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         S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
  93         clear_table((unsigned long *) init_mm.pgd, pgd_type,
  94                     sizeof(unsigned long)*2048);
  95         vmem_map_init();
  96
  97         /* enable virtual mapping in kernel mode */
  98         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  99         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 100         __ctl_load(S390_lowcore.kernel_asce, 13, 13);
 101         __arch_local_irq_stosm(0x04);
 102
 103         sparse_memory_present_with_active_regions(MAX_NUMNODES);
 104         sparse_init();
 105         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 106         max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
 107         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 108         free_area_init_nodes(max_zone_pfns);
 109 }
 110
 111 void mark_rodata_ro(void)
 112 {
 113         /* Text and rodata are already protected. Nothing to do here. */
 114         pr_info("Write protecting the kernel read-only data: %luk\n",
 115                 ((unsigned long)&_eshared - (unsigned long)&_stext) >> 10);
 116 }
 117
 118 void __init mem_init(void)
 119 {
 120         if (MACHINE_HAS_TLB_LC)
 121                 cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
 122         cpumask_set_cpu(0, mm_cpumask(&init_mm));
 123         atomic_set(&init_mm.context.attach_count, 1);
 124
 125         set_max_mapnr(max_low_pfn);
 126         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 127
 128         /* Setup guest page hinting */
 129         cmma_init();
 130
 131         /* this will put all low memory onto the freelists */
 132         free_all_bootmem();
 133         setup_zero_pages();     /* Setup zeroed pages. */
 134
 135         mem_init_print_info(NULL);
 136 }
 137
 138 void free_initmem(void)
 139 {
 140         free_initmem_default(POISON_FREE_INITMEM);
 141 }
 142
 143 #ifdef CONFIG_BLK_DEV_INITRD
 144 void __init free_initrd_mem(unsigned long start, unsigned long end)
 145 {
 146         free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 147                            "initrd");
 148 }
 149 #endif
 150
 151 #ifdef CONFIG_MEMORY_HOTPLUG
 152 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 153 {
 154         unsigned long normal_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
 155         unsigned long dma_end_pfn = PFN_DOWN(MAX_DMA_ADDRESS);
 156         unsigned long start_pfn = PFN_DOWN(start);
 157         unsigned long size_pages = PFN_DOWN(size);
 158         unsigned long nr_pages;
 159         int rc, zone_enum;
 160
 161         rc = vmem_add_mapping(start, size);
 162         if (rc)
 163                 return rc;
 164
 165         while (size_pages > 0) {
 166                 if (start_pfn < dma_end_pfn) {
 167                         nr_pages = (start_pfn + size_pages > dma_end_pfn) ?
 168                                    dma_end_pfn - start_pfn : size_pages;
 169                         zone_enum = ZONE_DMA;
 170                 } else if (start_pfn < normal_end_pfn) {
 171                         nr_pages = (start_pfn + size_pages > normal_end_pfn) ?
 172                                    normal_end_pfn - start_pfn : size_pages;
 173                         zone_enum = ZONE_NORMAL;
 174                 } else {
 175                         nr_pages = size_pages;
 176                         zone_enum = ZONE_MOVABLE;
 177                 }
 178                 rc = __add_pages(nid, NODE_DATA(nid)->node_zones + zone_enum,
 179                                  start_pfn, size_pages);
 180                 if (rc)
 181                         break;
 182                 start_pfn += nr_pages;
 183                 size_pages -= nr_pages;
 184         }
 185         if (rc)
 186                 vmem_remove_mapping(start, size);
 187         return rc;
 188 }
 189
 190 unsigned long memory_block_size_bytes(void)
 191 {
 192         /*
 193          * Make sure the memory block size is always greater
 194          * or equal than the memory increment size.
 195          */
 196         return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
 197 }
 198
 199 #ifdef CONFIG_MEMORY_HOTREMOVE
 200 int arch_remove_memory(u64 start, u64 size)
 201 {
 202         /*
 203          * There is no hardware or firmware interface which could trigger a
 204          * hot memory remove on s390. So there is nothing that needs to be
 205          * implemented.
 206          */
 207         return -EBUSY;
 208 }
 209 #endif
 210 #endif /* CONFIG_MEMORY_HOTPLUG */