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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * handle transition of Linux booting another kernel
4 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
5 */
6
7#include <linux/mm.h>
8#include <linux/kexec.h>
9#include <linux/delay.h>
10#include <linux/numa.h>
11#include <linux/ftrace.h>
12#include <linux/suspend.h>
13#include <linux/gfp.h>
14#include <linux/io.h>
15
16#include <asm/pgalloc.h>
17#include <asm/tlbflush.h>
18#include <asm/mmu_context.h>
19#include <asm/apic.h>
20#include <asm/io_apic.h>
21#include <asm/cpufeature.h>
22#include <asm/desc.h>
23#include <asm/set_memory.h>
24#include <asm/debugreg.h>
25
26static void load_segments(void)
27{
28#define __STR(X) #X
29#define STR(X) __STR(X)
30
31 __asm__ __volatile__ (
32 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
33 "\t1:\n"
34 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
35 "\tmovl %%eax,%%ds\n"
36 "\tmovl %%eax,%%es\n"
37 "\tmovl %%eax,%%ss\n"
38 : : : "eax", "memory");
39#undef STR
40#undef __STR
41}
42
43static void machine_kexec_free_page_tables(struct kimage *image)
44{
45 free_pages((unsigned long)image->arch.pgd, PGD_ALLOCATION_ORDER);
46 image->arch.pgd = NULL;
47#ifdef CONFIG_X86_PAE
48 free_page((unsigned long)image->arch.pmd0);
49 image->arch.pmd0 = NULL;
50 free_page((unsigned long)image->arch.pmd1);
51 image->arch.pmd1 = NULL;
52#endif
53 free_page((unsigned long)image->arch.pte0);
54 image->arch.pte0 = NULL;
55 free_page((unsigned long)image->arch.pte1);
56 image->arch.pte1 = NULL;
57}
58
59static int machine_kexec_alloc_page_tables(struct kimage *image)
60{
61 image->arch.pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
62 PGD_ALLOCATION_ORDER);
63#ifdef CONFIG_X86_PAE
64 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
65 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
66#endif
67 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
68 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
69 if (!image->arch.pgd ||
70#ifdef CONFIG_X86_PAE
71 !image->arch.pmd0 || !image->arch.pmd1 ||
72#endif
73 !image->arch.pte0 || !image->arch.pte1) {
74 return -ENOMEM;
75 }
76 return 0;
77}
78
79static void machine_kexec_page_table_set_one(
80 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
81 unsigned long vaddr, unsigned long paddr)
82{
83 p4d_t *p4d;
84 pud_t *pud;
85
86 pgd += pgd_index(vaddr);
87#ifdef CONFIG_X86_PAE
88 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
89 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
90#endif
91 p4d = p4d_offset(pgd, vaddr);
92 pud = pud_offset(p4d, vaddr);
93 pmd = pmd_offset(pud, vaddr);
94 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
95 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
96 pte = pte_offset_kernel(pmd, vaddr);
97 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
98}
99
100static void machine_kexec_prepare_page_tables(struct kimage *image)
101{
102 void *control_page;
103 pmd_t *pmd = NULL;
104
105 control_page = page_address(image->control_code_page);
106#ifdef CONFIG_X86_PAE
107 pmd = image->arch.pmd0;
108#endif
109 machine_kexec_page_table_set_one(
110 image->arch.pgd, pmd, image->arch.pte0,
111 (unsigned long)control_page, __pa(control_page));
112#ifdef CONFIG_X86_PAE
113 pmd = image->arch.pmd1;
114#endif
115 machine_kexec_page_table_set_one(
116 image->arch.pgd, pmd, image->arch.pte1,
117 __pa(control_page), __pa(control_page));
118}
119
120/*
121 * A architecture hook called to validate the
122 * proposed image and prepare the control pages
123 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
124 * have been allocated, but the segments have yet
125 * been copied into the kernel.
126 *
127 * Do what every setup is needed on image and the
128 * reboot code buffer to allow us to avoid allocations
129 * later.
130 *
131 * - Make control page executable.
