x86/mm/physaddr.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/memblock.h>
0003 #include <linux/mmdebug.h>
0004 #include <linux/export.h>
0005 #include <linux/mm.h>
0006
0007 #include <asm/page.h>
0008 #include <linux/vmalloc.h>
0009
0010 #include "physaddr.h"
0011
0012 #ifdef CONFIG_X86_64
0013
0014 #ifdef CONFIG_DEBUG_VIRTUAL
0015 unsigned long __phys_addr(unsigned long x)
0016 {
0017     unsigned long y = x - __START_KERNEL_map;
0018
0019     /* use the carry flag to determine if x was < __START_KERNEL_map */
0020     if (unlikely(x > y)) {
0021         x = y + phys_base;
0022
0023         VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
0024     } else {
0025         x = y + (__START_KERNEL_map - PAGE_OFFSET);
0026
0027         /* carry flag will be set if starting x was >= PAGE_OFFSET */
0028         VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
0029     }
0030
0031     return x;
0032 }
0033 EXPORT_SYMBOL(__phys_addr);
0034
0035 unsigned long __phys_addr_symbol(unsigned long x)
0036 {
0037     unsigned long y = x - __START_KERNEL_map;
0038
0039     /* only check upper bounds since lower bounds will trigger carry */
0040     VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
0041
0042     return y + phys_base;
0043 }
0044 EXPORT_SYMBOL(__phys_addr_symbol);
0045 #endif
0046
0047 bool __virt_addr_valid(unsigned long x)
0048 {
0049     unsigned long y = x - __START_KERNEL_map;
0050
0051     /* use the carry flag to determine if x was < __START_KERNEL_map */
0052     if (unlikely(x > y)) {
0053         x = y + phys_base;
0054
0055         if (y >= KERNEL_IMAGE_SIZE)
0056             return false;
0057     } else {
0058         x = y + (__START_KERNEL_map - PAGE_OFFSET);
0059
0060         /* carry flag will be set if starting x was >= PAGE_OFFSET */
0061         if ((x > y) || !phys_addr_valid(x))
0062             return false;
0063     }
0064
0065     return pfn_valid(x >> PAGE_SHIFT);
0066 }
0067 EXPORT_SYMBOL(__virt_addr_valid);
0068
0069 #else
0070
0071 #ifdef CONFIG_DEBUG_VIRTUAL
0072 unsigned long __phys_addr(unsigned long x)
0073 {
0074     unsigned long phys_addr = x - PAGE_OFFSET;
0075     /* VMALLOC_* aren't constants  */
0076     VIRTUAL_BUG_ON(x < PAGE_OFFSET);
0077     VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
0078     /* max_low_pfn is set early, but not _that_ early */
0079     if (max_low_pfn) {
0080         VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
0081         BUG_ON(slow_virt_to_phys((void *)x) != phys_addr);
0082     }
0083     return phys_addr;
0084 }
0085 EXPORT_SYMBOL(__phys_addr);
0086 #endif
0087
0088 bool __virt_addr_valid(unsigned long x)
0089 {
0090     if (x < PAGE_OFFSET)
0091         return false;
0092     if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
0093         return false;
0094     if (x >= FIXADDR_START)
0095         return false;
0096     return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
0097 }
0098 EXPORT_SYMBOL(__virt_addr_valid);
0099
0100 #endif  /* CONFIG_X86_64 */