183 lines
5.1 KiB
C
183 lines
5.1 KiB
C
/*
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* Suspend support specific for s390.
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*
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* Copyright IBM Corp. 2009
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*
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* Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
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*/
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#include <linux/pfn.h>
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#include <linux/suspend.h>
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#include <linux/mm.h>
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#include <asm/ctl_reg.h>
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/*
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* References to section boundaries
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*/
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extern const void __nosave_begin, __nosave_end;
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/*
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* The restore of the saved pages in an hibernation image will set
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* the change and referenced bits in the storage key for each page.
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* Overindication of the referenced bits after an hibernation cycle
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* does not cause any harm but the overindication of the change bits
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* would cause trouble.
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* Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
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* page to the most significant byte of the associated page frame
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* number in the hibernation image.
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*/
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/*
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* Key storage is allocated as a linked list of pages.
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* The size of the keys array is (PAGE_SIZE - sizeof(long))
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*/
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struct page_key_data {
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struct page_key_data *next;
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unsigned char data[];
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};
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#define PAGE_KEY_DATA_SIZE (PAGE_SIZE - sizeof(struct page_key_data *))
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static struct page_key_data *page_key_data;
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static struct page_key_data *page_key_rp, *page_key_wp;
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static unsigned long page_key_rx, page_key_wx;
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/*
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* For each page in the hibernation image one additional byte is
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* stored in the most significant byte of the page frame number.
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* On suspend no additional memory is required but on resume the
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* keys need to be memorized until the page data has been restored.
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* Only then can the storage keys be set to their old state.
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*/
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unsigned long page_key_additional_pages(unsigned long pages)
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{
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return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
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}
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/*
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* Free page_key_data list of arrays.
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*/
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void page_key_free(void)
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{
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struct page_key_data *pkd;
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while (page_key_data) {
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pkd = page_key_data;
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page_key_data = pkd->next;
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free_page((unsigned long) pkd);
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}
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}
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/*
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* Allocate page_key_data list of arrays with enough room to store
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* one byte for each page in the hibernation image.
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*/
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int page_key_alloc(unsigned long pages)
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{
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struct page_key_data *pk;
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unsigned long size;
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size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
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while (size--) {
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pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
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if (!pk) {
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page_key_free();
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return -ENOMEM;
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}
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pk->next = page_key_data;
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page_key_data = pk;
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}
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page_key_rp = page_key_wp = page_key_data;
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page_key_rx = page_key_wx = 0;
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return 0;
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}
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/*
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* Save the storage key into the upper 8 bits of the page frame number.
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*/
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void page_key_read(unsigned long *pfn)
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{
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unsigned long addr;
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addr = (unsigned long) page_address(pfn_to_page(*pfn));
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*(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
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}
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/*
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* Extract the storage key from the upper 8 bits of the page frame number
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* and store it in the page_key_data list of arrays.
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*/
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void page_key_memorize(unsigned long *pfn)
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{
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page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
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*(unsigned char *) pfn = 0;
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if (++page_key_wx < PAGE_KEY_DATA_SIZE)
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return;
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page_key_wp = page_key_wp->next;
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page_key_wx = 0;
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}
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/*
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* Get the next key from the page_key_data list of arrays and set the
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* storage key of the page referred by @address. If @address refers to
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* a "safe" page the swsusp_arch_resume code will transfer the storage
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* key from the buffer page to the original page.
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*/
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void page_key_write(void *address)
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{
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page_set_storage_key((unsigned long) address,
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page_key_rp->data[page_key_rx], 0);
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if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
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return;
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page_key_rp = page_key_rp->next;
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page_key_rx = 0;
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}
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int pfn_is_nosave(unsigned long pfn)
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{
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unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
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unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
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/* Always save lowcore pages (LC protection might be enabled). */
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if (pfn <= LC_PAGES)
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return 0;
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if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
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return 1;
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/* Skip memory holes and read-only pages (NSS, DCSS, ...). */
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if (tprot(PFN_PHYS(pfn)))
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return 1;
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return 0;
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}
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void save_processor_state(void)
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{
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/* swsusp_arch_suspend() actually saves all cpu register contents.
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* Machine checks must be disabled since swsusp_arch_suspend() stores
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* register contents to their lowcore save areas. That's the same
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* place where register contents on machine checks would be saved.
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* To avoid register corruption disable machine checks.
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* We must also disable machine checks in the new psw mask for
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* program checks, since swsusp_arch_suspend() may generate program
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* checks. Disabling machine checks for all other new psw masks is
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* just paranoia.
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*/
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local_mcck_disable();
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/* Disable lowcore protection */
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__ctl_clear_bit(0,28);
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S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
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S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
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S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
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S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
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}
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void restore_processor_state(void)
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{
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S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
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S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
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S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
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S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
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/* Enable lowcore protection */
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__ctl_set_bit(0,28);
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local_mcck_enable();
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}
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