text: /*
   * Suspend support specific for s390.
   *
   * Copyright IBM Corp. 2009
   *
   * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
   */
  
  #include <linux/pfn.h>
  #include <linux/suspend.h>
  #include <linux/mm.h>
  #include <asm/ctl_reg.h>
  #include <asm/ipl.h>
  #include <asm/cio.h>
  #include <asm/pci.h>
  #include "entry.h"
  
  /*
   * References to section boundaries
   */
  extern const void __nosave_begin, __nosave_end;
  
  /*
   * The restore of the saved pages in an hibernation image will set
   * the change and referenced bits in the storage key for each page.
   * Overindication of the referenced bits after an hibernation cycle
   * does not cause any harm but the overindication of the change bits
   * would cause trouble.
   * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
   * page to the most significant byte of the associated page frame
   * number in the hibernation image.
   */
  
  /*
   * Key storage is allocated as a linked list of pages.
   * The size of the keys array is (PAGE_SIZE - sizeof(long))
   */
  struct page_key_data {
  	struct page_key_data *next;
  	unsigned char data[];
  };
  
  #define PAGE_KEY_DATA_SIZE	(PAGE_SIZE - sizeof(struct page_key_data *))
  
  static struct page_key_data *page_key_data;
  static struct page_key_data *page_key_rp, *page_key_wp;
  static unsigned long page_key_rx, page_key_wx;
  unsigned long suspend_zero_pages;
  
  /*
   * For each page in the hibernation image one additional byte is
   * stored in the most significant byte of the page frame number.
   * On suspend no additional memory is required but on resume the
   * keys need to be memorized until the page data has been restored.
   * Only then can the storage keys be set to their old state.
   */
  unsigned long page_key_additional_pages(unsigned long pages)
  {
  	return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  }
  
  /*
   * Free page_key_data list of arrays.
   */
  void page_key_free(void)
  {
  	struct page_key_data *pkd;
  
  	while (page_key_data) {
  		pkd = page_key_data;
  		page_key_data = pkd->next;
  		free_page((unsigned long) pkd);
  	}
  }
  
  /*
   * Allocate page_key_data list of arrays with enough room to store
   * one byte for each page in the hibernation image.
   */
  int page_key_alloc(unsigned long pages)
  {
  	struct page_key_data *pk;
  	unsigned long size;
  
  	size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  	while (size--) {
  		pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
  		if (!pk) {
  			page_key_free();
  			return -ENOMEM;
  		}
  		pk->next = page_key_data;
  		page_key_data = pk;
  	}
  	page_key_rp = page_key_wp = page_key_data;
  	page_key_rx = page_key_wx = 0;
  	return 0;
  }
  
  /*
   * Save the storage key into the upper 8 bits of the page frame number.
   */
  void page_key_read(unsigned long *pfn)
  {
  	unsigned long addr;
  
  	addr = (unsigned long) page_address(pfn_to_page(*pfn));
  	*(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
  }
  
  /*
   * Extract the storage key from the upper 8 bits of the page frame number
   * and store it in the page_key_data list of arrays.
   */
  void page_key_memorize(unsigned long *pfn)
  {
  	page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
  	*(unsigned char *) pfn = 0;
  	if (++page_key_wx < PAGE_KEY_DATA_SIZE)
  		return;
  	page_key_wp = page_key_wp->next;
  	page_key_wx = 0;
  }
  
  /*
   * Get the next key from the page_key_data list of arrays and set the
   * storage key of the page referred by @address. If @address refers to
   * a "safe" page the swsusp_arch_resume code will transfer the storage
   * key from the buffer page to the original page.
   */
  void page_key_write(void *address)
  {
  	page_set_storage_key((unsigned long) address,
  			     page_key_rp->data[page_key_rx], 0);
  	if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
  		return;
  	page_key_rp = page_key_rp->next;
  	page_key_rx = 0;
  }
  
  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));
  	unsigned long eshared_pfn = PFN_DOWN(__pa(&_eshared)) - 1;
  	unsigned long stext_pfn = PFN_DOWN(__pa(&_stext));
  
  	/* 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 (pfn >= stext_pfn && pfn <= eshared_pfn)
  		return ipl_info.type == IPL_TYPE_NSS ? 1 : 0;
  	if (tprot(PFN_PHYS(pfn)))
  		return 1;
  	return 0;
  }
  
  /*
   * PM notifier callback for suspend
   */
  static int suspend_pm_cb(struct notifier_block *nb, unsigned long action,
  			 void *ptr)
  {
  	switch (action) {
  	case PM_SUSPEND_PREPARE:
  	case PM_HIBERNATION_PREPARE:
  		suspend_zero_pages = __get_free_pages(GFP_KERNEL, LC_ORDER);
  		if (!suspend_zero_pages)
  			return NOTIFY_BAD;
  		break;
  	case PM_POST_SUSPEND:
  	case PM_POST_HIBERNATION:
  		free_pages(suspend_zero_pages, LC_ORDER);
  		break;
  	default:
  		return NOTIFY_DONE;
  	}
  	return NOTIFY_OK;
  }
  
  static int __init suspend_pm_init(void)
  {
  	pm_notifier(suspend_pm_cb, 0);
  	return 0;
  }
  arch_initcall(suspend_pm_init);
  
  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();
  }
  
  /* Called at the end of swsusp_arch_resume */
  void s390_early_resume(void)
  {
  	lgr_info_log();
  	channel_subsystem_reinit();
  	zpci_rescan();
  }
  