include/asm-generic/memory_model.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_MEMORY_MODEL_H
   3 #define __ASM_MEMORY_MODEL_H
   4
   5 #include <linux/pfn.h>
   6
   7 #ifndef __ASSEMBLY__
   8
   9 /*
  10  * supports 3 memory models.
  11  */
  12 #if defined(CONFIG_FLATMEM)
  13
  14 #ifndef ARCH_PFN_OFFSET
  15 #define ARCH_PFN_OFFSET         (0UL)
  16 #endif
  17
  18 #define __pfn_to_page(pfn)      (mem_map + ((pfn) - ARCH_PFN_OFFSET))
  19 #define __page_to_pfn(page)     ((unsigned long)((page) - mem_map) + \
  20                                  ARCH_PFN_OFFSET)
  21
  22 #ifndef pfn_valid
  23 static inline int pfn_valid(unsigned long pfn)
  24 {
  25         /* avoid <linux/mm.h> include hell */
  26         extern unsigned long max_mapnr;
  27         unsigned long pfn_offset = ARCH_PFN_OFFSET;
  28
  29         return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
  30 }
  31 #define pfn_valid pfn_valid
  32 #endif
  33
  34 #elif defined(CONFIG_SPARSEMEM_VMEMMAP)
  35
  36 /* memmap is virtually contiguous.  */
  37 #define __pfn_to_page(pfn)      (vmemmap + (pfn))
  38 #define __page_to_pfn(page)     (unsigned long)((page) - vmemmap)
  39
  40 #elif defined(CONFIG_SPARSEMEM)
  41 /*
  42  * Note: section's mem_map is encoded to reflect its start_pfn.
  43  * section[i].section_mem_map == mem_map's address - start_pfn;
  44  */
  45 #define __page_to_pfn(pg)                                       \
  46 ({      const struct page *__pg = (pg);                         \
  47         int __sec = page_to_section(__pg);                      \
  48         (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
  49 })
  50
  51 #define __pfn_to_page(pfn)                              \
  52 ({      unsigned long __pfn = (pfn);                    \
  53         struct mem_section *__sec = __pfn_to_section(__pfn);    \
  54         __section_mem_map_addr(__sec) + __pfn;          \
  55 })
  56 #endif /* CONFIG_FLATMEM/SPARSEMEM */
  57
  58 /*
  59  * Convert a physical address to a Page Frame Number and back
  60  */
  61 #define __phys_to_pfn(paddr)    PHYS_PFN(paddr)
  62 #define __pfn_to_phys(pfn)      PFN_PHYS(pfn)
  63
  64 #define page_to_pfn __page_to_pfn
  65 #define pfn_to_page __pfn_to_page
  66
  67 #ifdef CONFIG_DEBUG_VIRTUAL
  68 #define page_to_phys(page)                                              \
  69 ({                                                                      \
  70         unsigned long __pfn = page_to_pfn(page);                        \
  71                                                                         \
  72         WARN_ON_ONCE(!pfn_valid(__pfn));                                \
  73         PFN_PHYS(__pfn);                                                \
  74 })
  75 #else
  76 #define page_to_phys(page)      PFN_PHYS(page_to_pfn(page))
  77 #endif /* CONFIG_DEBUG_VIRTUAL */
  78 #define phys_to_page(phys)      pfn_to_page(PHYS_PFN(phys))
  79
  80 #endif /* __ASSEMBLY__ */
  81
  82 #endif