/*
   *  S390 version
   *    Copyright IBM Corp. 1999
   *    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/memory.h>
  #include <linux/pfn.h>
  #include <linux/poison.h>
  #include <linux/initrd.h>
  #include <linux/export.h>
  #include <linux/gfp.h>
  #include <asm/processor.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>
  #include <asm/ctl_reg.h>
  #include <asm/sclp.h>
  
  pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
  
  unsigned long empty_zero_page, zero_page_mask;
  EXPORT_SYMBOL(empty_zero_page);
  
  static void __init setup_zero_pages(void)
  {
  	struct cpuid cpu_id;
  	unsigned int order;
  	struct page *page;
  	int i;
  
  	get_cpu_id(&cpu_id);
  	switch (cpu_id.machine) {
  	case 0x9672:	/* g5 */
  	case 0x2064:	/* z900 */
  	case 0x2066:	/* z900 */
  	case 0x2084:	/* z990 */
  	case 0x2086:	/* z990 */
  	case 0x2094:	/* z9-109 */
  	case 0x2096:	/* z9-109 */
  		order = 0;
  		break;
  	case 0x2097:	/* z10 */
  	case 0x2098:	/* z10 */
  	case 0x2817:	/* z196 */
  	case 0x2818:	/* z196 */
  		order = 2;
  		break;
  	case 0x2827:	/* zEC12 */
  	case 0x2828:	/* zEC12 */
  	default:
  		order = 5;
  		break;
  	}
  	/* Limit number of empty zero pages for small memory sizes */
  	if (order > 2 && totalram_pages <= 16384)
  		order = 2;
  
  	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
  	if (!empty_zero_page)
  		panic("Out of memory in setup_zero_pages");
  
  	page = virt_to_page((void *) empty_zero_page);
  	split_page(page, order);
  	for (i = 1 << order; i > 0; i--) {
  		mark_page_reserved(page);
  		page++;
  	}
  
  	zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
  }
  
  /*
   * paging_init() sets up the page tables
   */
  void __init paging_init(void)
  {
  	unsigned long max_zone_pfns[MAX_NR_ZONES];
  	unsigned long pgd_type, asce_bits;
  
  	init_mm.pgd = swapper_pg_dir;
  #ifdef CONFIG_64BIT
  	if (VMALLOC_END > (1UL << 42)) {
  		asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
  		pgd_type = _REGION2_ENTRY_EMPTY;
  	} else {
  		asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
  		pgd_type = _REGION3_ENTRY_EMPTY;
  	}
  #else
  	asce_bits = _ASCE_TABLE_LENGTH;
  	pgd_type = _SEGMENT_ENTRY_EMPTY;
  #endif
  	S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
  	clear_table((unsigned long *) init_mm.pgd, pgd_type,
  		    sizeof(unsigned long)*2048);
  	vmem_map_init();
  
          /* 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);
  	arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));
  
  	atomic_set(&init_mm.context.attach_count, 1);
  
  	sparse_memory_present_with_active_regions(MAX_NUMNODES);
  	sparse_init();
  	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
  	max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
  	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
  	free_area_init_nodes(max_zone_pfns);
  }
  
  void __init mem_init(void)
  {
          max_mapnr = max_low_pfn;
          high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
  
  	/* Setup guest page hinting */
  	cmma_init();
  
  	/* this will put all low memory onto the freelists */
  	free_all_bootmem();
  	setup_zero_pages();	/* Setup zeroed pages. */
  
  	mem_init_print_info(NULL);
  	printk("Write protected kernel read-only data: %#lx - %#lx
  ",
  	       (unsigned long)&_stext,
  	       PFN_ALIGN((unsigned long)&_eshared) - 1);
  }
  
  void free_initmem(void)
  {
  	free_initmem_default(POISON_FREE_INITMEM);
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  void __init free_initrd_mem(unsigned long start, unsigned long end)
  {
  	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
  			   "initrd");
  }
  #endif
  
  #ifdef CONFIG_MEMORY_HOTPLUG
  int arch_add_memory(int nid, u64 start, u64 size)
  {
  	unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
  	unsigned long start_pfn = PFN_DOWN(start);
  	unsigned long size_pages = PFN_DOWN(size);
  	struct zone *zone;
  	int rc;
  
  	rc = vmem_add_mapping(start, size);
  	if (rc)
  		return rc;
  	for_each_zone(zone) {
  		if (zone_idx(zone) != ZONE_MOVABLE) {
  			/* Add range within existing zone limits */
  			zone_start_pfn = zone->zone_start_pfn;
  			zone_end_pfn = zone->zone_start_pfn +
  				       zone->spanned_pages;
  		} else {
  			/* Add remaining range to ZONE_MOVABLE */
  			zone_start_pfn = start_pfn;
  			zone_end_pfn = start_pfn + size_pages;
  		}
  		if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
  			continue;
  		nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
  			   zone_end_pfn - start_pfn : size_pages;
  		rc = __add_pages(nid, zone, start_pfn, nr_pages);
  		if (rc)
  			break;
  		start_pfn += nr_pages;
  		size_pages -= nr_pages;
  		if (!size_pages)
  			break;
  	}
  	if (rc)
  		vmem_remove_mapping(start, size);
  	return rc;
  }
  
  unsigned long memory_block_size_bytes(void)
  {
  	/*
  	 * Make sure the memory block size is always greater
  	 * or equal than the memory increment size.
  	 */
  	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp_get_rzm());
  }
  
  #ifdef CONFIG_MEMORY_HOTREMOVE
  int arch_remove_memory(u64 start, u64 size)
  {
  	/*
  	 * There is no hardware or firmware interface which could trigger a
  	 * hot memory remove on s390. So there is nothing that needs to be
  	 * implemented.
  	 */
  	return -EBUSY;
  }
  #endif
  #endif /* CONFIG_MEMORY_HOTPLUG */