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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 <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