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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/pgtable.h>
17#include <asm/pgalloc.h>
18#include <asm/tlbflush.h>
19#include <asm/mmu_context.h>
20#include <asm/apic.h>
21#include <asm/io_apic.h>
22#include <asm/cpufeature.h>
23#include <asm/desc.h>
24#include <asm/set_memory.h>
25#include <asm/debugreg.h>
26
27static void set_gdt(void *newgdt, __u16 limit)
28{
29 struct desc_ptr curgdt;
30
31 /* ia32 supports unaligned loads & stores */
32 curgdt.size = limit;
33 curgdt.address = (unsigned long)newgdt;
34
35 load_gdt(&curgdt);
36}
37
38static void load_segments(void)
39{
40#define __STR(X) #X
41#define STR(X) __STR(X)
42
43 __asm__ __volatile__ (
44 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
45 "\t1:\n"
46 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
47 "\tmovl %%eax,%%ds\n"
48 "\tmovl %%eax,%%es\n"
49 "\tmovl %%eax,%%ss\n"
50 : : : "eax", "memory");
51#undef STR
52#undef __STR
53}
54
55static void machine_kexec_free_page_tables(struct kimage *image)
56{
57 free_pages((unsigned long)image->arch.pgd, PGD_ALLOCATION_ORDER);
58 image->arch.pgd = NULL;
59#ifdef CONFIG_X86_PAE
60 free_page((unsigned long)image->arch.pmd0);
61 image->arch.pmd0 = NULL;
62 free_page((unsigned long)image->arch.pmd1);
63 image->arch.pmd1 = NULL;
64#endif
65 free_page((unsigned long)image->arch.pte0);
66 image->arch.pte0 = NULL;
67 free_page((unsigned long)image->arch.pte1);
68 image->arch.pte1 = NULL;
69}
70
71static int machine_kexec_alloc_page_tables(struct kimage *image)
72{
73 image->arch.pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
74 PGD_ALLOCATION_ORDER);
75#ifdef CONFIG_X86_PAE
76 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
77 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
78#endif
79 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
80 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
81 if (!image->arch.pgd ||
82#ifdef CONFIG_X86_PAE
83 !image->arch.pmd0 || !image->arch.pmd1 ||
84#endif
85 !image->arch.pte0 || !image->arch.pte1) {
86 return -ENOMEM;
87 }
88 return 0;
89}
90
91static void machine_kexec_page_table_set_one(
92 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
93 unsigned long vaddr, unsigned long paddr)
94{
95 p4d_t *p4d;
96 pud_t *pud;
97
98 pgd += pgd_index(vaddr);
99#ifdef CONFIG_X86_PAE
100 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
101 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
102#endif
103 p4d = p4d_offset(pgd, vaddr);
104 pud = pud_offset(p4d, vaddr);
105 pmd = pmd_offset(pud, vaddr);
106 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
107 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
108 pte = pte_offset_kernel(pmd, vaddr);
109 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
110}
111
112static void machine_kexec_prepare_page_tables(struct kimage *image)
113{
114 void *control_page;
115 pmd_t *pmd = NULL;
116
117 control_page = page_address(image->control_code_page);
118#ifdef CONFIG_X86_PAE
119 pmd = image->arch.pmd0;
120#endif
121 machine_kexec_page_table_set_one(
122 image->arch.pgd, pmd, image->arch.pte0,
123 (unsigned long)control_page, __pa(control_page));
124#ifdef CONFIG_X86_PAE
125 pmd = image->arch.pmd1;
126#endif
127 machine_kexec_page_table_set_one(
128 image->arch.pgd, pmd, image->arch.pte1,
129 __pa(control_page), __pa(control_page));
130}
131
132/*
133 * A architecture hook called to validate the
134 * proposed image and prepare the control pages
135 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
136 * have been allocated, but the segments have yet
137 * been copied into the kernel.
138 *
139 * Do what every setup is needed on image and the
140 * reboot code buffer to allow us to avoid allocations
141 * later.