132 * - Allocate page tables
133 * - Setup page tables
134 */
135int machine_kexec_prepare(struct kimage *image)
136{
137 int error;
138
139 set_memory_x((unsigned long)page_address(image->control_code_page), 1);
140 error = machine_kexec_alloc_page_tables(image);
141 if (error)
142 return error;
143 machine_kexec_prepare_page_tables(image);
144 return 0;
145}
146
147/*
148 * Undo anything leftover by machine_kexec_prepare
149 * when an image is freed.
150 */
151void machine_kexec_cleanup(struct kimage *image)
152{
153 set_memory_nx((unsigned long)page_address(image->control_code_page), 1);
154 machine_kexec_free_page_tables(image);
155}
156
157/*
158 * Do not allocate memory (or fail in any way) in machine_kexec().
159 * We are past the point of no return, committed to rebooting now.
160 */
161void machine_kexec(struct kimage *image)
162{
163 unsigned long page_list[PAGES_NR];
164 void *control_page;
165 int save_ftrace_enabled;
166 asmlinkage unsigned long
167 (*relocate_kernel_ptr)(unsigned long indirection_page,
168 unsigned long control_page,
169 unsigned long start_address,
170 unsigned int has_pae,
171 unsigned int preserve_context);
172
173#ifdef CONFIG_KEXEC_JUMP
174 if (image->preserve_context)
175 save_processor_state();
176#endif
177
178 save_ftrace_enabled = __ftrace_enabled_save();
179
180 /* Interrupts aren't acceptable while we reboot */
181 local_irq_disable();
182 hw_breakpoint_disable();
183
184 if (image->preserve_context) {
185#ifdef CONFIG_X86_IO_APIC
186 /*
187 * We need to put APICs in legacy mode so that we can
188 * get timer interrupts in second kernel. kexec/kdump
189 * paths already have calls to restore_boot_irq_mode()
190 * in one form or other. kexec jump path also need one.
191 */
192 clear_IO_APIC();
193 restore_boot_irq_mode();
194#endif
195 }
196
197 control_page = page_address(image->control_code_page);
198 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
199
200 relocate_kernel_ptr = control_page;
201 page_list[PA_CONTROL_PAGE] = __pa(control_page);
202 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
203 page_list[PA_PGD] = __pa(image->arch.pgd);
204
205 if (image->type == KEXEC_TYPE_DEFAULT)
206 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
207 << PAGE_SHIFT);
208
209 /*
210 * The segment registers are funny things, they have both a
211 * visible and an invisible part. Whenever the visible part is
212 * set to a specific selector, the invisible part is loaded
213 * with from a table in memory. At no other time is the
214 * descriptor table in memory accessed.
215 *
216 * I take advantage of this here by force loading the
217 * segments, before I zap the gdt with an invalid value.
218 */
219 load_segments();
220 /*
221 * The gdt & idt are now invalid.
222 * If you want to load them you must set up your own idt & gdt.
223 */
224 native_idt_invalidate();
225 native_gdt_invalidate();
226
227 /* now call it */
228 image->start = relocate_kernel_ptr((unsigned long)image->head,
229 (unsigned long)page_list,
230 image->start,
231 boot_cpu_has(X86_FEATURE_PAE),
232 image->preserve_context);
233
234#ifdef CONFIG_KEXEC_JUMP
235 if (image->preserve_context)
236 restore_processor_state();
237#endif
238
239 __ftrace_enabled_restore(save_ftrace_enabled);
240}
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#include <asm/debugreg.h>
29
30static void set_idt(void *newidt, __u16 limit)
31{
32 struct desc_ptr curidt;
33
34 /* ia32 supports unaliged loads & stores */
35 curidt.size = limit;
36 curidt.address = (unsigned long)newidt;
37
38 load_idt(&curidt);
39}
40
41
42static void set_gdt(void *newgdt, __u16 limit)
43{
44 struct desc_ptr curgdt;
45
46 /* ia32 supports unaligned loads & stores */
47 curgdt.size = limit;
48 curgdt.address = (unsigned long)newgdt;
49
50 load_gdt(&curgdt);
51}
52
53static void load_segments(void)
54{
55#define __STR(X) #X
56#define STR(X) __STR(X)
57
58 __asm__ __volatile__ (
59 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
60 "\t1:\n"
61 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
