1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Suspend support specific for s390.
4 *
5 * Copyright IBM Corp. 2009
6 *
7 * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
8 */
9
10 #include <linux/pfn.h>
11 #include <linux/suspend.h>
12 #include <linux/mm.h>
13 #include <linux/pci.h>
14 #include <asm/ctl_reg.h>
15 #include <asm/ipl.h>
16 #include <asm/cio.h>
17 #include <asm/sections.h>
18 #include "entry.h"
19
20 /*
21 * The restore of the saved pages in an hibernation image will set
22 * the change and referenced bits in the storage key for each page.
23 * Overindication of the referenced bits after an hibernation cycle
24 * does not cause any harm but the overindication of the change bits
25 * would cause trouble.
26 * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
27 * page to the most significant byte of the associated page frame
28 * number in the hibernation image.
29 */
30
31 /*
32 * Key storage is allocated as a linked list of pages.
33 * The size of the keys array is (PAGE_SIZE - sizeof(long))
34 */
35 struct page_key_data {
36 struct page_key_data *next;
37 unsigned char data[];
38 };
39
40 #define PAGE_KEY_DATA_SIZE (PAGE_SIZE - sizeof(struct page_key_data *))
41
42 static struct page_key_data *page_key_data;
43 static struct page_key_data *page_key_rp, *page_key_wp;
44 static unsigned long page_key_rx, page_key_wx;
45 unsigned long suspend_zero_pages;
46
47 /*
48 * For each page in the hibernation image one additional byte is
49 * stored in the most significant byte of the page frame number.
50 * On suspend no additional memory is required but on resume the
51 * keys need to be memorized until the page data has been restored.
52 * Only then can the storage keys be set to their old state.
53 */
page_key_additional_pages(unsigned long pages)54 unsigned long page_key_additional_pages(unsigned long pages)
55 {
56 return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
57 }
58
59 /*
60 * Free page_key_data list of arrays.
61 */
page_key_free(void)62 void page_key_free(void)
63 {
64 struct page_key_data *pkd;
65
66 while (page_key_data) {
67 pkd = page_key_data;
68 page_key_data = pkd->next;
69 free_page((unsigned long) pkd);
70 }
71 }
72
73 /*
74 * Allocate page_key_data list of arrays with enough room to store
75 * one byte for each page in the hibernation image.
76 */
page_key_alloc(unsigned long pages)77 int page_key_alloc(unsigned long pages)
78 {
79 struct page_key_data *pk;
80 unsigned long size;
81
82 size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
83 while (size--) {
84 pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
85 if (!pk) {
86 page_key_free();
87 return -ENOMEM;
88 }
89 pk->next = page_key_data;
90 page_key_data = pk;
91 }
92 page_key_rp = page_key_wp = page_key_data;
93 page_key_rx = page_key_wx = 0;
94 return 0;
95 }
96
97 /*
98 * Save the storage key into the upper 8 bits of the page frame number.
99 */
page_key_read(unsigned long * pfn)100 void page_key_read(unsigned long *pfn)
101 {
102 struct page *page;
103 unsigned long addr;
104 unsigned char key;
105
106 page = pfn_to_page(*pfn);
107 addr = (unsigned long) page_address(page);
108 key = (unsigned char) page_get_storage_key(addr) & 0x7f;
109 if (arch_test_page_nodat(page))
110 key |= 0x80;
111 *(unsigned char *) pfn = key;
112 }
113
114 /*
115 * Extract the storage key from the upper 8 bits of the page frame number
116 * and store it in the page_key_data list of arrays.
117 */
page_key_memorize(unsigned long * pfn)118 void page_key_memorize(unsigned long *pfn)
119 {
120 page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
121 *(unsigned char *) pfn = 0;
122 if (++page_key_wx < PAGE_KEY_DATA_SIZE)
123 return;
124 page_key_wp = page_key_wp->next;
125 page_key_wx = 0;
126 }
127
128 /*
129 * Get the next key from the page_key_data list of arrays and set the
130 * storage key of the page referred by @address. If @address refers to
131 * a "safe" page the swsusp_arch_resume code will transfer the storage
132 * key from the buffer page to the original page.
