1 /*
2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8
9 #include <linux/mm.h>
10 #include <linux/kexec.h>
11 #include <linux/string.h>
12 #include <linux/reboot.h>
13 #include <linux/numa.h>
14 #include <linux/ftrace.h>
15 #include <linux/io.h>
16 #include <linux/suspend.h>
17
18 #include <asm/pgtable.h>
19 #include <asm/tlbflush.h>
20 #include <asm/mmu_context.h>
21
22 static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
23 unsigned long addr)
24 {
25 pud_t *pud;
26 pmd_t *pmd;
27 struct page *page;
28 int result = -ENOMEM;
29
30 addr &= PMD_MASK;
31 pgd += pgd_index(addr);
32 if (!pgd_present(*pgd)) {
33 page = kimage_alloc_control_pages(image, 0);
34 if (!page)
35 goto out;
36 pud = (pud_t *)page_address(page);
37 memset(pud, 0, PAGE_SIZE);
38 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
39 }
40 pud = pud_offset(pgd, addr);
41 if (!pud_present(*pud)) {
42 page = kimage_alloc_control_pages(image, 0);
43 if (!page)
44 goto out;
45 pmd = (pmd_t *)page_address(page);
46 memset(pmd, 0, PAGE_SIZE);
47 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
48 }
49 pmd = pmd_offset(pud, addr);
50 if (!pmd_present(*pmd))
51 set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
52 result = 0;
53 out:
54 return result;
55 }
56
57 static void init_level2_page(pmd_t *level2p, unsigned long addr)
58 {
59 unsigned long end_addr;
60
61 addr &= PAGE_MASK;
62 end_addr = addr + PUD_SIZE;
63 while (addr < end_addr) {
64 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
65 addr += PMD_SIZE;
66 }
67 }
68
69 static int init_level3_page(struct kimage *image, pud_t *level3p,
70 unsigned long addr, unsigned long last_addr)
71 {
72 unsigned long end_addr;
73 int result;
74
75 result = 0;
76 addr &= PAGE_MASK;
77 end_addr = addr + PGDIR_SIZE;
78 while ((addr < last_addr) && (addr < end_addr)) {
79 struct page *page;
80 pmd_t *level2p;
81
82 page = kimage_alloc_control_pages(image, 0);
83 if (!page) {
84 result = -ENOMEM;
85 goto out;
86 }
87 level2p = (pmd_t *)page_address(page);
88 init_level2_page(level2p, addr);
89 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
90 addr += PUD_SIZE;
91 }
92 /* clear the unused entries */
93 while (addr < end_addr) {
94 pud_clear(level3p++);
95 addr += PUD_SIZE;
96 }
97 out:
98 return result;
99 }
100
101
102 static int init_level4_page(struct kimage *image, pgd_t *level4p,
103 unsigned long addr, unsigned long last_addr)
104 {
105 unsigned long end_addr;
106 int result;
107
108 result = 0;
109 addr &= PAGE_MASK;
110 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
111 while ((addr < last_addr) && (addr < end_addr)) {
112 struct page *page;
113 pud_t *level3p;
114
115 page = kimage_alloc_control_pages(image, 0);
116 if (!page) {
117 result = -ENOMEM;
118 goto out;
119 }
120 level3p = (pud_t *)page_address(page);
121 result = init_level3_page(image, level3p, addr, last_addr);
122 if (result)
123 goto out;
124 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
125 addr += PGDIR_SIZE;
126 }
127 /* clear the unused entries */
128 while (addr < end_addr) {
129 pgd_clear(level4p++);
130 addr += PGDIR_SIZE;
131 }
132 out:
133 return result;
134 }
135
136 static void free_transition_pgtable(struct kimage *image)
137 {
138 free_page((unsigned long)image->arch.pud);
139 free_page((unsigned long)image->arch.pmd);
140 free_page((unsigned long)image->arch.pte);
141 }
142
143 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
144 {
145 pud_t *pud;
146 pmd_t *pmd;
147 pte_t *pte;
148 unsigned long vaddr, paddr;
149 int result = -ENOMEM;
150
151 vaddr = (unsigned long)relocate_kernel;
152 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
153 pgd += pgd_index(vaddr);
154 if (!pgd_present(*pgd)) {
155 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
156 if (!pud)
157 goto err;
158 image->arch.pud = pud;
159 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
160 }
161 pud = pud_offset(pgd, vaddr);
162 if (!pud_present(*pud)) {
163 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
164 if (!pmd)
165 goto err;
166 image->arch.pmd = pmd;
167 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
168 }
169 pmd = pmd_offset(pud, vaddr);
170 if (!pmd_present(*pmd)) {
171 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
172 if (!pte)
173 goto err;
174 image->arch.pte = pte;
175 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
176 }
177 pte = pte_offset_kernel(pmd, vaddr);
178 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
179 return 0;
180 err:
181 free_transition_pgtable(image);
