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/delay.h>
12 #include <linux/numa.h>
13 #include <linux/ftrace.h>
14 #include <linux/suspend.h>
15 #include <linux/gfp.h>
18 #include <asm/pgtable.h>
19 #include <asm/pgalloc.h>
20 #include <asm/tlbflush.h>
21 #include <asm/mmu_context.h>
23 #include <asm/io_apic.h>
24 #include <asm/cpufeature.h>
26 #include <asm/set_memory.h>
27 #include <asm/debugreg.h>
29 static void set_gdt(void *newgdt
, __u16 limit
)
31 struct desc_ptr curgdt
;
33 /* ia32 supports unaligned loads & stores */
35 curgdt
.address
= (unsigned long)newgdt
;
40 static void load_segments(void)
43 #define STR(X) __STR(X)
45 __asm__
__volatile__ (
46 "\tljmp $"STR(__KERNEL_CS
)",$1f\n"
48 "\tmovl $"STR(__KERNEL_DS
)",%%eax\n"
54 : : : "eax", "memory");
59 static void machine_kexec_free_page_tables(struct kimage
*image
)
61 free_page((unsigned long)image
->arch
.pgd
);
63 free_page((unsigned long)image
->arch
.pmd0
);
64 free_page((unsigned long)image
->arch
.pmd1
);
66 free_page((unsigned long)image
->arch
.pte0
);
67 free_page((unsigned long)image
->arch
.pte1
);
70 static int machine_kexec_alloc_page_tables(struct kimage
*image
)
72 image
->arch
.pgd
= (pgd_t
*)get_zeroed_page(GFP_KERNEL
);
74 image
->arch
.pmd0
= (pmd_t
*)get_zeroed_page(GFP_KERNEL
);
75 image
->arch
.pmd1
= (pmd_t
*)get_zeroed_page(GFP_KERNEL
);
77 image
->arch
.pte0
= (pte_t
*)get_zeroed_page(GFP_KERNEL
);
78 image
->arch
.pte1
= (pte_t
*)get_zeroed_page(GFP_KERNEL
);
79 if (!image
->arch
.pgd
||
81 !image
->arch
.pmd0
|| !image
->arch
.pmd1
||
83 !image
->arch
.pte0
|| !image
->arch
.pte1
) {
84 machine_kexec_free_page_tables(image
);
90 static void machine_kexec_page_table_set_one(
91 pgd_t
*pgd
, pmd_t
*pmd
, pte_t
*pte
,
92 unsigned long vaddr
, unsigned long paddr
)
97 pgd
+= pgd_index(vaddr
);
99 if (!(pgd_val(*pgd
) & _PAGE_PRESENT
))
100 set_pgd(pgd
, __pgd(__pa(pmd
) | _PAGE_PRESENT
));
102 p4d
= p4d_offset(pgd
, vaddr
);
103 pud
= pud_offset(p4d
, vaddr
);
104 pmd
= pmd_offset(pud
, vaddr
);
105 if (!(pmd_val(*pmd
) & _PAGE_PRESENT
))
106 set_pmd(pmd
, __pmd(__pa(pte
) | _PAGE_TABLE
));
107 pte
= pte_offset_kernel(pmd
, vaddr
);
108 set_pte(pte
, pfn_pte(paddr
>> PAGE_SHIFT
, PAGE_KERNEL_EXEC
));
111 static void machine_kexec_prepare_page_tables(struct kimage
*image
)
116 control_page
= page_address(image
->control_code_page
);
117 #ifdef CONFIG_X86_PAE
118 pmd
= image
->arch
.pmd0
;
120 machine_kexec_page_table_set_one(
121 image
->arch
.pgd
, pmd
, image
->arch
.pte0
,
122 (unsigned long)control_page
, __pa(control_page
));
123 #ifdef CONFIG_X86_PAE
124 pmd
= image
->arch
.pmd1
;
126 machine_kexec_page_table_set_one(
127 image
->arch
.pgd
, pmd
, image
->arch
.pte1
,
128 __pa(control_page
), __pa(control_page
));
132 * A architecture hook called to validate the
133 * proposed image and prepare the control pages
134 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
135 * have been allocated, but the segments have yet
136 * been copied into the kernel.
