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/delay.h>
12 #include <linux/init.h>
13 #include <linux/numa.h>
14 #include <linux/ftrace.h>
15 #include <linux/suspend.h>
16 #include <linux/gfp.h>
17 #include <linux/io.h>
18
19 #include <asm/pgtable.h>
20 #include <asm/pgalloc.h>
21 #include <asm/tlbflush.h>
22 #include <asm/mmu_context.h>
23 #include <asm/apic.h>
24 #include <asm/cpufeature.h>
25 #include <asm/desc.h>
26 #include <asm/system.h>
27 #include <asm/cacheflush.h>
28
29 static void set_idt(void *newidt, __u16 limit)
30 {
31 struct desc_ptr curidt;
32
33 /* ia32 supports unaliged loads & stores */
34 curidt.size = limit;
35 curidt.address = (unsigned long)newidt;
36
37 load_idt(&curidt);
38 }
39
40
41 static void set_gdt(void *newgdt, __u16 limit)
42 {
43 struct desc_ptr curgdt;
44
45 /* ia32 supports unaligned loads & stores */
46 curgdt.size = limit;
47 curgdt.address = (unsigned long)newgdt;
48
49 load_gdt(&curgdt);
50 }
51
52 static void load_segments(void)
53 {
54 #define __STR(X) #X
55 #define STR(X) __STR(X)
56
57 __asm__ __volatile__ (
58 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
59 "\t1:\n"
60 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
61 "\tmovl %%eax,%%ds\n"
62 "\tmovl %%eax,%%es\n"
63 "\tmovl %%eax,%%fs\n"
64 "\tmovl %%eax,%%gs\n"
65 "\tmovl %%eax,%%ss\n"
66 : : : "eax", "memory");
67 #undef STR
68 #undef __STR
69 }
70
71 static void machine_kexec_free_page_tables(struct kimage *image)
72 {
73 free_page((unsigned long)image->arch.pgd);
74 #ifdef CONFIG_X86_PAE
75 free_page((unsigned long)image->arch.pmd0);
76 free_page((unsigned long)image->arch.pmd1);
77 #endif
78 free_page((unsigned long)image->arch.pte0);
79 free_page((unsigned long)image->arch.pte1);
80 }
81
82 static int machine_kexec_alloc_page_tables(struct kimage *image)
83 {
84 image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
85 #ifdef CONFIG_X86_PAE
86 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
87 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
88 #endif
89 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
90 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
91 if (!image->arch.pgd ||
92 #ifdef CONFIG_X86_PAE
93 !image->arch.pmd0 || !image->arch.pmd1 ||
94 #endif
95 !image->arch.pte0 || !image->arch.pte1) {
96 machine_kexec_free_page_tables(image);
97 return -ENOMEM;
98 }
99 return 0;
100 }
101
102 static void machine_kexec_page_table_set_one(
103 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
104 unsigned long vaddr, unsigned long paddr)
105 {
106 pud_t *pud;
107
108 pgd += pgd_index(vaddr);
109 #ifdef CONFIG_X86_PAE
110 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
111 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
112 #endif
113 pud = pud_offset(pgd, vaddr);
114 pmd = pmd_offset(pud, vaddr);
115 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
116 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
117 pte = pte_offset_kernel(pmd, vaddr);
118 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
119 }
120
121 static void machine_kexec_prepare_page_tables(struct kimage *image)
122 {
123 void *control_page;
124 pmd_t *pmd = NULL;
125
126 control_page = page_address(image->control_code_page);
127 #ifdef CONFIG_X86_PAE
128 pmd = image->arch.pmd0;
129 #endif
130 machine_kexec_page_table_set_one(
131 image->arch.pgd, pmd, image->arch.pte0,
132 (unsigned long)control_page, __pa(control_page));
133 #ifdef CONFIG_X86_PAE
134 pmd = image->arch.pmd1;
135 #endif
136 machine_kexec_page_table_set_one(
137 image->arch.pgd, pmd, image->arch.pte1,
138 __pa(control_page), __pa(control_page));
139 }
140
141 /*
142 * A architecture hook called to validate the
143 * proposed image and prepare the control pages
144 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
145 * have been allocated, but the segments have yet
146 * been copied into the kernel.
