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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/io_apic.h>
 24 #include <asm/cpufeature.h>
 25 #include <asm/desc.h>
 26 #include <asm/set_memory.h>
 27 #include <asm/debugreg.h>
 28 
 29 static void set_gdt(void *newgdt, __u16 limit)
 30 {
 31         struct desc_ptr curgdt;
 32 
 33         /* ia32 supports unaligned loads & stores */
 34         curgdt.size    = limit;
 35         curgdt.address = (unsigned long)newgdt;
 36 
 37         load_gdt(&curgdt);
 38 }
 39 
 40 static void load_segments(void)
 41 {
 42 #define __STR(X) #X
 43 #define STR(X) __STR(X)
 44 
 45         __asm__ __volatile__ (
 46                 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
 47                 "\t1:\n"
 48                 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
 49                 "\tmovl %%eax,%%ds\n"
 50                 "\tmovl %%eax,%%es\n"
 51                 "\tmovl %%eax,%%ss\n"
 52                 : : : "eax", "memory");
 53 #undef STR
 54 #undef __STR
 55 }
 56 
 57 static void machine_kexec_free_page_tables(struct kimage *image)
 58 {
 59         free_page((unsigned long)image->arch.pgd);
 60         image->arch.pgd = NULL;
 61 #ifdef CONFIG_X86_PAE
 62         free_page((unsigned long)image->arch.pmd0);
 63         image->arch.pmd0 = NULL;
 64         free_page((unsigned long)image->arch.pmd1);
 65         image->arch.pmd1 = NULL;
 66 #endif
 67         free_page((unsigned long)image->arch.pte0);
 68         image->arch.pte0 = NULL;
 69         free_page((unsigned long)image->arch.pte1);
 70         image->arch.pte1 = NULL;
 71 }
 72 
 73 static int machine_kexec_alloc_page_tables(struct kimage *image)
 74 {
 75         image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
 76 #ifdef CONFIG_X86_PAE
 77         image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 78         image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 79 #endif
 80         image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
 81         image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
 82         if (!image->arch.pgd ||
 83 #ifdef CONFIG_X86_PAE
 84             !image->arch.pmd0 || !image->arch.pmd1 ||
 85 #endif
 86             !image->arch.pte0 || !image->arch.pte1) {
 87                 return -ENOMEM;
 88         }
 89         return 0;
 90 }
 91 
 92 static void machine_kexec_page_table_set_one(
 93         pgd_t *pgd, pmd_t *pmd, pte_t *pte,
 94         unsigned long vaddr, unsigned long paddr)
 95 {
 96         p4d_t *p4d;
 97         pud_t *pud;
 98 
 99         pgd += pgd_index(vaddr);
100 #ifdef CONFIG_X86_PAE
101         if (!(pgd_val(*pgd) & _PAGE_PRESENT))
102                 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
103 #endif
104         p4d = p4d_offset(pgd, vaddr);
105         pud = pud_offset(p4d, vaddr);
106         pmd = pmd_offset(pud, vaddr);
107         if (!(pmd_val(*pmd) & _PAGE_PRESENT))
108                 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
109         pte = pte_offset_kernel(pmd, vaddr);
110         set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
111 }
112 
113 static void machine_kexec_prepare_page_tables(struct kimage *image)
114 {
115         void *control_page;
116         pmd_t *pmd = NULL;
117 
118         control_page = page_address(image->control_code_page);
119 #ifdef CONFIG_X86_PAE
120         pmd = image->arch.pmd0;
121 #endif
122         machine_kexec_page_table_set_one(
123                 image->arch.pgd, pmd, image->arch.pte0,
124                 (unsigned long)control_page, __pa(control_page));
125 #ifdef CONFIG_X86_PAE
126         pmd = image->arch.pmd1;
127 #endif
128         machine_kexec_page_table_set_one(
129                 image->arch.pgd, pmd, image->arch.pte1,
130                 __pa(control_page), __pa(control_page));
131 }
132 
133 /*
134  * A architecture hook called to validate the
135  * proposed image and prepare the control pages
136  * as needed.  The pages for KEXEC_CONTROL_PAGE_SIZE
137  * have been allocated, but the segments have yet
138  * been copied into the kernel.
