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 <asm/system.h>
  11
  12 /*
  13  * References to section boundaries
  14  */
  15 extern const void __nosave_begin, __nosave_end;
  16
  17 int pfn_is_nosave(unsigned long pfn)
  18 {
  19         unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
  20         unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
  21
  22         /* Always save lowcore pages (LC protection might be enabled). */
  23         if (pfn <= LC_PAGES)
  24                 return 0;
  25         if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
  26                 return 1;
  27         /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
  28         if (tprot(PFN_PHYS(pfn)))
  29                 return 1;
  30         return 0;
  31 }
  32
  33 void save_processor_state(void)
  34 {
  35         /* swsusp_arch_suspend() actually saves all cpu register contents.
  36          * Machine checks must be disabled since swsusp_arch_suspend() stores
  37          * register contents to their lowcore save areas. That's the same
  38          * place where register contents on machine checks would be saved.
  39          * To avoid register corruption disable machine checks.
  40          * We must also disable machine checks in the new psw mask for
  41          * program checks, since swsusp_arch_suspend() may generate program
  42          * checks. Disabling machine checks for all other new psw masks is
  43          * just paranoia.
  44          */
  45         local_mcck_disable();
  46         /* Disable lowcore protection */
  47         __ctl_clear_bit(0,28);
  48         S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
  49         S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
  50         S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
  51         S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
  52 }
  53
  54 void restore_processor_state(void)
  55 {
  56         S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
  57         S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
  58         S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
  59         S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
  60         /* Enable lowcore protection */
  61         __ctl_set_bit(0,28);
  62         local_mcck_enable();
  63 }