linux/arch/x86/mm/physaddr.c
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

101 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/memblock.h>
#include <linux/mmdebug.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <linux/vmalloc.h>
#include "physaddr.h"
#ifdef CONFIG_X86_64
#ifdef CONFIG_DEBUG_VIRTUAL
unsigned long __phys_addr(unsigned long x)
{
unsigned long y = x - __START_KERNEL_map;
/* use the carry flag to determine if x was < __START_KERNEL_map */
if (unlikely(x > y)) {
x = y + phys_base;
VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
} else {
x = y + (__START_KERNEL_map - PAGE_OFFSET);
/* carry flag will be set if starting x was >= PAGE_OFFSET */
VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
}
return x;
}
EXPORT_SYMBOL(__phys_addr);
unsigned long __phys_addr_symbol(unsigned long x)
{
unsigned long y = x - __START_KERNEL_map;
/* only check upper bounds since lower bounds will trigger carry */
VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
return y + phys_base;
}
EXPORT_SYMBOL(__phys_addr_symbol);
#endif
bool __virt_addr_valid(unsigned long x)
{
unsigned long y = x - __START_KERNEL_map;
/* use the carry flag to determine if x was < __START_KERNEL_map */
if (unlikely(x > y)) {
x = y + phys_base;
if (y >= KERNEL_IMAGE_SIZE)
return false;
} else {
x = y + (__START_KERNEL_map - PAGE_OFFSET);
/* carry flag will be set if starting x was >= PAGE_OFFSET */
if ((x > y) || !phys_addr_valid(x))
return false;
}
return pfn_valid(x >> PAGE_SHIFT);
}
EXPORT_SYMBOL(__virt_addr_valid);
#else
#ifdef CONFIG_DEBUG_VIRTUAL
unsigned long __phys_addr(unsigned long x)
{
unsigned long phys_addr = x - PAGE_OFFSET;
/* VMALLOC_* aren't constants */
VIRTUAL_BUG_ON(x < PAGE_OFFSET);
VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
/* max_low_pfn is set early, but not _that_ early */
if (max_low_pfn) {
VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
BUG_ON(slow_virt_to_phys((void *)x) != phys_addr);
}
return phys_addr;
}
EXPORT_SYMBOL(__phys_addr);
#endif
bool __virt_addr_valid(unsigned long x)
{
if (x < PAGE_OFFSET)
return false;
if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
return false;
if (x >= FIXADDR_START)
return false;
return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
}
EXPORT_SYMBOL(__virt_addr_valid);
#endif /* CONFIG_X86_64 */