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/suspend.h>
  10 #include <linux/reboot.h>
  11 #include <linux/pfn.h>
  12 #include <linux/mm.h>
  13 #include <asm/sections.h>
  14 #include <asm/system.h>
  15 #include <asm/ipl.h>
  16
  17 /*
  18  * References to section boundaries
  19  */
  20 extern const void __nosave_begin, __nosave_end;
  21
  22 /*
  23  *  check if given pfn is in the 'nosave' or in the read only NSS section
  24  */
  25 int pfn_is_nosave(unsigned long pfn)
  26 {
  27         unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
  28         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end))
  29                                         >> PAGE_SHIFT;
  30         unsigned long eshared_pfn = PFN_DOWN(__pa(&_eshared)) - 1;
  31         unsigned long stext_pfn = PFN_DOWN(__pa(&_stext));
  32
  33         if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
  34                 return 1;
  35         if (pfn >= stext_pfn && pfn <= eshared_pfn) {
  36                 if (ipl_info.type == IPL_TYPE_NSS)
  37                         return 1;
  38         } else if ((tprot(pfn * PAGE_SIZE) && pfn > 0))
  39                 return 1;
  40         return 0;
  41 }
  42
  43 void save_processor_state(void)
  44 {
  45         /* swsusp_arch_suspend() actually saves all cpu register contents.
  46          * Machine checks must be disabled since swsusp_arch_suspend() stores
  47          * register contents to their lowcore save areas. That's the same
  48          * place where register contents on machine checks would be saved.
  49          * To avoid register corruption disable machine checks.
  50          * We must also disable machine checks in the new psw mask for
  51          * program checks, since swsusp_arch_suspend() may generate program
  52          * checks. Disabling machine checks for all other new psw masks is
  53          * just paranoia.
  54          */
  55         local_mcck_disable();
  56         /* Disable lowcore protection */
  57         __ctl_clear_bit(0,28);
  58         S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
  59         S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
  60         S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
  61         S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
  62 }
  63
  64 void restore_processor_state(void)
  65 {
  66         S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
  67         S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
  68         S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
  69         S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
  70         /* Enable lowcore protection */
  71         __ctl_set_bit(0,28);
  72         local_mcck_enable();
  73 }