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 <linux/pci.h>
  13#include <asm/ctl_reg.h>
  14#include <asm/ipl.h>
  15#include <asm/cio.h>
  16#include <asm/sections.h>
  17#include "entry.h"
  18
  19/*
  20 * The restore of the saved pages in an hibernation image will set
  21 * the change and referenced bits in the storage key for each page.
  22 * Overindication of the referenced bits after an hibernation cycle
  23 * does not cause any harm but the overindication of the change bits
  24 * would cause trouble.
  25 * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
  26 * page to the most significant byte of the associated page frame
  27 * number in the hibernation image.
  28 */
  29
  30/*
  31 * Key storage is allocated as a linked list of pages.
  32 * The size of the keys array is (PAGE_SIZE - sizeof(long))
  33 */
  34struct page_key_data {
  35        struct page_key_data *next;
  36        unsigned char data[];
  37};
  38
  39#define PAGE_KEY_DATA_SIZE      (PAGE_SIZE - sizeof(struct page_key_data *))
  40
  41static struct page_key_data *page_key_data;
  42static struct page_key_data *page_key_rp, *page_key_wp;
  43static unsigned long page_key_rx, page_key_wx;
  44unsigned long suspend_zero_pages;
  45
  46/*
  47 * For each page in the hibernation image one additional byte is
  48 * stored in the most significant byte of the page frame number.
  49 * On suspend no additional memory is required but on resume the
  50 * keys need to be memorized until the page data has been restored.
  51 * Only then can the storage keys be set to their old state.
  52 */
  53unsigned long page_key_additional_pages(unsigned long pages)
  54{
  55        return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  56}
  57
  58/*
  59 * Free page_key_data list of arrays.
  60 */
  61void page_key_free(void)
  62{
  63        struct page_key_data *pkd;
  64
  65        while (page_key_data) {
  66                pkd = page_key_data;
  67                page_key_data = pkd->next;
  68                free_page((unsigned long) pkd);
  69        }
  70}
  71
  72/*
  73 * Allocate page_key_data list of arrays with enough room to store
  74 * one byte for each page in the hibernation image.
  75 */
  76int page_key_alloc(unsigned long pages)
  77{
  78        struct page_key_data *pk;
  79        unsigned long size;
  80
  81        size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
  82        while (size--) {
  83                pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
  84                if (!pk) {
  85                        page_key_free();
  86                        return -ENOMEM;
  87                }
  88                pk->next = page_key_data;
  89                page_key_data = pk;
  90        }
  91        page_key_rp = page_key_wp = page_key_data;
  92        page_key_rx = page_key_wx = 0;
  93        return 0;
  94}
  95
  96/*
  97 * Save the storage key into the upper 8 bits of the page frame number.
  98 */
  99void page_key_read(unsigned long *pfn)
 100{
 101        unsigned long addr;
 102
 103        addr = (unsigned long) page_address(pfn_to_page(*pfn));
 104        *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
 105}
 106
 107/*
 108 * Extract the storage key from the upper 8 bits of the page frame number
 109 * and store it in the page_key_data list of arrays.
 110 */
 111void page_key_memorize(unsigned long *pfn)
 112{
 113        page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
 114        *(unsigned char *) pfn = 0;
 115        if (++page_key_wx < PAGE_KEY_DATA_SIZE)
 116                return;
 117        page_key_wp = page_key_wp->next;
 118        page_key_wx = 0;
 119}
 120
 121/*
 122 * Get the next key from the page_key_data list of arrays and set the
 123 * storage key of the page referred by @address. If @address refers to
 124 * a "safe" page the swsusp_arch_resume code will transfer the storage
 125 * key from the buffer page to the original page.
 126 */
 127void page_key_write(void *address)
 128{
 129        page_set_storage_key((unsigned long) address,
 130                             page_key_rp->data[page_key_rx], 0);
 131        if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
 132                return;
 133        page_key_rp = page_key_rp->next;
 134        page_key_rx = 0;
 135}
 136
 137int pfn_is_nosave(unsigned long pfn)
 138{
 139        unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
 140        unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
 141        unsigned long eshared_pfn = PFN_DOWN(__pa(&_eshared)) - 1;
 142        unsigned long stext_pfn = PFN_DOWN(__pa(&_stext));
 143
 144        /* Always save lowcore pages (LC protection might be enabled). */
 145        if (pfn <= LC_PAGES)
 146                return 0;
 147        if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
 148                return 1;
 149        /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
 150        if (pfn >= stext_pfn && pfn <= eshared_pfn)
 151                return ipl_info.type == IPL_TYPE_NSS ? 1 : 0;
 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