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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/x86/kernel/machine_kexec_64.c
2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
10 #include <linux/kexec.h>
11 #include <linux/string.h>
12 #include <linux/reboot.h>
13 #include <asm/pgtable.h>
14 #include <asm/tlbflush.h>
15 #include <asm/mmu_context.h>
18 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
19 static u64 kexec_pgd
[512] PAGE_ALIGNED
;
20 static u64 kexec_pud0
[512] PAGE_ALIGNED
;
21 static u64 kexec_pmd0
[512] PAGE_ALIGNED
;
22 static u64 kexec_pte0
[512] PAGE_ALIGNED
;
23 static u64 kexec_pud1
[512] PAGE_ALIGNED
;
24 static u64 kexec_pmd1
[512] PAGE_ALIGNED
;
25 static u64 kexec_pte1
[512] PAGE_ALIGNED
;
27 static void init_level2_page(pmd_t
*level2p
, unsigned long addr
)
29 unsigned long end_addr
;
32 end_addr
= addr
+ PUD_SIZE
;
33 while (addr
< end_addr
) {
34 set_pmd(level2p
++, __pmd(addr
| __PAGE_KERNEL_LARGE_EXEC
));
39 static int init_level3_page(struct kimage
*image
, pud_t
*level3p
,
40 unsigned long addr
, unsigned long last_addr
)
42 unsigned long end_addr
;
47 end_addr
= addr
+ PGDIR_SIZE
;
48 while ((addr
< last_addr
) && (addr
< end_addr
)) {
52 page
= kimage_alloc_control_pages(image
, 0);
57 level2p
= (pmd_t
*)page_address(page
);
58 init_level2_page(level2p
, addr
);
59 set_pud(level3p
++, __pud(__pa(level2p
) | _KERNPG_TABLE
));
62 /* clear the unused entries */
63 while (addr
< end_addr
) {
72 static int init_level4_page(struct kimage
*image
, pgd_t
*level4p
,
73 unsigned long addr
, unsigned long last_addr
)
75 unsigned long end_addr
;
80 end_addr
= addr
+ (PTRS_PER_PGD
* PGDIR_SIZE
);
81 while ((addr
< last_addr
) && (addr
< end_addr
)) {
85 page
= kimage_alloc_control_pages(image
, 0);
90 level3p
= (pud_t
*)page_address(page
);
91 result
= init_level3_page(image
, level3p
, addr
, last_addr
);
95 set_pgd(level4p
++, __pgd(__pa(level3p
) | _KERNPG_TABLE
));
98 /* clear the unused entries */
99 while (addr
< end_addr
) {
100 pgd_clear(level4p
++);
108 static int init_pgtable(struct kimage
*image
, unsigned long start_pgtable
)
111 level4p
= (pgd_t
*)__va(start_pgtable
);
112 return init_level4_page(image
, level4p
, 0, end_pfn
<< PAGE_SHIFT
);
115 static void set_idt(void *newidt
, u16 limit
)
117 struct desc_ptr curidt
;
119 /* x86-64 supports unaliged loads & stores */
121 curidt
.address
= (unsigned long)newidt
;
123 __asm__
__volatile__ (
130 static void set_gdt(void *newgdt
, u16 limit
)
132 struct desc_ptr curgdt
;
134 /* x86-64 supports unaligned loads & stores */
136 curgdt
.address
= (unsigned long)newgdt
;
138 __asm__
__volatile__ (
144 static void load_segments(void)
146 __asm__
__volatile__ (
152 : : "a" (__KERNEL_DS
) : "memory"
156 int machine_kexec_prepare(struct kimage
*image
)
158 unsigned long start_pgtable
;
161 /* Calculate the offsets */
162 start_pgtable
= page_to_pfn(image
->control_code_page
) << PAGE_SHIFT
;
164 /* Setup the identity mapped 64bit page table */
165 result
= init_pgtable(image
, start_pgtable
);
172 void machine_kexec_cleanup(struct kimage
*image
)
178 * Do not allocate memory (or fail in any way) in machine_kexec().
179 * We are past the point of no return, committed to rebooting now.
181 NORET_TYPE
void machine_kexec(struct kimage
*image
)
183 unsigned long page_list
[PAGES_NR
];
186 /* Interrupts aren't acceptable while we reboot */
189 control_page
= page_address(image
->control_code_page
) + PAGE_SIZE
;
190 memcpy(control_page
, relocate_kernel
, PAGE_SIZE
);
192 page_list
[PA_CONTROL_PAGE
] = virt_to_phys(control_page
);
193 page_list
[VA_CONTROL_PAGE
] = (unsigned long)relocate_kernel
;
194 page_list
[PA_PGD
] = virt_to_phys(&kexec_pgd
);
195 page_list
[VA_PGD
] = (unsigned long)kexec_pgd
;
196 page_list
[PA_PUD_0
] = virt_to_phys(&kexec_pud0
);
197 page_list
[VA_PUD_0
] = (unsigned long)kexec_pud0
;
198 page_list
[PA_PMD_0
] = virt_to_phys(&kexec_pmd0
);
199 page_list
[VA_PMD_0
] = (unsigned long)kexec_pmd0
;
200 page_list
[PA_PTE_0
] = virt_to_phys(&kexec_pte0
);
201 page_list
[VA_PTE_0
] = (unsigned long)kexec_pte0
;
202 page_list
[PA_PUD_1
] = virt_to_phys(&kexec_pud1
);
203 page_list
[VA_PUD_1
] = (unsigned long)kexec_pud1
;
204 page_list
[PA_PMD_1
] = virt_to_phys(&kexec_pmd1
);
205 page_list
[VA_PMD_1
] = (unsigned long)kexec_pmd1
;
206 page_list
[PA_PTE_1
] = virt_to_phys(&kexec_pte1
);
207 page_list
[VA_PTE_1
] = (unsigned long)kexec_pte1
;
209 page_list
[PA_TABLE_PAGE
] =
210 (unsigned long)__pa(page_address(image
->control_code_page
));
212 /* The segment registers are funny things, they have both a
213 * visible and an invisible part. Whenever the visible part is
214 * set to a specific selector, the invisible part is loaded
215 * with from a table in memory. At no other time is the
216 * descriptor table in memory accessed.
218 * I take advantage of this here by force loading the
219 * segments, before I zap the gdt with an invalid value.
222 /* The gdt & idt are now invalid.
223 * If you want to load them you must set up your own idt & gdt.
225 set_gdt(phys_to_virt(0),0);
226 set_idt(phys_to_virt(0),0);
229 relocate_kernel((unsigned long)image
->head
, (unsigned long)page_list
,
233 /* crashkernel=size@addr specifies the location to reserve for
234 * a crash kernel. By reserving this memory we guarantee
235 * that linux never set's it up as a DMA target.
236 * Useful for holding code to do something appropriate
237 * after a kernel panic.
239 static int __init
setup_crashkernel(char *arg
)
241 unsigned long size
, base
;
245 size
= memparse(arg
, &p
);
249 base
= memparse(p
+1, &p
);
250 /* FIXME: Do I want a sanity check to validate the
251 * memory range? Yes you do, but it's too early for
253 crashk_res
.start
= base
;
254 crashk_res
.end
= base
+ size
- 1;
258 early_param("crashkernel", setup_crashkernel
);