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_idt(void *newidt, __u16 limit)
31 struct desc_ptr curidt;
33 /* ia32 supports unaliged loads & stores */
35 curidt.address = (unsigned long)newidt;
41 static void set_gdt(void *newgdt, __u16 limit)
43 struct desc_ptr curgdt;
45 /* ia32 supports unaligned loads & stores */
47 curgdt.address = (unsigned long)newgdt;
52 static void load_segments(void)
55 #define STR(X) __STR(X)
57 __asm__ __volatile__ (
58 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
60 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
66 : : : "eax", "memory");
71 static void machine_kexec_free_page_tables(struct kimage *image)
73 free_page((unsigned long)image->arch.pgd);
75 free_page((unsigned long)image->arch.pmd0);
76 free_page((unsigned long)image->arch.pmd1);
78 free_page((unsigned long)image->arch.pte0);
79 free_page((unsigned long)image->arch.pte1);
82 static int machine_kexec_alloc_page_tables(struct kimage *image)
84 image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
86 image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
87 image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
89 image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
90 image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
91 if (!image->arch.pgd ||
93 !image->arch.pmd0 || !image->arch.pmd1 ||
95 !image->arch.pte0 || !image->arch.pte1) {
96 machine_kexec_free_page_tables(image);
102 static void machine_kexec_page_table_set_one(
103 pgd_t *pgd, pmd_t *pmd, pte_t *pte,
104 unsigned long vaddr, unsigned long paddr)
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));
114 p4d = p4d_offset(pgd, vaddr);
115 pud = pud_offset(p4d, vaddr);
116 pmd = pmd_offset(pud, vaddr);
117 if (!(pmd_val(*pmd) & _PAGE_PRESENT))
118 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
119 pte = pte_offset_kernel(pmd, vaddr);
120 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
123 static void machine_kexec_prepare_page_tables(struct kimage *image)
128 control_page = page_address(image->control_code_page);
129 #ifdef CONFIG_X86_PAE
130 pmd = image->arch.pmd0;
132 machine_kexec_page_table_set_one(
133 image->arch.pgd, pmd, image->arch.pte0,
134 (unsigned long)control_page, __pa(control_page));
135 #ifdef CONFIG_X86_PAE
136 pmd = image->arch.pmd1;
138 machine_kexec_page_table_set_one(
139 image->arch.pgd, pmd, image->arch.pte1,
140 __pa(control_page), __pa(control_page));
144 * A architecture hook called to validate the
145 * proposed image and prepare the control pages
146 * as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
147 * have been allocated, but the segments have yet
148 * been copied into the kernel.
150 * Do what every setup is needed on image and the
151 * reboot code buffer to allow us to avoid allocations
154 * - Make control page executable.
155 * - Allocate page tables
156 * - Setup page tables
158 int machine_kexec_prepare(struct kimage *image)
162 set_pages_x(image->control_code_page, 1);
163 error = machine_kexec_alloc_page_tables(image);
166 machine_kexec_prepare_page_tables(image);
171 * Undo anything leftover by machine_kexec_prepare
172 * when an image is freed.
174 void machine_kexec_cleanup(struct kimage *image)
176 set_pages_nx(image->control_code_page, 1);
177 machine_kexec_free_page_tables(image);
181 * Do not allocate memory (or fail in any way) in machine_kexec().
182 * We are past the point of no return, committed to rebooting now.
184 void machine_kexec(struct kimage *image)
186 unsigned long page_list[PAGES_NR];
188 int save_ftrace_enabled;
189 asmlinkage unsigned long
190 (*relocate_kernel_ptr)(unsigned long indirection_page,
191 unsigned long control_page,
192 unsigned long start_address,
193 unsigned int has_pae,
194 unsigned int preserve_context);
196 #ifdef CONFIG_KEXEC_JUMP
197 if (image->preserve_context)
198 save_processor_state();
201 save_ftrace_enabled = __ftrace_enabled_save();
203 /* Interrupts aren't acceptable while we reboot */
205 hw_breakpoint_disable();
207 if (image->preserve_context) {
208 #ifdef CONFIG_X86_IO_APIC
210 * We need to put APICs in legacy mode so that we can
211 * get timer interrupts in second kernel. kexec/kdump
212 * paths already have calls to disable_IO_APIC() in
213 * one form or other. kexec jump path also need
220 control_page = page_address(image->control_code_page);
221 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
223 relocate_kernel_ptr = control_page;
224 page_list[PA_CONTROL_PAGE] = __pa(control_page);
225 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
226 page_list[PA_PGD] = __pa(image->arch.pgd);
228 if (image->type == KEXEC_TYPE_DEFAULT)
229 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
233 * The segment registers are funny things, they have both a
234 * visible and an invisible part. Whenever the visible part is
235 * set to a specific selector, the invisible part is loaded
236 * with from a table in memory. At no other time is the
237 * descriptor table in memory accessed.
239 * I take advantage of this here by force loading the
240 * segments, before I zap the gdt with an invalid value.
244 * The gdt & idt are now invalid.
245 * If you want to load them you must set up your own idt & gdt.
247 set_gdt(phys_to_virt(0), 0);
248 set_idt(phys_to_virt(0), 0);
251 image->start = relocate_kernel_ptr((unsigned long)image->head,
252 (unsigned long)page_list,
254 boot_cpu_has(X86_FEATURE_PAE),
255 image->preserve_context);
257 #ifdef CONFIG_KEXEC_JUMP
258 if (image->preserve_context)
259 restore_processor_state();
262 __ftrace_enabled_restore(save_ftrace_enabled);
265 void arch_crash_save_vmcoreinfo(void)
268 VMCOREINFO_SYMBOL(node_data);
269 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
271 #ifdef CONFIG_X86_PAE
272 VMCOREINFO_CONFIG(X86_PAE);