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 <asm/pgtable.h>
15 #include <asm/tlbflush.h>
16 #include <asm/mmu_context.h>
17 #include <asm/io.h>
18
19 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
20 static u64 kexec_pgd[512] PAGE_ALIGNED;
21 static u64 kexec_pud0[512] PAGE_ALIGNED;
22 static u64 kexec_pmd0[512] PAGE_ALIGNED;
23 static u64 kexec_pte0[512] PAGE_ALIGNED;
24 static u64 kexec_pud1[512] PAGE_ALIGNED;
25 static u64 kexec_pmd1[512] PAGE_ALIGNED;
26 static u64 kexec_pte1[512] PAGE_ALIGNED;
27
28 static void init_level2_page(pmd_t *level2p, unsigned long addr)
29 {
30 unsigned long end_addr;
31
32 addr &= PAGE_MASK;
33 end_addr = addr + PUD_SIZE;
34 while (addr < end_addr) {
35 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
36 addr += PMD_SIZE;
37 }
38 }
39
40 static int init_level3_page(struct kimage *image, pud_t *level3p,
41 unsigned long addr, unsigned long last_addr)
42 {
43 unsigned long end_addr;
44 int result;
45
46 result = 0;
47 addr &= PAGE_MASK;
48 end_addr = addr + PGDIR_SIZE;
49 while ((addr < last_addr) && (addr < end_addr)) {
50 struct page *page;
51 pmd_t *level2p;
52
53 page = kimage_alloc_control_pages(image, 0);
54 if (!page) {
55 result = -ENOMEM;
56 goto out;
57 }
58 level2p = (pmd_t *)page_address(page);
59 init_level2_page(level2p, addr);
60 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
61 addr += PUD_SIZE;
62 }
63 /* clear the unused entries */
64 while (addr < end_addr) {
65 pud_clear(level3p++);
66 addr += PUD_SIZE;
67 }
68 out:
69 return result;
70 }
71
72
73 static int init_level4_page(struct kimage *image, pgd_t *level4p,
74 unsigned long addr, unsigned long last_addr)
75 {
76 unsigned long end_addr;
77 int result;
78
79 result = 0;
80 addr &= PAGE_MASK;
81 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
82 while ((addr < last_addr) && (addr < end_addr)) {
83 struct page *page;
84 pud_t *level3p;
85
86 page = kimage_alloc_control_pages(image, 0);
87 if (!page) {
88 result = -ENOMEM;
89 goto out;
90 }
91 level3p = (pud_t *)page_address(page);
92 result = init_level3_page(image, level3p, addr, last_addr);
93 if (result) {
94 goto out;
95 }
96 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
97 addr += PGDIR_SIZE;
98 }
99 /* clear the unused entries */
100 while (addr < end_addr) {
101 pgd_clear(level4p++);
102 addr += PGDIR_SIZE;
103 }
104 out:
105 return result;
106 }
107
108
109 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
110 {
111 pgd_t *level4p;
112 level4p = (pgd_t *)__va(start_pgtable);
113 return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
114 }
115
116 static void set_idt(void *newidt, u16 limit)
117 {
118 struct desc_ptr curidt;
119
120 /* x86-64 supports unaliged loads & stores */
121 curidt.size = limit;
122 curidt.address = (unsigned long)newidt;
123
124 __asm__ __volatile__ (
125 "lidtq %0\n"
126 : : "m" (curidt)
127 );
128 };
129
130
131 static void set_gdt(void *newgdt, u16 limit)
132 {
133 struct desc_ptr curgdt;
134
135 /* x86-64 supports unaligned loads & stores */
136 curgdt.size = limit;
137 curgdt.address = (unsigned long)newgdt;
138
139 __asm__ __volatile__ (
140 "lgdtq %0\n"
141 : : "m" (curgdt)
142 );
143 };
144
145 static void load_segments(void)
146 {
147 __asm__ __volatile__ (
148 "\tmovl %0,%%ds\n"
149 "\tmovl %0,%%es\n"
150 "\tmovl %0,%%ss\n"
151 "\tmovl %0,%%fs\n"
152 "\tmovl %0,%%gs\n"
153 : : "a" (__KERNEL_DS) : "memory"
154 );
155 }
156
157 int machine_kexec_prepare(struct kimage *image)
158 {
159 unsigned long start_pgtable;
160 int result;
161
162 /* Calculate the offsets */
163 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
164
165 /* Setup the identity mapped 64bit page table */
166 result = init_pgtable(image, start_pgtable);
167 if (result)
168 return result;
169
170 return 0;
171 }
172
173 void machine_kexec_cleanup(struct kimage *image)
174 {
175 return;
176 }
177
178 /*
179 * Do not allocate memory (or fail in any way) in machine_kexec().
180 * We are past the point of no return, committed to rebooting now.
181 */
182 NORET_TYPE void machine_kexec(struct kimage *image)
183 {
184 unsigned long page_list[PAGES_NR];
185 void *control_page;
186
187 /* Interrupts aren't acceptable while we reboot */
188 local_irq_disable();
189
190 control_page = page_address(image->control_code_page) + PAGE_SIZE;
191 memcpy(control_page, relocate_kernel, PAGE_SIZE);
192
193 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
194 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel;
195 page_list[PA_PGD] = virt_to_phys(&kexec_pgd);
196 page_list[VA_PGD] = (unsigned long)kexec_pgd;
197 page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0);
198 page_list[VA_PUD_0] = (unsigned long)kexec_pud0;
199 page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0);
200 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
201 page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0);
202 page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
203 page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1);
204 page_list[VA_PUD_1] = (unsigned long)kexec_pud1;
205 page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1);
206 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
207 page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1);
208 page_list[VA_PTE_1] = (unsigned long)kexec_pte1;
209
210 page_list[PA_TABLE_PAGE] =
211 (unsigned long)__pa(page_address(image->control_code_page));
212
213 /* The segment registers are funny things, they have both a
214 * visible and an invisible part. Whenever the visible part is
215 * set to a specific selector, the invisible part is loaded
216 * with from a table in memory. At no other time is the
217 * descriptor table in memory accessed.
218 *
219 * I take advantage of this here by force loading the
220 * segments, before I zap the gdt with an invalid value.
221 */
222 load_segments();
223 /* The gdt & idt are now invalid.
224 * If you want to load them you must set up your own idt & gdt.
225 */
226 set_gdt(phys_to_virt(0),0);
227 set_idt(phys_to_virt(0),0);
228
229 /* now call it */
230 relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
231 image->start);
232 }
233
234 void arch_crash_save_vmcoreinfo(void)
235 {
236 VMCOREINFO_SYMBOL(phys_base);
237 VMCOREINFO_SYMBOL(init_level4_pgt);
238
239 #ifdef CONFIG_NUMA
240 VMCOREINFO_SYMBOL(node_data);
241 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
242 #endif
243 }
244
245
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