147 *
148 * Do what every setup is needed on image and the
149 * reboot code buffer to allow us to avoid allocations
150 * later.
151 *
152 * - Make control page executable.
153 * - Allocate page tables
154 * - Setup page tables
155 */
156 int machine_kexec_prepare(struct kimage *image)
157 {
158 int error;
159
160 if (nx_enabled)
161 set_pages_x(image->control_code_page, 1);
162 error = machine_kexec_alloc_page_tables(image);
163 if (error)
164 return error;
165 machine_kexec_prepare_page_tables(image);
166 return 0;
167 }
168
169 /*
170 * Undo anything leftover by machine_kexec_prepare
171 * when an image is freed.
172 */
173 void machine_kexec_cleanup(struct kimage *image)
174 {
175 if (nx_enabled)
176 set_pages_nx(image->control_code_page, 1);
177 machine_kexec_free_page_tables(image);
178 }
179
180 /*
181 * Do not allocate memory (or fail in any way) in machine_kexec().
182 * We are past the point of no return, committed to rebooting now.
183 */
184 void machine_kexec(struct kimage *image)
185 {
186 unsigned long page_list[PAGES_NR];
187 void *control_page;
188 int save_ftrace_enabled;
189 asmlinkage unsigned long
190 (*relocate_kernel_ptr)(unsigned long indirection_page,
191 unsigned long control_page,
192 unsigned long start_address,
193 unsigned int has_pae,
194 unsigned int preserve_context);
195
196 #ifdef CONFIG_KEXEC_JUMP
197 if (image->preserve_context)
198 save_processor_state();
199 #endif
200
201 save_ftrace_enabled = __ftrace_enabled_save();
202
203 /* Interrupts aren't acceptable while we reboot */
204 local_irq_disable();
205
206 if (image->preserve_context) {
207 #ifdef CONFIG_X86_IO_APIC
208 /*
209 * We need to put APICs in legacy mode so that we can
210 * get timer interrupts in second kernel. kexec/kdump
211 * paths already have calls to disable_IO_APIC() in
212 * one form or other. kexec jump path also need
213 * one.
214 */
215 disable_IO_APIC();
216 #endif
217 }
218
219 control_page = page_address(image->control_code_page);
220 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
221
222 relocate_kernel_ptr = control_page;
223 page_list[PA_CONTROL_PAGE] = __pa(control_page);
224 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
225 page_list[PA_PGD] = __pa(image->arch.pgd);
226
227 if (image->type == KEXEC_TYPE_DEFAULT)
228 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
229 << PAGE_SHIFT);
230
231 /*
232 * The segment registers are funny things, they have both a
233 * visible and an invisible part. Whenever the visible part is
234 * set to a specific selector, the invisible part is loaded
235 * with from a table in memory. At no other time is the
236 * descriptor table in memory accessed.
237 *
238 * I take advantage of this here by force loading the
239 * segments, before I zap the gdt with an invalid value.
240 */
241 load_segments();
242 /*
243 * The gdt & idt are now invalid.
244 * If you want to load them you must set up your own idt & gdt.
245 */
246 set_gdt(phys_to_virt(0), 0);
247 set_idt(phys_to_virt(0), 0);
248
249 /* now call it */
250 image->start = relocate_kernel_ptr((unsigned long)image->head,
251 (unsigned long)page_list,
252 image->start, cpu_has_pae,
253 image->preserve_context);
254
255 #ifdef CONFIG_KEXEC_JUMP
256 if (image->preserve_context)
257 restore_processor_state();
258 #endif
259
260 __ftrace_enabled_restore(save_ftrace_enabled);
261 }
262
263 void arch_crash_save_vmcoreinfo(void)
264 {
265 #ifdef CONFIG_NUMA
266 VMCOREINFO_SYMBOL(node_data);
267 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
268 #endif
269 #ifdef CONFIG_X86_PAE
270 VMCOREINFO_CONFIG(X86_PAE);
271 #endif
272 }
273
274
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