arch/x86/mm/physaddr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/memblock.h>
   3 #include <linux/mmdebug.h>
   4 #include <linux/export.h>
   5 #include <linux/mm.h>
   6
   7 #include <asm/page.h>
   8
   9 #include "physaddr.h"
  10
  11 #ifdef CONFIG_X86_64
  12
  13 #ifdef CONFIG_DEBUG_VIRTUAL
  14 unsigned long __phys_addr(unsigned long x)
  15 {
  16         unsigned long y = x - __START_KERNEL_map;
  17
  18         /* use the carry flag to determine if x was < __START_KERNEL_map */
  19         if (unlikely(x > y)) {
  20                 x = y + phys_base;
  21
  22                 VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
  23         } else {
  24                 x = y + (__START_KERNEL_map - PAGE_OFFSET);
  25
  26                 /* carry flag will be set if starting x was >= PAGE_OFFSET */
  27                 VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
  28         }
  29
  30         return x;
  31 }
  32 EXPORT_SYMBOL(__phys_addr);
  33
  34 unsigned long __phys_addr_symbol(unsigned long x)
  35 {
  36         unsigned long y = x - __START_KERNEL_map;
  37
  38         /* only check upper bounds since lower bounds will trigger carry */
  39         VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
  40
  41         return y + phys_base;
  42 }
  43 EXPORT_SYMBOL(__phys_addr_symbol);
  44 #endif
  45
  46 bool __virt_addr_valid(unsigned long x)
  47 {
  48         unsigned long y = x - __START_KERNEL_map;
  49
  50         /* use the carry flag to determine if x was < __START_KERNEL_map */
  51         if (unlikely(x > y)) {
  52                 x = y + phys_base;
  53
  54                 if (y >= KERNEL_IMAGE_SIZE)
  55                         return false;
  56         } else {
  57                 x = y + (__START_KERNEL_map - PAGE_OFFSET);
  58
  59                 /* carry flag will be set if starting x was >= PAGE_OFFSET */
  60                 if ((x > y) || !phys_addr_valid(x))
  61                         return false;
  62         }
  63
  64         return pfn_valid(x >> PAGE_SHIFT);
  65 }
  66 EXPORT_SYMBOL(__virt_addr_valid);
  67
  68 #else
  69
  70 #ifdef CONFIG_DEBUG_VIRTUAL
  71 unsigned long __phys_addr(unsigned long x)
  72 {
  73         unsigned long phys_addr = x - PAGE_OFFSET;
  74         /* VMALLOC_* aren't constants  */
  75         VIRTUAL_BUG_ON(x < PAGE_OFFSET);
  76         VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
  77         /* max_low_pfn is set early, but not _that_ early */
  78         if (max_low_pfn) {
  79                 VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
  80                 BUG_ON(slow_virt_to_phys((void *)x) != phys_addr);
  81         }
  82         return phys_addr;
  83 }
  84 EXPORT_SYMBOL(__phys_addr);
  85 #endif
  86
  87 bool __virt_addr_valid(unsigned long x)
  88 {
  89         if (x < PAGE_OFFSET)
  90                 return false;
  91         if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
  92                 return false;
  93         if (x >= FIXADDR_START)
  94                 return false;
  95         return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
  96 }
  97 EXPORT_SYMBOL(__virt_addr_valid);
  98
  99 #endif  /* CONFIG_X86_64 */