linux/arch/s390/kernel/suspend.c

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/*
* Suspend support specific for s390.
*
* Copyright IBM Corp. 2009
*
* Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
*/
#include <linux/pfn.h>
#include <asm/system.h>
/*
* References to section boundaries
*/
extern const void __nosave_begin, __nosave_end;
int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
/* Always save lowcore pages (LC protection might be enabled). */
if (pfn <= LC_PAGES)
return 0;
if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
return 1;
/* Skip memory holes and read-only pages (NSS, DCSS, ...). */
if (tprot(PFN_PHYS(pfn)))
return 1;
return 0;
}
void save_processor_state(void)
{
/* swsusp_arch_suspend() actually saves all cpu register contents.
* Machine checks must be disabled since swsusp_arch_suspend() stores
* register contents to their lowcore save areas. That's the same
* place where register contents on machine checks would be saved.
* To avoid register corruption disable machine checks.
* We must also disable machine checks in the new psw mask for
* program checks, since swsusp_arch_suspend() may generate program
* checks. Disabling machine checks for all other new psw masks is
* just paranoia.
*/
local_mcck_disable();
/* Disable lowcore protection */
__ctl_clear_bit(0,28);
S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
}
void restore_processor_state(void)
{
S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
/* Enable lowcore protection */
__ctl_set_bit(0,28);
local_mcck_enable();
}