  It doesn't help that vmalloc.h only includes a single asm header:

     #include <asm/page.h>           /* pgprot_t */

  So there was no existing cross-arch way to decouple address layout
  definitions from page.h details. I used this:

   #ifndef VMALLOC_START
   # include <asm/vmalloc.h>
   #endif

  This way every architecture that wants to simplify page.h can do so.

- Also on x86 we had a couple of LDT related inline functions that used
  the late-stage address space layout positions - but these could be
  uninlined without real trouble - the end result is cleaner this way as
  well.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-10 10:12:55 +01:00

53 lines
1.5 KiB
C

#ifndef _ASM_X86_PGTABLE_32_AREAS_H
#define _ASM_X86_PGTABLE_32_AREAS_H
#include <asm/cpu_entry_area.h>
/*
* Just any arbitrary offset to the start of the vmalloc VM area: the
* current 8MB value just means that there will be a 8MB "hole" after the
* physical memory until the kernel virtual memory starts. That means that
* any out-of-bounds memory accesses will hopefully be caught.
* The vmalloc() routines leaves a hole of 4kB between each vmalloced
* area for the same reason. ;)
*/
#define VMALLOC_OFFSET (8 * 1024 * 1024)
#ifndef __ASSEMBLY__
extern bool __vmalloc_start_set; /* set once high_memory is set */
#endif
#define VMALLOC_START ((unsigned long)high_memory + VMALLOC_OFFSET)
#ifdef CONFIG_X86_PAE
#define LAST_PKMAP 512
#else
#define LAST_PKMAP 1024
#endif
#define CPU_ENTRY_AREA_PAGES (NR_CPUS * DIV_ROUND_UP(sizeof(struct cpu_entry_area), PAGE_SIZE))
/* The +1 is for the readonly IDT page: */
#define CPU_ENTRY_AREA_BASE \
((FIXADDR_TOT_START - PAGE_SIZE*(CPU_ENTRY_AREA_PAGES+1)) & PMD_MASK)
#define LDT_BASE_ADDR \
((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)
#define LDT_END_ADDR (LDT_BASE_ADDR + PMD_SIZE)
#define PKMAP_BASE \
((LDT_BASE_ADDR - PAGE_SIZE) & PMD_MASK)
#ifdef CONFIG_HIGHMEM
# define VMALLOC_END (PKMAP_BASE - 2 * PAGE_SIZE)
#else
# define VMALLOC_END (LDT_BASE_ADDR - 2 * PAGE_SIZE)
#endif
#define MODULES_VADDR VMALLOC_START
#define MODULES_END VMALLOC_END
#define MODULES_LEN (MODULES_VADDR - MODULES_END)
#define MAXMEM (VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)
#endif /* _ASM_X86_PGTABLE_32_AREAS_H */