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 #include "entry.h"
  17
  18 /*
  19  * References to section boundaries
  20  */
  21 extern const void __nosave_begin, __nosave_end;
  22
  23 /*
  24  * The restore of the saved pages in an hibernation image will set
  25  * the change and referenced bits in the storage key for each page.
  26  * Overindication of the referenced bits after an hibernation cycle
  27  * does not cause any harm but the overindication of the change bits
  28  * would cause trouble.
  29  * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
  30  * page to the most significant byte of the associated page frame
  31  * number in the hibernation image.
  32  */
  33
  34 /*
  35  * Key storage is allocated as a linked list of pages.
  36  * The size of the keys array is (PAGE_SIZE - sizeof(long))
  37  */
  38 struct page_key_data {
  39         struct page_key_data *next;
  40         unsigned char data[];
  41 };
  42
  43 #define PAGE_KEY_DATA_SIZE      (PAGE_SIZE - sizeof(struct page_key_data *))
  44
  45 static struct page_key_data *page_key_data;
  46 static struct page_key_data *page_key_rp, *page_key_wp;
  47 static unsigned long page_key_rx, page_key_wx;
  48 unsigned long suspend_zero_pages;
  49
  50 /*
  51  * For each page in the hibernation image one additional byte is
  52  * stored in the most significant byte of the page frame number.
  53  * On suspend no additional memory is required but on resume the
  54  * keys need to be memorized until the page data has been restored.
  55  * Only then can the storage keys be set to their old state.
  56  */
  57 unsigned long page_key_additional_pages(unsigned long pages)
  58 {
  59         return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  60 }
  61
  62 /*
  63  * Free page_key_data list of arrays.
  64  */
  65 void page_key_free(void)
  66 {
  67         struct page_key_data *pkd;
  68
  69         while (page_key_data) {
  70                 pkd = page_key_data;
  71                 page_key_data = pkd->next;
  72                 free_page((unsigned long) pkd);
  73         }
  74 }
  75
  76 /*
  77  * Allocate page_key_data list of arrays with enough room to store
  78  * one byte for each page in the hibernation image.
  79  */
  80 int page_key_alloc(unsigned long pages)
  81 {
  82         struct page_key_data *pk;
  83         unsigned long size;
  84
  85         size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  86         while (size--) {
  87                 pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
  88                 if (!pk) {
  89                         page_key_free();
  90                         return -ENOMEM;
  91                 }
  92                 pk->next = page_key_data;
  93                 page_key_data = pk;
  94         }
  95         page_key_rp = page_key_wp = page_key_data;
  96         page_key_rx = page_key_wx = 0;
  97         return 0;
  98 }
  99
 100 /*
 101  * Save the storage key into the upper 8 bits of the page frame number.
 102  */
 103 void page_key_read(unsigned long *pfn)
 104 {
 105         unsigned long addr;
 106
 107         addr = (unsigned long) page_address(pfn_to_page(*pfn));
 108         *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
 109 }
 110
 111 /*
 112  * Extract the storage key from the upper 8 bits of the page frame number
 113  * and store it in the page_key_data list of arrays.
 114  */
 115 void page_key_memorize(unsigned long *pfn)
 116 {
 117         page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
 118         *(unsigned char *) pfn = 0;
 119         if (++page_key_wx < PAGE_KEY_DATA_SIZE)
 120                 return;
 121         page_key_wp = page_key_wp->next;
 122         page_key_wx = 0;
 123 }
 124
 125 /*
 126  * Get the next key from the page_key_data list of arrays and set the
 127  * storage key of the page referred by @address. If @address refers to
 128  * a "safe" page the swsusp_arch_resume code will transfer the storage
 129  * key from the buffer page to the original page.
 130  */
 131 void page_key_write(void *address)
 132 {
 133         page_set_storage_key((unsigned long) address,
 134                              page_key_rp->data[page_key_rx], 0);
 135         if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
 136                 return;
 137         page_key_rp = page_key_rp->next;
 138         page_key_rx = 0;
 139 }
 140
 141 int pfn_is_nosave(unsigned long pfn)
 142 {
 143         unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
 144         unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
 145
 146         /* Always save lowcore pages (LC protection might be enabled). */
 147         if (pfn <= LC_PAGES)
 148                 return 0;
 149         if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
 150                 return 1;
 151         /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
 152         if (tprot(PFN_PHYS(pfn)))
 153                 return 1;
 154         return 0;
 155 }
 156
 157 /*
 158  * PM notifier callback for suspend
 159  */
 160 static int suspend_pm_cb(struct notifier_block *nb, unsigned long action,
 161                          void *ptr)
 162 {
 163         switch (action) {
 164         case PM_SUSPEND_PREPARE:
 165         case PM_HIBERNATION_PREPARE:
 166                 suspend_zero_pages = __get_free_pages(GFP_KERNEL, LC_ORDER);
 167                 if (!suspend_zero_pages)
 168                         return NOTIFY_BAD;
 169                 break;
 170         case PM_POST_SUSPEND:
 171         case PM_POST_HIBERNATION:
 172                 free_pages(suspend_zero_pages, LC_ORDER);
 173                 break;
 174         default:
 175                 return NOTIFY_DONE;
 176         }
 177         return NOTIFY_OK;
 178 }
 179
 180 static int __init suspend_pm_init(void)
 181 {
 182         pm_notifier(suspend_pm_cb, 0);
 183         return 0;
 184 }
 185 arch_initcall(suspend_pm_init);
 186
 187 void save_processor_state(void)
 188 {
 189         /* swsusp_arch_suspend() actually saves all cpu register contents.
 190          * Machine checks must be disabled since swsusp_arch_suspend() stores
 191          * register contents to their lowcore save areas. That's the same
 192          * place where register contents on machine checks would be saved.
 193          * To avoid register corruption disable machine checks.
 194          * We must also disable machine checks in the new psw mask for
 195          * program checks, since swsusp_arch_suspend() may generate program
 196          * checks. Disabling machine checks for all other new psw masks is
 197          * just paranoia.
 198          */
 199         local_mcck_disable();
 200         /* Disable lowcore protection */
 201         __ctl_clear_bit(0,28);
 202         S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
 203         S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
 204         S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
 205         S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
 206 }
 207
 208 void restore_processor_state(void)
 209 {
 210         S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
 211         S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
 212         S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
 213         S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
 214         /* Enable lowcore protection */
 215         __ctl_set_bit(0,28);
 216         local_mcck_enable();
 217 }
 218
 219 /* Called at the end of swsusp_arch_resume */
 220 void s390_early_resume(void)
 221 {
 222         lgr_info_log();
 223         channel_subsystem_reinit();
 224         zpci_rescan();
 225 }