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 */
34 struct 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
41 static struct page_key_data *page_key_data;
42 static struct page_key_data *page_key_rp, *page_key_wp;
43 static unsigned long page_key_rx, page_key_wx;
44 unsigned 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 */
page_key_additional_pages(unsigned long pages)53 unsigned 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 */
page_key_free(void)61 void 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 */
page_key_alloc(unsigned long pages)76 int 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 */
page_key_read(unsigned long * pfn)99 void 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 */
page_key_memorize(unsigned long * pfn)111 void 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 */
page_key_write(void * address)127 void 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
pfn_is_nosave(unsigned long pfn)137 int 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 */
suspend_pm_cb(struct notifier_block * nb,unsigned long action,void * ptr)160 static 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
suspend_pm_init(void)180 static int __init suspend_pm_init(void)
181 {
182 pm_notifier(suspend_pm_cb, 0);
183 return 0;
184 }
185 arch_initcall(suspend_pm_init);
186
save_processor_state(void)187 void 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
restore_processor_state(void)208 void 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 */
s390_early_resume(void)220 void s390_early_resume(void)
221 {
222 lgr_info_log();
223 channel_subsystem_reinit();
224 zpci_rescan();
225 }
226