]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - arch/x86/kernel/machine_kexec_64.c
x86, kexec: fix crashdump panic with CONFIG_KEXEC_JUMP
[linux-2.6.git] / arch / x86 / kernel / machine_kexec_64.c
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