LXR linux/arch/s390/kernel/mem

   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
  15static void find_memory_chunks(struct mem_chunk chunk[])
  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        do {
  31                size = 0;
  32                type = tprot(addr);
  33                do {
  34                        size += rzm;
  35                        if (memsize && addr + size >= memsize)
  36                                break;
  37                } while (type == tprot(addr + size));
  38                if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
  39                        chunk[i].addr = addr;
  40                        chunk[i].size = size;
  41                        chunk[i].type = type;
  42                        i++;
  43                }
  44                addr += size;
  45        } while (addr < memsize && i < MEMORY_CHUNKS);
  46}
  47
  48void detect_memory_layout(struct mem_chunk chunk[])
  49{
  50        unsigned long flags, cr0;
  51
  52        memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
  53        /* Disable IRQs, DAT and low address protection so tprot does the
  54         * right thing and we don't get scheduled away with low address
  55         * protection disabled.
  56         */
  57        flags = __raw_local_irq_stnsm(0xf8);
  58        __ctl_store(cr0, 0, 0);
  59        __ctl_clear_bit(0, 28);
  60        find_memory_chunks(chunk);
  61        __ctl_load(cr0, 0, 0);
  62        __raw_local_irq_ssm(flags);
  63}
  64EXPORT_SYMBOL(detect_memory_layout);
  65