142 *
143 * - Make control page executable.
144 * - Allocate page tables
145 * - Setup page tables
146 */
147int machine_kexec_prepare(struct kimage *image)
148{
149 int error;
150
151 set_memory_x((unsigned long)page_address(image->control_code_page), 1);
152 error = machine_kexec_alloc_page_tables(image);
153 if (error)
154 return error;
155 machine_kexec_prepare_page_tables(image);
156 return 0;
157}
158
159/*
160 * Undo anything leftover by machine_kexec_prepare
161 * when an image is freed.
162 */
163void machine_kexec_cleanup(struct kimage *image)
164{
165 set_memory_nx((unsigned long)page_address(image->control_code_page), 1);
166 machine_kexec_free_page_tables(image);
167}
168
169/*
170 * Do not allocate memory (or fail in any way) in machine_kexec().
171 * We are past the point of no return, committed to rebooting now.
172 */
173void machine_kexec(struct kimage *image)
174{
175 unsigned long page_list[PAGES_NR];
176 void *control_page;
177 int save_ftrace_enabled;
178 asmlinkage unsigned long
179 (*relocate_kernel_ptr)(unsigned long indirection_page,
180 unsigned long control_page,
181 unsigned long start_address,
182 unsigned int has_pae,
183 unsigned int preserve_context);
184
185#ifdef CONFIG_KEXEC_JUMP
186 if (image->preserve_context)
187 save_processor_state();
188#endif
189
190 save_ftrace_enabled = __ftrace_enabled_save();
191
192 /* Interrupts aren't acceptable while we reboot */
193 local_irq_disable();
194 hw_breakpoint_disable();
195
196 if (image->preserve_context) {
197#ifdef CONFIG_X86_IO_APIC
198 /*
199 * We need to put APICs in legacy mode so that we can
200 * get timer interrupts in second kernel. kexec/kdump
201 * paths already have calls to restore_boot_irq_mode()
202 * in one form or other. kexec jump path also need one.
203 */
204 clear_IO_APIC();
205 restore_boot_irq_mode();
206#endif
207 }
208
209 control_page = page_address(image->control_code_page);
210 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
211
212 relocate_kernel_ptr = control_page;
213 page_list[PA_CONTROL_PAGE] = __pa(control_page);
214 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
215 page_list[PA_PGD] = __pa(image->arch.pgd);
216
217 if (image->type == KEXEC_TYPE_DEFAULT)
218 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
219 << PAGE_SHIFT);
220
221 /*
222 * The segment registers are funny things, they have both a
223 * visible and an invisible part. Whenever the visible part is
224 * set to a specific selector, the invisible part is loaded
225 * with from a table in memory. At no other time is the
226 * descriptor table in memory accessed.
227 *
228 * I take advantage of this here by force loading the
229 * segments, before I zap the gdt with an invalid value.
230 */
231 load_segments();
232 /*
233 * The gdt & idt are now invalid.
234 * If you want to load them you must set up your own idt & gdt.
