LXR linux/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 <linux/suspend.h>
  11#include <linux/mm.h>
  12#include <asm/ctl_reg.h>
  13#include <asm/ipl.h>
  14#include <asm/cio.h>
  15#include <asm/pci.h>
  16#include "entry.h"
  17
  18/*
  19 * References to section boundaries
  20 */
  21extern const void __nosave_begin, __nosave_end;
  22
  23/*
  24 * The restore of the saved pages in an hibernation image will set
  25 * the change and referenced bits in the storage key for each page.
  26 * Overindication of the referenced bits after an hibernation cycle
  27 * does not cause any harm but the overindication of the change bits
  28 * would cause trouble.
  29 * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
  30 * page to the most significant byte of the associated page frame
  31 * number in the hibernation image.
  32 */
  33
  34/*
  35 * Key storage is allocated as a linked list of pages.
  36 * The size of the keys array is (PAGE_SIZE - sizeof(long))
  37 */
  38struct page_key_data {
  39        struct page_key_data *next;
  40        unsigned char data[];
  41};
  42
  43#define PAGE_KEY_DATA_SIZE      (PAGE_SIZE - sizeof(struct page_key_data *))
  44
  45static struct page_key_data *page_key_data;
  46static struct page_key_data *page_key_rp, *page_key_wp;
  47static unsigned long page_key_rx, page_key_wx;
  48unsigned long suspend_zero_pages;
  49
  50/*
  51 * For each page in the hibernation image one additional byte is
  52 * stored in the most significant byte of the page frame number.
  53 * On suspend no additional memory is required but on resume the
  54 * keys need to be memorized until the page data has been restored.
  55 * Only then can the storage keys be set to their old state.
  56 */
  57unsigned long page_key_additional_pages(unsigned long pages)
  58{
  59        return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  60}
  61
  62/*
  63 * Free page_key_data list of arrays.
  64 */
  65void page_key_free(void)
  66{
  67        struct page_key_data *pkd;
  68
  69        while (page_key_data) {
  70                pkd = page_key_data;
  71                page_key_data = pkd->next;
  72                free_page((unsigned long) pkd);
  73        }
  74}
  75
  76/*
  77 * Allocate page_key_data list of arrays with enough room to store
  78 * one byte for each page in the hibernation image.
  79 */
  80int page_key_alloc(unsigned long pages)
  81{
  82        struct page_key_data *pk;
  83        unsigned long size;
  84
  85        size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  86        while (size--) {
  87                pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
  88                if (!pk) {
  89                        page_key_free();
  90                        return -ENOMEM;
  91                }
  92                pk->next = page_key_data;
  93                page_key_data = pk;
  94        }
  95        page_key_rp = page_key_wp = page_key_data;
  96        page_key_rx = page_key_wx = 0;
  97        return 0;
  98}
  99
 100/*
 101 * Save the storage key into the upper 8 bits of the page frame number.
 102 */
 103void page_key_read(unsigned long *pfn)
 104{
 105        unsigned long addr;
 106
 107        addr = (unsigned long) page_address(pfn_to_page(*pfn));
 108        *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
 109}
 110
 111/*
 112 * Extract the storage key from the upper 8 bits of the page frame number
 113 * and store it in the page_key_data list of arrays.
 114 */
 115void page_key_memorize(unsigned long *pfn)
 116{
 117        page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
 118        *(unsigned char *) pfn = 0;
 119        if (++page_key_wx < PAGE_KEY_DATA_SIZE)
 120                return;
 121        page_key_wp = page_key_wp->next;
 122        page_key_wx = 0;
 123}
 124
 125/*
 126 * Get the next key from the page_key_data list of arrays and set the
 127 * storage key of the page referred by @address. If @address refers to
 128 * a "safe" page the swsusp_arch_resume code will transfer the storage
 129 * key from the buffer page to the original page.
 130 */
 131void page_key_write(void *address)
 132{
 133        page_set_storage_key((unsigned long) address,
 134                             page_key_rp->data[page_key_rx], 0);
 135        if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
 136                return;
 137        page_key_rp = page_key_rp->next;
 138        page_key_rx = 0;
 139}
 140
 141int pfn_is_nosave(unsigned long pfn)
 142{
 143        unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
 144        unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
 145
 146        /* Always save lowcore pages (LC protection might be enabled). */
 147        if (pfn <= LC_PAGES)
 148                return 0;
 149        if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
 150                return 1;
 151        /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
 152        if (tprot(PFN_PHYS(pfn)))
 153                return 1;
 154        return 0;
 155}
 156
 157/*
 158 * PM notifier callback for suspend
 159 */
 160static int suspend_pm_cb(struct notifier_block *nb, unsigned long action,
 161                         void *ptr)
 162{
 163        switch (action) {
 164        case PM_SUSPEND_PREPARE:
 165        case PM_HIBERNATION_PREPARE:
 166                suspend_zero_pages = __get_free_pages(GFP_KERNEL, LC_ORDER);
 167                if (!suspend_zero_pages)
 168                        return NOTIFY_BAD;
 169                break;
 170        case PM_POST_SUSPEND:
 171        case PM_POST_HIBERNATION:
 172                free_pages(suspend_zero_pages, LC_ORDER);
 173                break;
 174        default:
 175                return NOTIFY_DONE;
 176        }
 177        return NOTIFY_OK;
 178}
 179
 180static int __init suspend_pm_init(void)
 181{
 182        pm_notifier(suspend_pm_cb, 0);
 183        return 0;
 184}
 185arch_initcall(suspend_pm_init);
 186
 187void save_processor_state(void)
 188{
 189        /* swsusp_arch_suspend() actually saves all cpu register contents.
 190         * Machine checks must be disabled since swsusp_arch_suspend() stores
 191         * register contents to their lowcore save areas. That's the same
 192         * place where register contents on machine checks would be saved.
 193         * To avoid register corruption disable machine checks.
 194         * We must also disable machine checks in the new psw mask for
 195         * program checks, since swsusp_arch_suspend() may generate program
 196         * checks. Disabling machine checks for all other new psw masks is
 197         * just paranoia.
 198         */
 199        local_mcck_disable();
 200        /* Disable lowcore protection */
 201        __ctl_clear_bit(0,28);
 202        S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
 203        S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
 204        S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
 205        S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
 206}
 207
 208void restore_processor_state(void)
 209{
 210        S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
 211        S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
 212        S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
 213        S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
 214        /* Enable lowcore protection */
 215        __ctl_set_bit(0,28);
 216        local_mcck_enable();
 217}
 218
 219/* Called at the end of swsusp_arch_resume */
 220void s390_early_resume(void)
 221{
 222        lgr_info_log();
 223        channel_subsystem_reinit();
 224        zpci_rescan();
 225}
 226