182 return result;
183 }
184
185
186 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
187 {
188 pgd_t *level4p;
189 int result;
190 level4p = (pgd_t *)__va(start_pgtable);
191 result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
192 if (result)
193 return result;
194 /*
195 * image->start may be outside 0 ~ max_pfn, for example when
196 * jump back to original kernel from kexeced kernel
197 */
198 result = init_one_level2_page(image, level4p, image->start);
199 if (result)
200 return result;
201 return init_transition_pgtable(image, level4p);
202 }
203
204 static void set_idt(void *newidt, u16 limit)
205 {
206 struct desc_ptr curidt;
207
208 /* x86-64 supports unaliged loads & stores */
209 curidt.size = limit;
210 curidt.address = (unsigned long)newidt;
211
212 __asm__ __volatile__ (
213 "lidtq %0\n"
214 : : "m" (curidt)
215 );
216 };
217
218
219 static void set_gdt(void *newgdt, u16 limit)
220 {
221 struct desc_ptr curgdt;
222
223 /* x86-64 supports unaligned loads & stores */
224 curgdt.size = limit;
225 curgdt.address = (unsigned long)newgdt;
226
227 __asm__ __volatile__ (
228 "lgdtq %0\n"
229 : : "m" (curgdt)
230 );
231 };
232
233 static void load_segments(void)
234 {
235 __asm__ __volatile__ (
236 "\tmovl %0,%%ds\n"
237 "\tmovl %0,%%es\n"
238 "\tmovl %0,%%ss\n"
239 "\tmovl %0,%%fs\n"
240 "\tmovl %0,%%gs\n"
241 : : "a" (__KERNEL_DS) : "memory"
242 );
243 }
244
245 int machine_kexec_prepare(struct kimage *image)
246 {
247 unsigned long start_pgtable;
248 int result;
249
250 /* Calculate the offsets */
251 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
252
253 /* Setup the identity mapped 64bit page table */
254 result = init_pgtable(image, start_pgtable);
255 if (result)
256 return result;
257
258 return 0;
259 }
260
261 void machine_kexec_cleanup(struct kimage *image)
262 {
263 free_transition_pgtable(image);
264 }
265
266 /*
267 * Do not allocate memory (or fail in any way) in machine_kexec().
268 * We are past the point of no return, committed to rebooting now.
269 */
270 void machine_kexec(struct kimage *image)
271 {
272 unsigned long page_list[PAGES_NR];
273 void *control_page;
274 int save_ftrace_enabled;
275
276 #ifdef CONFIG_KEXEC_JUMP
277 if (image->preserve_context)
278 save_processor_state();
279 #endif
280
281 save_ftrace_enabled = __ftrace_enabled_save();
282
283 /* Interrupts aren't acceptable while we reboot */
284 local_irq_disable();
285
286 if (image->preserve_context) {
287 #ifdef CONFIG_X86_IO_APIC
288 /*
289 * We need to put APICs in legacy mode so that we can
290 * get timer interrupts in second kernel. kexec/kdump
291 * paths already have calls to disable_IO_APIC() in
292 * one form or other. kexec jump path also need
293 * one.
294 */
295 disable_IO_APIC();
296 #endif
297 }
298
299 control_page = page_address(image->control_code_page) + PAGE_SIZE;
300 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
301
302 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
303 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
304 page_list[PA_TABLE_PAGE] =
305 (unsigned long)__pa(page_address(image->control_code_page));
306
307 if (image->type == KEXEC_TYPE_DEFAULT)
308 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
309 << PAGE_SHIFT);
310
311 /*
312 * The segment registers are funny things, they have both a
313 * visible and an invisible part. Whenever the visible part is
314 * set to a specific selector, the invisible part is loaded
315 * with from a table in memory. At no other time is the
316 * descriptor table in memory accessed.
317 *
318 * I take advantage of this here by force loading the
319 * segments, before I zap the gdt with an invalid value.
320 */
321 load_segments();
322 /*
323 * The gdt & idt are now invalid.
324 * If you want to load them you must set up your own idt & gdt.
325 */
326 set_gdt(phys_to_virt(0), 0);
327 set_idt(phys_to_virt(0), 0);
328
329 /* now call it */
330 image->start = relocate_kernel((unsigned long)image->head,
331 (unsigned long)page_list,
332 image->start,
333 image->preserve_context);
334
335 #ifdef CONFIG_KEXEC_JUMP
336 if (image->preserve_context)
337 restore_processor_state();
338 #endif
339
340 __ftrace_enabled_restore(save_ftrace_enabled);
341 }
342
343 void arch_crash_save_vmcoreinfo(void)
344 {
345 VMCOREINFO_SYMBOL(phys_base);
346 VMCOREINFO_SYMBOL(init_level4_pgt);
347
348 #ifdef CONFIG_NUMA
349 VMCOREINFO_SYMBOL(node_data);
350 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
351 #endif
352 }
353
354
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