235 */
236 idt_invalidate(phys_to_virt(0));
237 set_gdt(phys_to_virt(0), 0);
238
239 /* now call it */
240 image->start = relocate_kernel_ptr((unsigned long)image->head,
241 (unsigned long)page_list,
242 image->start,
243 boot_cpu_has(X86_FEATURE_PAE),
244 image->preserve_context);
245
246#ifdef CONFIG_KEXEC_JUMP
247 if (image->preserve_context)
248 restore_processor_state();
249#endif
250
251 __ftrace_enabled_restore(save_ftrace_enabled);
252}
253
254void arch_crash_save_vmcoreinfo(void)
255{
256#ifdef CONFIG_NUMA
257 VMCOREINFO_SYMBOL(node_data);
258 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
259#endif
260#ifdef CONFIG_X86_PAE
261 VMCOREINFO_CONFIG(X86_PAE);
262#endif
263}
264
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/numa.h>
13#include <linux/ftrace.h>
14#include <linux/suspend.h>
15#include <linux/gfp.h>
16#include <linux/io.h>
17
18#include <asm/pgtable.h>
19#include <asm/pgalloc.h>
20#include <asm/tlbflush.h>
21#include <asm/mmu_context.h>
22#include <asm/apic.h>
23#include <asm/io_apic.h>
24#include <asm/cpufeature.h>
25#include <asm/desc.h>
26#include <asm/set_memory.h>
27#include <asm/debugreg.h>
28
29static void set_gdt(void *newgdt, __u16 limit)
30{
31 struct desc_ptr curgdt;
32
33 /* ia32 supports unaligned loads & stores */
34 curgdt.size = limit;
35 curgdt.address = (unsigned long)newgdt;
36
37 load_gdt(&curgdt);
38}
39
40static void load_segments(void)
41{
42#define __STR(X) #X
43#define STR(X) __STR(X)
44
45 __asm__ __volatile__ (
46 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
47 "\t1:\n"
48 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
49 "\tmovl %%eax,%%ds\n"
50 "\tmovl %%eax,%%es\n"
51 "\tmovl %%eax,%%ss\n"
52 : : : "eax", "memory");
53#undef STR
54#undef __STR
55}
56
57static void machine_kexec_free_page_tables(struct kimage *image)
58{
59 free_page((unsigned long)image->arch.pgd);
60 image->arch.pgd = NULL;
61#ifdef CONFIG_X86_PAE
62 free_page((unsigned long)image->arch.pmd0);
63 image->arch.pmd0 = NULL;
64 free_page((unsigned long)image->arch.pmd1);
65 image->arch.pmd1 = NULL;
66#endif
67 free_page((unsigned long)image->arch.pte0);
68 image->arch.pte0 = NULL;
69 free_page((unsigned long)image->arch.pte1);
70 image->arch.pte1 = NULL;
71}
72
73static int machine_kexec_alloc_page_tables(struct kimage *image)
74{
75 image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
76#ifdef CONFIG_X86_PAE
77 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
78 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
79#endif
80 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
81 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
82 if (!image->arch.pgd ||
83#ifdef CONFIG_X86_PAE
84 !image->arch.pmd0 || !image->arch.pmd1 ||
85#endif
86 !image->arch.pte0 || !image->arch.pte1) {
87 return -ENOMEM;
88 }
89 return 0;
90}
91
92static void machine_kexec_page_table_set_one(
93 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
94 unsigned long vaddr, unsigned long paddr)
95{
96 p4d_t *p4d;
97 pud_t *pud;
98
99 pgd += pgd_index(vaddr);
100#ifdef CONFIG_X86_PAE
101 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
102 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
103#endif
104 p4d = p4d_offset(pgd, vaddr);
105 pud = pud_offset(p4d, vaddr);
106 pmd = pmd_offset(pud, vaddr);
107 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
108 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
109 pte = pte_offset_kernel(pmd, vaddr);
110 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
111}
112
113static void machine_kexec_prepare_page_tables(struct kimage *image)
114{
115 void *control_page;
116 pmd_t *pmd = NULL;
117
118 control_page = page_address(image->control_code_page);
119#ifdef CONFIG_X86_PAE
120 pmd = image->arch.pmd0;
121#endif
122 machine_kexec_page_table_set_one(
123 image->arch.pgd, pmd, image->arch.pte0,
124 (unsigned long)control_page, __pa(control_page));
125#ifdef CONFIG_X86_PAE
126 pmd = image->arch.pmd1;
127#endif
128 machine_kexec_page_table_set_one(
129 image->arch.pgd, pmd, image->arch.pte1,
130 __pa(control_page), __pa(control_page));
131}
132
133/*
134 * A architecture hook called to validate the
135 * proposed image and prepare the control pages
136 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
137 * have been allocated, but the segments have yet
138 * been copied into the kernel.
