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