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Linux/arch/x86/kernel/machine_kexec_32.c

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

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