1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
|
/*
* handle transition of Linux booting another kernel
* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/numa.h>
#include <linux/ftrace.h>
#include <linux/suspend.h>
#include <linux/gfp.h>
#include <linux/io.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/apic.h>
#include <asm/cpufeature.h>
#include <asm/desc.h>
#include <asm/system.h>
#include <asm/cacheflush.h>
#include <asm/debugreg.h>
static void set_idt(void *newidt, __u16 limit)
{
struct desc_ptr curidt;
/* ia32 supports unaliged loads & stores */
curidt.size = limit;
curidt.address = (unsigned long)newidt;
load_idt(&curidt);
}
static void set_gdt(void *newgdt, __u16 limit)
{
struct desc_ptr curgdt;
/* ia32 supports unaligned loads & stores */
curgdt.size = limit;
curgdt.address = (unsigned long)newgdt;
load_gdt(&curgdt);
}
static void load_segments(void)
{
#define __STR(X) #X
#define STR(X) __STR(X)
__asm__ __volatile__ (
"\tljmp $"STR(__KERNEL_CS)",$1f\n"
"\t1:\n"
"\tmovl $"STR(__KERNEL_DS)",%%eax\n"
"\tmovl %%eax,%%ds\n"
"\tmovl %%eax,%%es\n"
"\tmovl %%eax,%%fs\n"
"\tmovl %%eax,%%gs\n"
"\tmovl %%eax,%%ss\n"
: : : "eax", "memory");
#undef STR
#undef __STR
}
static void machine_kexec_free_page_tables(struct kimage *image)
{
free_page((unsigned long)image->arch.pgd);
#ifdef CONFIG_X86_PAE
free_page((unsigned long)image->arch.pmd0);
free_page((unsigned long)image->arch.pmd1);
#endif
free_page((unsigned long)image->arch.pte0);
free_page((unsigned long)image->arch.pte1);
}
static int machine_kexec_alloc_page_tables(struct kimage *image)
{
image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
#ifdef CONFIG_X86_PAE
image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
#endif
image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
if (!image->arch.pgd ||
#ifdef CONFIG_X86_PAE
!image->arch.pmd0 || !image->arch.pmd1 ||
#endif
!image->arch.pte0 || !image->arch.pte1) {
machine_kexec_free_page_tables(image);
return -ENOMEM;
}
return 0;
}
static void machine_kexec_page_table_set_one(
pgd_t *pgd, pmd_t *pmd, pte_t *pte,
unsigned long vaddr, unsigned long paddr)
{
pud_t *pud;
pgd += pgd_index(vaddr);
#ifdef CONFIG_X86_PAE
if (!(pgd_val(*pgd) & _PAGE_PRESENT))
set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
#endif
pud = pud_offset(pgd, vaddr);
pmd = pmd_offset(pud, vaddr);
if (!(pmd_val(*pmd) & _PAGE_PRESENT))
set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
pte = pte_offset_kernel(pmd, vaddr);
set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
}
static void machine_kexec_prepare_page_tables(struct kimage *image)
{
void *control_page;
pmd_t *pmd = NULL;
control_page = page_address(image->control_code_page);
#ifdef CONFIG_X86_PAE
pmd = image->arch.pmd0;
#endif
machine_kexec_page_table_set_one(
image->arch.pgd, pmd, image->arch.pte0,
(unsigned long)control_page, __pa(control_page));
#ifdef CONFIG_X86_PAE
pmd = image->arch.pmd1;
#endif
machine_kexec_page_table_set_one(
image->arch.pgd, pmd, image->arch.pte1,
__pa(control_page), __pa(control_page));
}
/*
* A architecture hook called to validate the
* proposed image and prepare the control pages
* as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
* have been allocated, but the segments have yet
* been copied into the kernel.
*
* Do what every setup is needed on image and the
* reboot code buffer to allow us to avoid allocations
* later.
*
* - Make control page executable.
* - Allocate page tables
* - Setup page tables
*/
int machine_kexec_prepare(struct kimage *image)
{
int error;
if (nx_enabled)
set_pages_x(image->control_code_page, 1);
error = machine_kexec_alloc_page_tables(image);
if (error)
return error;
machine_kexec_prepare_page_tables(image);
return 0;
}
/*
* Undo anything leftover by machine_kexec_prepare
* when an image is freed.
*/
void machine_kexec_cleanup(struct kimage *image)
{
if (nx_enabled)
set_pages_nx(image->control_code_page, 1);
machine_kexec_free_page_tables(image);
}
/*
* Do not allocate memory (or fail in any way) in machine_kexec().
* We are past the point of no return, committed to rebooting now.
*/
void machine_kexec(struct kimage *image)
{
unsigned long page_list[PAGES_NR];
void *control_page;
int save_ftrace_enabled;
asmlinkage unsigned long
(*relocate_kernel_ptr)(unsigned long indirection_page,
unsigned long control_page,
unsigned long start_address,
unsigned int has_pae,
unsigned int preserve_context);
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
save_processor_state();
#endif
save_ftrace_enabled = __ftrace_enabled_save();
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
hw_breakpoint_disable();
if (image->preserve_context) {
#ifdef CONFIG_X86_IO_APIC
/*
* We need to put APICs in legacy mode so that we can
* get timer interrupts in second kernel. kexec/kdump
* paths already have calls to disable_IO_APIC() in
* one form or other. kexec jump path also need
* one.
*/
disable_IO_APIC();
#endif
}
control_page = page_address(image->control_code_page);
memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
relocate_kernel_ptr = control_page;
page_list[PA_CONTROL_PAGE] = __pa(control_page);
page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
page_list[PA_PGD] = __pa(image->arch.pgd);
if (image->type == KEXEC_TYPE_DEFAULT)
page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
<< PAGE_SHIFT);
/*
* The segment registers are funny things, they have both a
* visible and an invisible part. Whenever the visible part is
* set to a specific selector, the invisible part is loaded
* with from a table in memory. At no other time is the
* descriptor table in memory accessed.
*
* I take advantage of this here by force loading the
* segments, before I zap the gdt with an invalid value.
*/
load_segments();
/*
* The gdt & idt are now invalid.
* If you want to load them you must set up your own idt & gdt.
*/
set_gdt(phys_to_virt(0), 0);
set_idt(phys_to_virt(0), 0);
/* now call it */
image->start = relocate_kernel_ptr((unsigned long)image->head,
(unsigned long)page_list,
image->start, cpu_has_pae,
image->preserve_context);
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
restore_processor_state();
#endif
__ftrace_enabled_restore(save_ftrace_enabled);
}
void arch_crash_save_vmcoreinfo(void)
{
#ifdef CONFIG_NUMA
VMCOREINFO_SYMBOL(node_data);
VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
#ifdef CONFIG_X86_PAE
VMCOREINFO_CONFIG(X86_PAE);
#endif
}
|
