arch/s390/kernel/suspend.c

   1 /*
   2  * Suspend support specific for s390.
   3  *
   4  * Copyright IBM Corp. 2009
   5  *
   6  * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
   7  */
   8
   9 #include <linux/pfn.h>
  10 #include <linux/suspend.h>
  11 #include <linux/mm.h>
  12 #include <asm/ctl_reg.h>
  13 #include <asm/ipl.h>
  14 #include <asm/cio.h>
  15 #include <asm/pci.h>
  16
  17 /*
  18  * References to section boundaries
  19  */
  20 extern const void __nosave_begin, __nosave_end;
  21
  22 /*
  23  * The restore of the saved pages in an hibernation image will set
  24  * the change and referenced bits in the storage key for each page.
  25  * Overindication of the referenced bits after an hibernation cycle
  26  * does not cause any harm but the overindication of the change bits
  27  * would cause trouble.
  28  * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
  29  * page to the most significant byte of the associated page frame
  30  * number in the hibernation image.
  31  */
  32
  33 /*
  34  * Key storage is allocated as a linked list of pages.
  35  * The size of the keys array is (PAGE_SIZE - sizeof(long))
  36  */
  37 struct page_key_data {
  38         struct page_key_data *next;
  39         unsigned char data[];
  40 };
  41
  42 #define PAGE_KEY_DATA_SIZE      (PAGE_SIZE - sizeof(struct page_key_data *))
  43
  44 static struct page_key_data *page_key_data;
  45 static struct page_key_data *page_key_rp, *page_key_wp;
  46 static unsigned long page_key_rx, page_key_wx;
  47 unsigned long suspend_zero_pages;
  48
  49 /*
  50  * For each page in the hibernation image one additional byte is
  51  * stored in the most significant byte of the page frame number.
  52  * On suspend no additional memory is required but on resume the
  53  * keys need to be memorized until the page data has been restored.
  54  * Only then can the storage keys be set to their old state.
  55  */
  56 unsigned long page_key_additional_pages(unsigned long pages)
  57 {
  58         return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  59 }
  60
  61 /*
  62  * Free page_key_data list of arrays.
  63  */
  64 void page_key_free(void)
  65 {
  66         struct page_key_data *pkd;
  67
  68         while (page_key_data) {
  69                 pkd = page_key_data;
  70                 page_key_data = pkd->next;
  71                 free_page((unsigned long) pkd);
  72         }
  73 }
  74
  75 /*
  76  * Allocate page_key_data list of arrays with enough room to store
  77  * one byte for each page in the hibernation image.
  78  */
  79 int page_key_alloc(unsigned long pages)
  80 {
  81         struct page_key_data *pk;
  82         unsigned long size;
  83
  84         size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  85         while (size--) {
  86                 pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
  87                 if (!pk) {
  88                         page_key_free();
  89                         return -ENOMEM;
  90                 }
  91                 pk->next = page_key_data;
  92                 page_key_data = pk;
  93         }
  94         page_key_rp = page_key_wp = page_key_data;
  95         page_key_rx = page_key_wx = 0;
  96         return 0;
  97 }
  98
  99 /*
 100  * Save the storage key into the upper 8 bits of the page frame number.
 101  */
 102 void page_key_read(unsigned long *pfn)
 103 {
 104         unsigned long addr;
 105
 106         addr = (unsigned long) page_address(pfn_to_page(*pfn));
 107         *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
 108 }
 109
 110 /*
 111  * Extract the storage key from the upper 8 bits of the page frame number
 112  * and store it in the page_key_data list of arrays.
 113  */
 114 void page_key_memorize(unsigned long *pfn)
 115 {
 116         page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
 117         *(unsigned char *) pfn = 0;
 118         if (++page_key_wx < PAGE_KEY_DATA_SIZE)
 119                 return;
 120         page_key_wp = page_key_wp->next;
 121         page_key_wx = 0;
 122 }
 123
 124 /*
 125  * Get the next key from the page_key_data list of arrays and set the
 126  * storage key of the page referred by @address. If @address refers to
 127  * a "safe" page the swsusp_arch_resume code will transfer the storage
 128  * key from the buffer page to the original page.
 129  */
 130 void page_key_write(void *address)
 131 {
 132         page_set_storage_key((unsigned long) address,
 133                              page_key_rp->data[page_key_rx], 0);
 134         if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
 135                 return;
 136         page_key_rp = page_key_rp->next;
 137         page_key_rx = 0;
 138 }
 139
 140 int pfn_is_nosave(unsigned long pfn)
 141 {
 142         unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
 143         unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
 144
 145         /* Always save lowcore pages (LC protection might be enabled). */
 146         if (pfn <= LC_PAGES)
 147                 return 0;
 148         if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
 149                 return 1;
 150         /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
 151         if (tprot(PFN_PHYS(pfn)))
 152                 return 1;
 153         return 0;
 154 }
 155
 156 /*
 157  * PM notifier callback for suspend
 158  */
 159 static int suspend_pm_cb(struct notifier_block *nb, unsigned long action,
 160                          void *ptr)
 161 {
 162         switch (action) {
 163         case PM_SUSPEND_PREPARE:
 164         case PM_HIBERNATION_PREPARE:
 165                 suspend_zero_pages = __get_free_pages(GFP_KERNEL, LC_ORDER);
 166                 if (!suspend_zero_pages)
 167                         return NOTIFY_BAD;
 168                 break;
 169         case PM_POST_SUSPEND:
 170         case PM_POST_HIBERNATION:
 171                 free_pages(suspend_zero_pages, LC_ORDER);
 172                 break;
 173         default:
 174                 return NOTIFY_DONE;
 175         }
 176         return NOTIFY_OK;
 177 }
 178
 179 static int __init suspend_pm_init(void)
 180 {
 181         pm_notifier(suspend_pm_cb, 0);
 182         return 0;
 183 }
 184 arch_initcall(suspend_pm_init);
 185
 186 void save_processor_state(void)
 187 {
 188         /* swsusp_arch_suspend() actually saves all cpu register contents.
 189          * Machine checks must be disabled since swsusp_arch_suspend() stores
 190          * register contents to their lowcore save areas. That's the same
 191          * place where register contents on machine checks would be saved.
 192          * To avoid register corruption disable machine checks.
 193          * We must also disable machine checks in the new psw mask for
 194          * program checks, since swsusp_arch_suspend() may generate program
 195          * checks. Disabling machine checks for all other new psw masks is
 196          * just paranoia.
 197          */
 198         local_mcck_disable();
 199         /* Disable lowcore protection */
 200         __ctl_clear_bit(0,28);
 201         S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
 202         S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
 203         S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
 204         S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
 205 }
 206
 207 void restore_processor_state(void)
 208 {
 209         S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
 210         S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
 211         S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
 212         S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
 213         /* Enable lowcore protection */
 214         __ctl_set_bit(0,28);
 215         local_mcck_enable();
 216 }
 217
 218 /* Called at the end of swsusp_arch_resume */
 219 void s390_early_resume(void)
 220 {
 221         lgr_info_log();
 222         channel_subsystem_reinit();
 223         zpci_rescan();
 224 }