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
14 /*
15 * References to section boundaries
16 */
17 extern const void __nosave_begin, __nosave_end;
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
45 /*
46 * For each page in the hibernation image one additional byte is
47 * stored in the most significant byte of the page frame number.
48 * On suspend no additional memory is required but on resume the
49 * keys need to be memorized until the page data has been restored.
50 * Only then can the storage keys be set to their old state.
51 */
page_key_additional_pages(unsigned long pages)52 unsigned long page_key_additional_pages(unsigned long pages)
53 {
54 return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
55 }
56
57 /*
58 * Free page_key_data list of arrays.
59 */
page_key_free(void)60 void page_key_free(void)
61 {
62 struct page_key_data *pkd;
63
64 while (page_key_data) {
65 pkd = page_key_data;
66 page_key_data = pkd->next;
67 free_page((unsigned long) pkd);
68 }
69 }
70
71 /*
72 * Allocate page_key_data list of arrays with enough room to store
73 * one byte for each page in the hibernation image.
74 */
page_key_alloc(unsigned long pages)75 int page_key_alloc(unsigned long pages)
76 {
77 struct page_key_data *pk;
78 unsigned long size;
79
80 size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
81 while (size--) {
82 pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
83 if (!pk) {
84 page_key_free();
85 return -ENOMEM;
86 }
87 pk->next = page_key_data;
88 page_key_data = pk;
89 }
90 page_key_rp = page_key_wp = page_key_data;
91 page_key_rx = page_key_wx = 0;
92 return 0;
93 }
94
95 /*
96 * Save the storage key into the upper 8 bits of the page frame number.
97 */
page_key_read(unsigned long * pfn)98 void page_key_read(unsigned long *pfn)
99 {
100 unsigned long addr;
101
102 addr = (unsigned long) page_address(pfn_to_page(*pfn));
103 *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
104 }
105
106 /*
107 * Extract the storage key from the upper 8 bits of the page frame number
108 * and store it in the page_key_data list of arrays.
109 */
page_key_memorize(unsigned long * pfn)110 void page_key_memorize(unsigned long *pfn)
111 {
112 page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
113 *(unsigned char *) pfn = 0;
114 if (++page_key_wx < PAGE_KEY_DATA_SIZE)
115 return;
116 page_key_wp = page_key_wp->next;
117 page_key_wx = 0;
118 }
119
120 /*
121 * Get the next key from the page_key_data list of arrays and set the
122 * storage key of the page referred by @address. If @address refers to
123 * a "safe" page the swsusp_arch_resume code will transfer the storage
124 * key from the buffer page to the original page.
125 */
page_key_write(void * address)126 void page_key_write(void *address)
127 {
128 page_set_storage_key((unsigned long) address,
129 page_key_rp->data[page_key_rx], 0);
130 if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
131 return;
132 page_key_rp = page_key_rp->next;
133 page_key_rx = 0;
134 }
135
pfn_is_nosave(unsigned long pfn)136 int pfn_is_nosave(unsigned long pfn)
137 {
138 unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
139 unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
140
141 /* Always save lowcore pages (LC protection might be enabled). */
142 if (pfn <= LC_PAGES)
143 return 0;
144 if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
145 return 1;
146 /* Skip memory holes and read-only pages (NSS, DCSS, ...). */
147 if (tprot(PFN_PHYS(pfn)))
148 return 1;
149 return 0;
150 }
151
save_processor_state(void)152 void save_processor_state(void)
153 {
154 /* swsusp_arch_suspend() actually saves all cpu register contents.
155 * Machine checks must be disabled since swsusp_arch_suspend() stores
156 * register contents to their lowcore save areas. That's the same
157 * place where register contents on machine checks would be saved.
158 * To avoid register corruption disable machine checks.
159 * We must also disable machine checks in the new psw mask for
160 * program checks, since swsusp_arch_suspend() may generate program
161 * checks. Disabling machine checks for all other new psw masks is
162 * just paranoia.
163 */
164 local_mcck_disable();
165 /* Disable lowcore protection */
166 __ctl_clear_bit(0,28);
167 S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
168 S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
169 S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
170 S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
171 }
172
restore_processor_state(void)173 void restore_processor_state(void)
174 {
175 S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
176 S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
177 S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
178 S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
179 /* Enable lowcore protection */
180 __ctl_set_bit(0,28);
181 local_mcck_enable();
182 }
183