133 */
page_key_write(void * address)134 void page_key_write(void *address)
135 {
136 struct page *page;
137 unsigned char key;
138
139 key = page_key_rp->data[page_key_rx];
140 page_set_storage_key((unsigned long) address, key & 0x7f, 0);
141 page = virt_to_page(address);
142 if (key & 0x80)
143 arch_set_page_nodat(page, 0);
144 else
145 arch_set_page_dat(page, 0);
146 if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
147 return;
148 page_key_rp = page_key_rp->next;
149 page_key_rx = 0;
150 }
151
pfn_is_nosave(unsigned long pfn)152 int pfn_is_nosave(unsigned long pfn)
153 {
154 unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
155 unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
156 unsigned long end_rodata_pfn = PFN_DOWN(__pa(__end_rodata)) - 1;
157 unsigned long stext_pfn = PFN_DOWN(__pa(_stext));
158
159 /* Always save lowcore pages (LC protection might be enabled). */
160 if (pfn <= LC_PAGES)
161 return 0;
162 if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
163 return 1;
164 /* Skip memory holes and read-only pages (DCSS, ...). */
165 if (pfn >= stext_pfn && pfn <= end_rodata_pfn)
166 return 0;
167 if (tprot(PFN_PHYS(pfn)))
168 return 1;
169 return 0;
170 }
171
172 /*
173 * PM notifier callback for suspend
174 */
suspend_pm_cb(struct notifier_block * nb,unsigned long action,void * ptr)175 static int suspend_pm_cb(struct notifier_block *nb, unsigned long action,
176 void *ptr)
177 {
178 switch (action) {
179 case PM_SUSPEND_PREPARE:
180 case PM_HIBERNATION_PREPARE:
181 suspend_zero_pages = __get_free_pages(GFP_KERNEL, LC_ORDER);
182 if (!suspend_zero_pages)
183 return NOTIFY_BAD;
184 break;
185 case PM_POST_SUSPEND:
186 case PM_POST_HIBERNATION:
187 free_pages(suspend_zero_pages, LC_ORDER);
188 break;
189 default:
190 return NOTIFY_DONE;
191 }
192 return NOTIFY_OK;
193 }
194
suspend_pm_init(void)195 static int __init suspend_pm_init(void)
196 {
197 pm_notifier(suspend_pm_cb, 0);
198 return 0;
199 }
200 arch_initcall(suspend_pm_init);
201
save_processor_state(void)202 void save_processor_state(void)
203 {
204 /* swsusp_arch_suspend() actually saves all cpu register contents.
205 * Machine checks must be disabled since swsusp_arch_suspend() stores
206 * register contents to their lowcore save areas. That's the same
207 * place where register contents on machine checks would be saved.
208 * To avoid register corruption disable machine checks.
209 * We must also disable machine checks in the new psw mask for
210 * program checks, since swsusp_arch_suspend() may generate program
211 * checks. Disabling machine checks for all other new psw masks is
212 * just paranoia.
213 */
214 local_mcck_disable();
215 /* Disable lowcore protection */
216 __ctl_clear_bit(0,28);
217 S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
218 S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
219 S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
220 S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
221 }
222
restore_processor_state(void)223 void restore_processor_state(void)
224 {
225 S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
226 S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
227 S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
228 S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
229 /* Enable lowcore protection */
230 __ctl_set_bit(0,28);
231 local_mcck_enable();
232 }
233
234 /* Called at the end of swsusp_arch_resume */
s390_early_resume(void)235 void s390_early_resume(void)
236 {
237 lgr_info_log();
238 channel_subsystem_reinit();
239 zpci_rescan();
240 }
241