139  *
140  * Do what every setup is needed on image and the
141  * reboot code buffer to allow us to avoid allocations
142  * later.
143  *
144  * - Make control page executable.
145  * - Allocate page tables
146  * - Setup page tables
147  */
148 int machine_kexec_prepare(struct kimage *image)
149 {
150         int error;
151 
152         set_pages_x(image->control_code_page, 1);
153         error = machine_kexec_alloc_page_tables(image);
154         if (error)
155                 return error;
156         machine_kexec_prepare_page_tables(image);
157         return 0;
158 }
159 
160 /*
161  * Undo anything leftover by machine_kexec_prepare
162  * when an image is freed.
163  */
164 void machine_kexec_cleanup(struct kimage *image)
165 {
166         set_pages_nx(image->control_code_page, 1);
167         machine_kexec_free_page_tables(image);
168 }
169 
170 /*
171  * Do not allocate memory (or fail in any way) in machine_kexec().
172  * We are past the point of no return, committed to rebooting now.
173  */
174 void machine_kexec(struct kimage *image)
175 {
176         unsigned long page_list[PAGES_NR];
177         void *control_page;
178         int save_ftrace_enabled;
179         asmlinkage unsigned long
180                 (*relocate_kernel_ptr)(unsigned long indirection_page,
181                                        unsigned long control_page,
182                                        unsigned long start_address,
183                                        unsigned int has_pae,
184                                        unsigned int preserve_context);
185 
186 #ifdef CONFIG_KEXEC_JUMP
187         if (image->preserve_context)
188                 save_processor_state();
189 #endif
190 
191         save_ftrace_enabled = __ftrace_enabled_save();
192 
193         /* Interrupts aren't acceptable while we reboot */
194         local_irq_disable();
195         hw_breakpoint_disable();
196 
197         if (image->preserve_context) {
198 #ifdef CONFIG_X86_IO_APIC
199                 /*
200                  * We need to put APICs in legacy mode so that we can
201                  * get timer interrupts in second kernel. kexec/kdump
202                  * paths already have calls to disable_IO_APIC() in
203                  * one form or other. kexec jump path also need
204                  * one.
205                  */
206                 disable_IO_APIC();
207 #endif
208         }
209 
210         control_page = page_address(image->control_code_page);
211         memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
212 
213         relocate_kernel_ptr = control_page;
214         page_list[PA_CONTROL_PAGE] = __pa(control_page);
215         page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
216         page_list[PA_PGD] = __pa(image->arch.pgd);
217 
218         if (image->type == KEXEC_TYPE_DEFAULT)
219                 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
220                                                 << PAGE_SHIFT);
221 
222         /*
223          * The segment registers are funny things, they have both a
224          * visible and an invisible part.  Whenever the visible part is
225          * set to a specific selector, the invisible part is loaded
226          * with from a table in memory.  At no other time is the
227          * descriptor table in memory accessed.
228          *
229          * I take advantage of this here by force loading the
230          * segments, before I zap the gdt with an invalid value.
231          */
232         load_segments();
233         /*
234          * The gdt & idt are now invalid.
235          * If you want to load them you must set up your own idt & gdt.
236          */
237         idt_invalidate(phys_to_virt(0));
238         set_gdt(phys_to_virt(0), 0);
239 
240         /* now call it */
241         image->start = relocate_kernel_ptr((unsigned long)image->head,
242                                            (unsigned long)page_list,
243                                            image->start,
244                                            boot_cpu_has(X86_FEATURE_PAE),
245                                            image->preserve_context);
246 
247 #ifdef CONFIG_KEXEC_JUMP
248         if (image->preserve_context)
249                 restore_processor_state();
250 #endif
251 
252         __ftrace_enabled_restore(save_ftrace_enabled);
253 }
254 
255 void arch_crash_save_vmcoreinfo(void)
256 {
257 #ifdef CONFIG_NUMA
258         VMCOREINFO_SYMBOL(node_data);
259         VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
260 #endif
261 #ifdef CONFIG_X86_PAE
262         VMCOREINFO_CONFIG(X86_PAE);
263 #endif
264 }
265 
266 

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