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init.c

/*
 *  arch/s390/mm/init.c
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Hartmut Penner (hp@de.ibm.com)
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1995  Linus Torvalds
 */

#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/initrd.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/lowcore.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
char  empty_zero_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

void show_mem(void)
{
      int i, total = 0, reserved = 0;
      int shared = 0, cached = 0;
      struct page *page;

      printk("Mem-info:\n");
      show_free_areas();
      printk("Free swap:       %6ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
      i = max_mapnr;
      while (i-- > 0) {
            if (!pfn_valid(i))
                  continue;
            page = pfn_to_page(i);
            total++;
            if (PageReserved(page))
                  reserved++;
            else if (PageSwapCache(page))
                  cached++;
            else if (page_count(page))
                  shared += page_count(page) - 1;
      }
      printk("%d pages of RAM\n", total);
      printk("%d reserved pages\n", reserved);
      printk("%d pages shared\n", shared);
      printk("%d pages swap cached\n", cached);

      printk("%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
      printk("%lu pages writeback\n", global_page_state(NR_WRITEBACK));
      printk("%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
      printk("%lu pages slab\n",
             global_page_state(NR_SLAB_RECLAIMABLE) +
             global_page_state(NR_SLAB_UNRECLAIMABLE));
      printk("%lu pages pagetables\n", global_page_state(NR_PAGETABLE));
}

static void __init setup_ro_region(void)
{
      pgd_t *pgd;
      pud_t *pud;
      pmd_t *pmd;
      pte_t *pte;
      pte_t new_pte;
      unsigned long address, end;

      address = ((unsigned long)&_stext) & PAGE_MASK;
      end = PFN_ALIGN((unsigned long)&_eshared);

      for (; address < end; address += PAGE_SIZE) {
            pgd = pgd_offset_k(address);
            pud = pud_offset(pgd, address);
            pmd = pmd_offset(pud, address);
            pte = pte_offset_kernel(pmd, address);
            new_pte = mk_pte_phys(address, __pgprot(_PAGE_RO));
            *pte = new_pte;
      }
}

/*
 * paging_init() sets up the page tables
 */
void __init paging_init(void)
{
      static const int ssm_mask = 0x04000000L;
      unsigned long max_zone_pfns[MAX_NR_ZONES];
      unsigned long pgd_type;

      init_mm.pgd = swapper_pg_dir;
      S390_lowcore.kernel_asce = __pa(init_mm.pgd) & PAGE_MASK;
#ifdef CONFIG_64BIT
      S390_lowcore.kernel_asce |= _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
      pgd_type = _REGION3_ENTRY_EMPTY;
#else
      S390_lowcore.kernel_asce |= _ASCE_TABLE_LENGTH;
      pgd_type = _SEGMENT_ENTRY_EMPTY;
#endif
      clear_table((unsigned long *) init_mm.pgd, pgd_type,
                sizeof(unsigned long)*2048);
      vmem_map_init();
      setup_ro_region();

        /* enable virtual mapping in kernel mode */
      __ctl_load(S390_lowcore.kernel_asce, 1, 1);
      __ctl_load(S390_lowcore.kernel_asce, 7, 7);
      __ctl_load(S390_lowcore.kernel_asce, 13, 13);
      __raw_local_irq_ssm(ssm_mask);

      memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_ZONE_DMA
      max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
#endif
      max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
      free_area_init_nodes(max_zone_pfns);
}

void __init mem_init(void)
{
      unsigned long codesize, reservedpages, datasize, initsize;

        max_mapnr = num_physpages = max_low_pfn;
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

        /* clear the zero-page */
        memset(empty_zero_page, 0, PAGE_SIZE);

      /* this will put all low memory onto the freelists */
      totalram_pages += free_all_bootmem();

      reservedpages = 0;

      codesize =  (unsigned long) &_etext - (unsigned long) &_text;
      datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
      initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
        printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
                max_mapnr << (PAGE_SHIFT-10),
                codesize >> 10,
                reservedpages << (PAGE_SHIFT-10),
                datasize >>10,
                initsize >> 10);
      printk("Write protected kernel read-only data: %#lx - %#lx\n",
             (unsigned long)&_stext,
             PFN_ALIGN((unsigned long)&_eshared) - 1);
}

void free_initmem(void)
{
        unsigned long addr;

        addr = (unsigned long)(&__init_begin);
        for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(addr));
            init_page_count(virt_to_page(addr));
            memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
            free_page(addr);
            totalram_pages++;
        }
        printk ("Freeing unused kernel memory: %ldk freed\n",
            ((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
        if (start < end)
                printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
        for (; start < end; start += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                init_page_count(virt_to_page(start));
                free_page(start);
                totalram_pages++;
        }
}
#endif

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