arch/s390/mm/mem_detect.c

   1 /*
   2  * Copyright IBM Corp. 2008, 2009
   3  *
   4  * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <asm/ipl.h>
  10 #include <asm/sclp.h>
  11 #include <asm/setup.h>
  12
  13 #define ADDR2G (1ULL << 31)
  14
  15 static void find_memory_chunks(struct mem_chunk chunk[], unsigned long maxsize)
  16 {
  17         unsigned long long memsize, rnmax, rzm;
  18         unsigned long addr = 0, size;
  19         int i = 0, type;
  20
  21         rzm = sclp_get_rzm();
  22         rnmax = sclp_get_rnmax();
  23         memsize = rzm * rnmax;
  24         if (!rzm)
  25                 rzm = 1ULL << 17;
  26         if (sizeof(long) == 4) {
  27                 rzm = min(ADDR2G, rzm);
  28                 memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
  29         }
  30         if (maxsize)
  31                 memsize = memsize ? min((unsigned long)memsize, maxsize) : maxsize;
  32         do {
  33                 size = 0;
  34                 type = tprot(addr);
  35                 do {
  36                         size += rzm;
  37                         if (memsize && addr + size >= memsize)
  38                                 break;
  39                 } while (type == tprot(addr + size));
  40                 if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
  41                         if (memsize && (addr + size > memsize))
  42                                 size = memsize - addr;
  43                         chunk[i].addr = addr;
  44                         chunk[i].size = size;
  45                         chunk[i].type = type;
  46                         i++;
  47                 }
  48                 addr += size;
  49         } while (addr < memsize && i < MEMORY_CHUNKS);
  50 }
  51
  52 /**
  53  * detect_memory_layout - fill mem_chunk array with memory layout data
  54  * @chunk: mem_chunk array to be filled
  55  * @maxsize: maximum address where memory detection should stop
  56  *
  57  * Fills the passed in memory chunk array with the memory layout of the
  58  * machine. The array must have a size of at least MEMORY_CHUNKS and will
  59  * be fully initialized afterwards.
  60  * If the maxsize paramater has a value > 0 memory detection will stop at
  61  * that address. It is guaranteed that all chunks have an ending address
  62  * that is smaller than maxsize.
  63  * If maxsize is 0 all memory will be detected.
  64  */
  65 void detect_memory_layout(struct mem_chunk chunk[], unsigned long maxsize)
  66 {
  67         unsigned long flags, flags_dat, cr0;
  68
  69         memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
  70         /*
  71          * Disable IRQs, DAT and low address protection so tprot does the
  72          * right thing and we don't get scheduled away with low address
  73          * protection disabled.
  74          */
  75         local_irq_save(flags);
  76         flags_dat = __arch_local_irq_stnsm(0xfb);
  77         /*
  78          * In case DAT was enabled, make sure chunk doesn't reside in vmalloc
  79          * space. We have disabled DAT and any access to vmalloc area will
  80          * cause an exception.
  81          * If DAT was disabled we are called from early ipl code.
  82          */
  83         if (test_bit(5, &flags_dat)) {
  84                 if (WARN_ON_ONCE(is_vmalloc_or_module_addr(chunk)))
  85                         goto out;
  86         }
  87         __ctl_store(cr0, 0, 0);
  88         __ctl_clear_bit(0, 28);
  89         find_memory_chunks(chunk, maxsize);
  90         __ctl_load(cr0, 0, 0);
  91 out:
  92         __arch_local_irq_ssm(flags_dat);
  93         local_irq_restore(flags);
  94 }
  95 EXPORT_SYMBOL(detect_memory_layout);
  96
  97 /*
  98  * Create memory hole with given address and size.
  99  */
 100 void create_mem_hole(struct mem_chunk mem_chunk[], unsigned long addr,
 101                      unsigned long size)
 102 {
 103         int i;
 104
 105         for (i = 0; i < MEMORY_CHUNKS; i++) {
 106                 struct mem_chunk *chunk = &mem_chunk[i];
 107
 108                 if (chunk->size == 0)
 109                         continue;
 110                 if (addr > chunk->addr + chunk->size)
 111                         continue;
 112                 if (addr + size <= chunk->addr)
 113                         continue;
 114                 /* Split */
 115                 if ((addr > chunk->addr) &&
 116                     (addr + size < chunk->addr + chunk->size)) {
 117                         struct mem_chunk *new = chunk + 1;
 118
 119                         memmove(new, chunk, (MEMORY_CHUNKS-i-1) * sizeof(*new));
 120                         new->addr = addr + size;
 121                         new->size = chunk->addr + chunk->size - new->addr;
 122                         chunk->size = addr - chunk->addr;
 123                         continue;
 124                 } else if ((addr <= chunk->addr) &&
 125                            (addr + size >= chunk->addr + chunk->size)) {
 126                         memset(chunk, 0 , sizeof(*chunk));
 127                 } else if (addr + size < chunk->addr + chunk->size) {
 128                         chunk->size =  chunk->addr + chunk->size - addr - size;
 129                         chunk->addr = addr + size;
 130                 } else if (addr > chunk->addr) {
 131                         chunk->size = addr - chunk->addr;
 132                 }
 133         }
 134 }