138 * Do what every setup is needed on image and the
139 * reboot code buffer to allow us to avoid allocations
142 * - Make control page executable.
143 * - Allocate page tables
144 * - Setup page tables
146 int machine_kexec_prepare(struct kimage
*image
)
150 set_pages_x(image
->control_code_page
, 1);
151 error
= machine_kexec_alloc_page_tables(image
);
154 machine_kexec_prepare_page_tables(image
);
159 * Undo anything leftover by machine_kexec_prepare
160 * when an image is freed.
162 void machine_kexec_cleanup(struct kimage
*image
)
164 set_pages_nx(image
->control_code_page
, 1);
165 machine_kexec_free_page_tables(image
);
169 * Do not allocate memory (or fail in any way) in machine_kexec().
170 * We are past the point of no return, committed to rebooting now.
172 void machine_kexec(struct kimage
*image
)
174 unsigned long page_list
[PAGES_NR
];
176 int save_ftrace_enabled
;
177 asmlinkage
unsigned long
178 (*relocate_kernel_ptr
)(unsigned long indirection_page
,
179 unsigned long control_page
,
180 unsigned long start_address
,
181 unsigned int has_pae
,
182 unsigned int preserve_context
);
184 #ifdef CONFIG_KEXEC_JUMP
185 if (image
->preserve_context
)
186 save_processor_state();
189 save_ftrace_enabled
= __ftrace_enabled_save();
191 /* Interrupts aren't acceptable while we reboot */
193 hw_breakpoint_disable();
195 if (image
->preserve_context
) {
196 #ifdef CONFIG_X86_IO_APIC
198 * We need to put APICs in legacy mode so that we can
199 * get timer interrupts in second kernel. kexec/kdump
200 * paths already have calls to disable_IO_APIC() in
201 * one form or other. kexec jump path also need
208 control_page
= page_address(image
->control_code_page
);
209 memcpy(control_page
, relocate_kernel
, KEXEC_CONTROL_CODE_MAX_SIZE
);
211 relocate_kernel_ptr
= control_page
;
212 page_list
[PA_CONTROL_PAGE
] = __pa(control_page
);
213 page_list
[VA_CONTROL_PAGE
] = (unsigned long)control_page
;
214 page_list
[PA_PGD
] = __pa(image
->arch
.pgd
);
216 if (image
->type
== KEXEC_TYPE_DEFAULT
)
217 page_list
[PA_SWAP_PAGE
] = (page_to_pfn(image
->swap_page
)
221 * The segment registers are funny things, they have both a
222 * visible and an invisible part. Whenever the visible part is
223 * set to a specific selector, the invisible part is loaded
224 * with from a table in memory. At no other time is the
225 * descriptor table in memory accessed.
227 * I take advantage of this here by force loading the
228 * segments, before I zap the gdt with an invalid value.
232 * The gdt & idt are now invalid.
233 * If you want to load them you must set up your own idt & gdt.
235 set_gdt(phys_to_virt(0), 0);
236 idt_invalidate(phys_to_virt(0));
239 image
->start
= relocate_kernel_ptr((unsigned long)image
->head
,
240 (unsigned long)page_list
,
242 boot_cpu_has(X86_FEATURE_PAE
),
243 image
->preserve_context
);
245 #ifdef CONFIG_KEXEC_JUMP
246 if (image
->preserve_context
)
247 restore_processor_state();
250 __ftrace_enabled_restore(save_ftrace_enabled
);
253 void arch_crash_save_vmcoreinfo(void)
256 VMCOREINFO_SYMBOL(node_data
);
257 VMCOREINFO_LENGTH(node_data
, MAX_NUMNODES
);
259 #ifdef CONFIG_X86_PAE
260 VMCOREINFO_CONFIG(X86_PAE
);