arch/s390/include/asm/mem_detect.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_S390_MEM_DETECT_H
   3 #define _ASM_S390_MEM_DETECT_H
   4
   5 #include <linux/types.h>
   6
   7 enum mem_info_source {
   8         MEM_DETECT_NONE = 0,
   9         MEM_DETECT_SCLP_STOR_INFO,
  10         MEM_DETECT_DIAG260,
  11         MEM_DETECT_SCLP_READ_INFO,
  12         MEM_DETECT_BIN_SEARCH
  13 };
  14
  15 struct mem_detect_block {
  16         u64 start;
  17         u64 end;
  18 };
  19
  20 /*
  21  * Storage element id is defined as 1 byte (up to 256 storage elements).
  22  * In practise only storage element id 0 and 1 are used).
  23  * According to architecture one storage element could have as much as
  24  * 1020 subincrements. 255 mem_detect_blocks are embedded in mem_detect_info.
  25  * If more mem_detect_blocks are required, a block of memory from already
  26  * known mem_detect_block is taken (entries_extended points to it).
  27  */
  28 #define MEM_INLINED_ENTRIES 255 /* (PAGE_SIZE - 16) / 16 */
  29
  30 struct mem_detect_info {
  31         u32 count;
  32         u8 info_source;
  33         struct mem_detect_block entries[MEM_INLINED_ENTRIES];
  34         struct mem_detect_block *entries_extended;
  35 };
  36 extern struct mem_detect_info mem_detect;
  37
  38 void add_mem_detect_block(u64 start, u64 end);
  39
  40 static inline int __get_mem_detect_block(u32 n, unsigned long *start,
  41                                          unsigned long *end)
  42 {
  43         if (n >= mem_detect.count) {
  44                 *start = 0;
  45                 *end = 0;
  46                 return -1;
  47         }
  48
  49         if (n < MEM_INLINED_ENTRIES) {
  50                 *start = (unsigned long)mem_detect.entries[n].start;
  51                 *end = (unsigned long)mem_detect.entries[n].end;
  52         } else {
  53                 *start = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].start;
  54                 *end = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].end;
  55         }
  56         return 0;
  57 }
  58
  59 /**
  60  * for_each_mem_detect_block - early online memory range iterator
  61  * @i: an integer used as loop variable
  62  * @p_start: ptr to unsigned long for start address of the range
  63  * @p_end: ptr to unsigned long for end address of the range
  64  *
  65  * Walks over detected online memory ranges.
  66  */
  67 #define for_each_mem_detect_block(i, p_start, p_end)                    \
  68         for (i = 0, __get_mem_detect_block(i, p_start, p_end);          \
  69              i < mem_detect.count;                                      \
  70              i++, __get_mem_detect_block(i, p_start, p_end))
  71
  72 static inline void get_mem_detect_reserved(unsigned long *start,
  73                                            unsigned long *size)
  74 {
  75         *start = (unsigned long)mem_detect.entries_extended;
  76         if (mem_detect.count > MEM_INLINED_ENTRIES)
  77                 *size = (mem_detect.count - MEM_INLINED_ENTRIES) * sizeof(struct mem_detect_block);
  78         else
  79                 *size = 0;
  80 }
  81
  82 static inline unsigned long get_mem_detect_end(void)
  83 {
  84         unsigned long start;
  85         unsigned long end;
  86
  87         if (mem_detect.count) {
  88                 __get_mem_detect_block(mem_detect.count - 1, &start, &end);
  89                 return end;
  90         }
  91         return 0;
  92 }
  93
  94 #endif