machine_kexec_32.c 6.9 KB

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