arch/s390/mm/init.c

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 1999
   4  *    Author(s): Hartmut Penner (hp@de.ibm.com)
   5  *
   6  *  Derived from "arch/i386/mm/init.c"
   7  *    Copyright (C) 1995  Linus Torvalds
   8  */
   9
  10 #include <linux/signal.h>
  11 #include <linux/sched.h>
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/string.h>
  15 #include <linux/types.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/mman.h>
  18 #include <linux/mm.h>
  19 #include <linux/swap.h>
  20 #include <linux/smp.h>
  21 #include <linux/init.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/memory.h>
  25 #include <linux/pfn.h>
  26 #include <linux/poison.h>
  27 #include <linux/initrd.h>
  28 #include <linux/export.h>
  29 #include <linux/gfp.h>
  30 #include <linux/memblock.h>
  31 #include <asm/processor.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/pgalloc.h>
  35 #include <asm/dma.h>
  36 #include <asm/lowcore.h>
  37 #include <asm/tlb.h>
  38 #include <asm/tlbflush.h>
  39 #include <asm/sections.h>
  40 #include <asm/ctl_reg.h>
  41 #include <asm/sclp.h>
  42
  43 pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
  44
  45 unsigned long empty_zero_page, zero_page_mask;
  46 EXPORT_SYMBOL(empty_zero_page);
  47 EXPORT_SYMBOL(zero_page_mask);
  48
  49 static void __init setup_zero_pages(void)
  50 {
  51         unsigned int order;
  52         struct page *page;
  53         int i;
  54
  55         /* Latest machines require a mapping granularity of 512KB */
  56         order = 7;
  57
  58         /* Limit number of empty zero pages for small memory sizes */
  59         while (order > 2 && (totalram_pages >> 10) < (1UL << order))
  60                 order--;
  61
  62         empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
  63         if (!empty_zero_page)
  64                 panic("Out of memory in setup_zero_pages");
  65
  66         page = virt_to_page((void *) empty_zero_page);
  67         split_page(page, order);
  68         for (i = 1 << order; i > 0; i--) {
  69                 mark_page_reserved(page);
  70                 page++;
  71         }
  72
  73         zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
  74 }
  75
  76 /*
  77  * paging_init() sets up the page tables
  78  */
  79 void __init paging_init(void)
  80 {
  81         unsigned long max_zone_pfns[MAX_NR_ZONES];
  82         unsigned long pgd_type, asce_bits;
  83
  84         init_mm.pgd = swapper_pg_dir;
  85         if (VMALLOC_END > (1UL << 42)) {
  86                 asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
  87                 pgd_type = _REGION2_ENTRY_EMPTY;
  88         } else {
  89                 asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
  90                 pgd_type = _REGION3_ENTRY_EMPTY;
  91         }
  92         init_mm.context.asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
  93         S390_lowcore.kernel_asce = init_mm.context.asce;
  94         clear_table((unsigned long *) init_mm.pgd, pgd_type,
  95                     sizeof(unsigned long)*2048);
  96         vmem_map_init();
  97
  98         /* enable virtual mapping in kernel mode */
  99         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
 100         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 101         __ctl_load(S390_lowcore.kernel_asce, 13, 13);
 102         __arch_local_irq_stosm(0x04);
 103
 104         sparse_memory_present_with_active_regions(MAX_NUMNODES);
 105         sparse_init();
 106         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 107         max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
 108         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 109         free_area_init_nodes(max_zone_pfns);
 110 }
 111
 112 void mark_rodata_ro(void)
 113 {
 114         /* Text and rodata are already protected. Nothing to do here. */
 115         pr_info("Write protecting the kernel read-only data: %luk\n",
 116                 ((unsigned long)&_eshared - (unsigned long)&_stext) >> 10);
 117 }
 118
 119 void __init mem_init(void)
 120 {
 121         if (MACHINE_HAS_TLB_LC)
 122                 cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
 123         cpumask_set_cpu(0, mm_cpumask(&init_mm));
 124         atomic_set(&init_mm.context.attach_count, 1);
 125
 126         set_max_mapnr(max_low_pfn);
 127         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 128
 129         /* Setup guest page hinting */
 130         cmma_init();
 131
 132         /* this will put all low memory onto the freelists */
 133         free_all_bootmem();
 134         setup_zero_pages();     /* Setup zeroed pages. */
 135
 136         mem_init_print_info(NULL);
 137 }
 138
 139 void free_initmem(void)
 140 {
 141         free_initmem_default(POISON_FREE_INITMEM);
 142 }
 143
 144 #ifdef CONFIG_BLK_DEV_INITRD
 145 void __init free_initrd_mem(unsigned long start, unsigned long end)
 146 {
 147         free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 148                            "initrd");
 149 }
 150 #endif
 151
 152 #ifdef CONFIG_MEMORY_HOTPLUG
 153 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 154 {
 155         unsigned long normal_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
 156         unsigned long dma_end_pfn = PFN_DOWN(MAX_DMA_ADDRESS);
 157         unsigned long start_pfn = PFN_DOWN(start);
 158         unsigned long size_pages = PFN_DOWN(size);
 159         unsigned long nr_pages;
 160         int rc, zone_enum;
 161
 162         rc = vmem_add_mapping(start, size);
 163         if (rc)
 164                 return rc;
 165
 166         while (size_pages > 0) {
 167                 if (start_pfn < dma_end_pfn) {
 168                         nr_pages = (start_pfn + size_pages > dma_end_pfn) ?
 169                                    dma_end_pfn - start_pfn : size_pages;
 170                         zone_enum = ZONE_DMA;
 171                 } else if (start_pfn < normal_end_pfn) {
 172                         nr_pages = (start_pfn + size_pages > normal_end_pfn) ?
 173                                    normal_end_pfn - start_pfn : size_pages;
 174                         zone_enum = ZONE_NORMAL;
 175                 } else {
 176                         nr_pages = size_pages;
 177                         zone_enum = ZONE_MOVABLE;
 178                 }
 179                 rc = __add_pages(nid, NODE_DATA(nid)->node_zones + zone_enum,
 180                                  start_pfn, size_pages);
 181                 if (rc)
 182                         break;
 183                 start_pfn += nr_pages;
 184                 size_pages -= nr_pages;
 185         }
 186         if (rc)
 187                 vmem_remove_mapping(start, size);
 188         return rc;
 189 }
 190
 191 unsigned long memory_block_size_bytes(void)
 192 {
 193         /*
 194          * Make sure the memory block size is always greater
 195          * or equal than the memory increment size.
 196          */
 197         return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
 198 }
 199
 200 #ifdef CONFIG_MEMORY_HOTREMOVE
 201 int arch_remove_memory(u64 start, u64 size)
 202 {
 203         /*
 204          * There is no hardware or firmware interface which could trigger a
 205          * hot memory remove on s390. So there is nothing that needs to be
 206          * implemented.
 207          */
 208         return -EBUSY;
 209 }
 210 #endif
 211 #endif /* CONFIG_MEMORY_HOTPLUG */