62 "\tmovl %%eax,%%ds\n"
63 "\tmovl %%eax,%%es\n"
64 "\tmovl %%eax,%%fs\n"
65 "\tmovl %%eax,%%gs\n"
66 "\tmovl %%eax,%%ss\n"
67 : : : "eax", "memory");
68#undef STR
69#undef __STR
70}
71
72static void machine_kexec_free_page_tables(struct kimage *image)
73{
74 free_page((unsigned long)image->arch.pgd);
75#ifdef CONFIG_X86_PAE
76 free_page((unsigned long)image->arch.pmd0);
77 free_page((unsigned long)image->arch.pmd1);
78#endif
79 free_page((unsigned long)image->arch.pte0);
80 free_page((unsigned long)image->arch.pte1);
81}
82
83static int machine_kexec_alloc_page_tables(struct kimage *image)
84{
85 image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
86#ifdef CONFIG_X86_PAE
87 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
88 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
89#endif
90 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
91 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
92 if (!image->arch.pgd ||
93#ifdef CONFIG_X86_PAE
94 !image->arch.pmd0 || !image->arch.pmd1 ||
95#endif
96 !image->arch.pte0 || !image->arch.pte1) {
97 machine_kexec_free_page_tables(image);
98 return -ENOMEM;
99 }
100 return 0;
101}
102
103static void machine_kexec_page_table_set_one(
104 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
105 unsigned long vaddr, unsigned long paddr)
106{
107 pud_t *pud;
108
109 pgd += pgd_index(vaddr);
110#ifdef CONFIG_X86_PAE
111 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
112 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
113#endif
114 pud = pud_offset(pgd, vaddr);
115 pmd = pmd_offset(pud, vaddr);
116 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
117 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
118 pte = pte_offset_kernel(pmd, vaddr);
119 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
120}
121
122static void machine_kexec_prepare_page_tables(struct kimage *image)
123{
124 void *control_page;
125 pmd_t *pmd = NULL;
126
127 control_page = page_address(image->control_code_page);
128#ifdef CONFIG_X86_PAE
129 pmd = image->arch.pmd0;
130#endif
131 machine_kexec_page_table_set_one(
132 image->arch.pgd, pmd, image->arch.pte0,
133 (unsigned long)control_page, __pa(control_page));
134#ifdef CONFIG_X86_PAE
135 pmd = image->arch.pmd1;
136#endif
137 machine_kexec_page_table_set_one(
138 image->arch.pgd, pmd, image->arch.pte1,
139 __pa(control_page), __pa(control_page));
140}
141
142/*
143 * A architecture hook called to validate the
144 * proposed image and prepare the control pages
145 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
146 * have been allocated, but the segments have yet
147 * been copied into the kernel.
148 *
149 * Do what every setup is needed on image and the
150 * reboot code buffer to allow us to avoid allocations
151 * later.
152 *
153 * - Make control page executable.
154 * - Allocate page tables
155 * - Setup page tables
156 */
157int machine_kexec_prepare(struct kimage *image)
158{
159 int error;
160
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 */
173void machine_kexec_cleanup(struct kimage *image)
174{
175 set_pages_nx(image->control_code_page, 1);
176 machine_kexec_free_page_tables(image);
177}
178
179/*
180 * Do not allocate memory (or fail in any way) in machine_kexec().
181 * We are past the point of no return, committed to rebooting now.
182 */
183void machine_kexec(struct kimage *image)
184{
185 unsigned long page_list[PAGES_NR];
186 void *control_page;
187 int save_ftrace_enabled;
188 asmlinkage unsigned long
189 (*relocate_kernel_ptr)(unsigned long indirection_page,
190 unsigned long control_page,
191 unsigned long start_address,
192 unsigned int has_pae,
193 unsigned int preserve_context);
194
195#ifdef CONFIG_KEXEC_JUMP
196 if (image->preserve_context)
197 save_processor_state();
198#endif
199
200 save_ftrace_enabled = __ftrace_enabled_save();
201
202 /* Interrupts aren't acceptable while we reboot */
203 local_irq_disable();
204 hw_breakpoint_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
263void 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