139 *
140 * Do what every setup is needed on image and the
141 * reboot code buffer to allow us to avoid allocations
142 * later.
143 *
144 * - Make control page executable.
145 * - Allocate page tables
146 * - Setup page tables
147 */
148int machine_kexec_prepare(struct kimage *image)
149{
150 int error;
151
152 set_pages_x(image->control_code_page, 1);
153 error = machine_kexec_alloc_page_tables(image);
154 if (error)
155 return error;
156 machine_kexec_prepare_page_tables(image);
157 return 0;
158}
159
160/*
161 * Undo anything leftover by machine_kexec_prepare
162 * when an image is freed.
163 */
164void machine_kexec_cleanup(struct kimage *image)
165{
166 set_pages_nx(image->control_code_page, 1);
167 machine_kexec_free_page_tables(image);
168}
169
170/*
171 * Do not allocate memory (or fail in any way) in machine_kexec().
172 * We are past the point of no return, committed to rebooting now.
173 */
174void machine_kexec(struct kimage *image)
175{
176 unsigned long page_list[PAGES_NR];
177 void *control_page;
178 int save_ftrace_enabled;
179 asmlinkage unsigned long
180 (*relocate_kernel_ptr)(unsigned long indirection_page,
181 unsigned long control_page,
182 unsigned long start_address,
183 unsigned int has_pae,
184 unsigned int preserve_context);
185
186#ifdef CONFIG_KEXEC_JUMP
187 if (image->preserve_context)
188 save_processor_state();
189#endif
190
191 save_ftrace_enabled = __ftrace_enabled_save();
192
193 /* Interrupts aren't acceptable while we reboot */
194 local_irq_disable();
195 hw_breakpoint_disable();
196
197 if (image->preserve_context) {
198#ifdef CONFIG_X86_IO_APIC
199 /*
200 * We need to put APICs in legacy mode so that we can
201 * get timer interrupts in second kernel. kexec/kdump
202 * paths already have calls to restore_boot_irq_mode()
203 * in one form or other. kexec jump path also need one.
204 */
205 clear_IO_APIC();
206 restore_boot_irq_mode();
207#endif
208 }
209
210 control_page = page_address(image->control_code_page);
211 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
212
213 relocate_kernel_ptr = control_page;
214 page_list[PA_CONTROL_PAGE] = __pa(control_page);
215 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
216 page_list[PA_PGD] = __pa(image->arch.pgd);
217
218 if (image->type == KEXEC_TYPE_DEFAULT)
219 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
220 << PAGE_SHIFT);
221
222 /*
223 * The segment registers are funny things, they have both a
224 * visible and an invisible part. Whenever the visible part is
225 * set to a specific selector, the invisible part is loaded
226 * with from a table in memory. At no other time is the
227 * descriptor table in memory accessed.
228 *
229 * I take advantage of this here by force loading the
230 * segments, before I zap the gdt with an invalid value.
231 */
232 load_segments();
233 /*
234 * The gdt & idt are now invalid.
235 * If you want to load them you must set up your own idt & gdt.
236 */
237 idt_invalidate(phys_to_virt(0));
238 set_gdt(phys_to_virt(0), 0);
239
240 /* now call it */
241 image->start = relocate_kernel_ptr((unsigned long)image->head,
242 (unsigned long)page_list,
243 image->start,
244 boot_cpu_has(X86_FEATURE_PAE),
245 image->preserve_context);
246
247#ifdef CONFIG_KEXEC_JUMP
248 if (image->preserve_context)
249 restore_processor_state();
250#endif
251
252 __ftrace_enabled_restore(save_ftrace_enabled);
253}
254
255void arch_crash_save_vmcoreinfo(void)
256{
257#ifdef CONFIG_NUMA
258 VMCOREINFO_SYMBOL(node_data);
259 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
260#endif
261#ifdef CONFIG_X86_PAE
262 VMCOREINFO_CONFIG(X86_PAE);
263#endif
264}
265