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/string.h> 12 #include <linux/reboot.h> 13 #include <linux/numa.h> 14 #include <linux/ftrace.h> 15 #include <linux/io.h> 16 #include <linux/suspend.h> 17 18 #include <asm/pgtable.h> 19 #include <asm/tlbflush.h> 20 #include <asm/mmu_context.h> 21 #include <asm/debugreg.h> 22 23 static int init_one_level2_page(struct kimage *image, pgd_t *pgd, 24 unsigned long addr) 25 { 26 pud_t *pud; 27 pmd_t *pmd; 28 struct page *page; 29 int result = -ENOMEM; 30 31 addr &= PMD_MASK; 32 pgd += pgd_index(addr); 33 if (!pgd_present(*pgd)) { 34 page = kimage_alloc_control_pages(image, 0); 35 if (!page) 36 goto out; 37 pud = (pud_t *)page_address(page); 38 memset(pud, 0, PAGE_SIZE); 39 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE)); 40 } 41 pud = pud_offset(pgd, addr); 42 if (!pud_present(*pud)) { 43 page = kimage_alloc_control_pages(image, 0); 44 if (!page) 45 goto out; 46 pmd = (pmd_t *)page_address(page); 47 memset(pmd, 0, PAGE_SIZE); 48 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); 49 } 50 pmd = pmd_offset(pud, addr); 51 if (!pmd_present(*pmd)) 52 set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC)); 53 result = 0; 54 out: 55 return result; 56 } 57 58 static void init_level2_page(pmd_t *level2p, unsigned long addr) 59 { 60 unsigned long end_addr; 61 62 addr &= PAGE_MASK; 63 end_addr = addr + PUD_SIZE; 64 while (addr < end_addr) { 65 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC)); 66 addr += PMD_SIZE; 67 } 68 } 69 70 static int init_level3_page(struct kimage *image, pud_t *level3p, 71 unsigned long addr, unsigned long last_addr) 72 { 73 unsigned long end_addr; 74 int result; 75 76 result = 0; 77 addr &= PAGE_MASK; 78 end_addr = addr + PGDIR_SIZE; 79 while ((addr < last_addr) && (addr < end_addr)) { 80 struct page *page; 81 pmd_t *level2p; 82 83 page = kimage_alloc_control_pages(image, 0); 84 if (!page) { 85 result = -ENOMEM; 86 goto out; 87 } 88 level2p = (pmd_t *)page_address(page); 89 init_level2_page(level2p, addr); 90 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE)); 91 addr += PUD_SIZE; 92 } 93 /* clear the unused entries */ 94 while (addr < end_addr) { 95 pud_clear(level3p++); 96 addr += PUD_SIZE; 97 } 98 out: 99 return result; 100 } 101 102 103 static int init_level4_page(struct kimage *image, pgd_t *level4p, 104 unsigned long addr, unsigned long last_addr) 105 { 106 unsigned long end_addr; 107 int result; 108 109 result = 0; 110 addr &= PAGE_MASK; 111 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE); 112 while ((addr < last_addr) && (addr < end_addr)) { 113 struct page *page; 114 pud_t *level3p; 115 116 page = kimage_alloc_control_pages(image, 0); 117 if (!page) { 118 result = -ENOMEM; 119 goto out; 120 } 121 level3p = (pud_t *)page_address(page); 122 result = init_level3_page(image, level3p, addr, last_addr); 123 if (result) 124 goto out; 125 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE)); 126 addr += PGDIR_SIZE; 127 } 128 /* clear the unused entries */ 129 while (addr < end_addr) { 130 pgd_clear(level4p++); 131 addr += PGDIR_SIZE; 132 } 133 out: 134 return result; 135 } 136 137 static void free_transition_pgtable(struct kimage *image) 138 { 139 free_page((unsigned long)image->arch.pud); 140 free_page((unsigned long)image->arch.pmd); 141 free_page((unsigned long)image->arch.pte); 142 } 143 144 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) 145 { 146 pud_t *pud; 147 pmd_t *pmd; 148 pte_t *pte; 149 unsigned long vaddr, paddr; 150 int result = -ENOMEM; 151 152 vaddr = (unsigned long)relocate_kernel; 153 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE); 154 pgd += pgd_index(vaddr); 155 if (!pgd_present(*pgd)) { 156 pud = (pud_t *)get_zeroed_page(GFP_KERNEL); 157 if (!pud) 158 goto err; 159 image->arch.pud = pud; 160 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE)); 161 } 162 pud = pud_offset(pgd, vaddr); 163 if (!pud_present(*pud)) { 164 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL); 165 if (!pmd) 166 goto err; 167 image->arch.pmd = pmd; 168 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); 169 } 170 pmd = pmd_offset(pud, vaddr); 171 if (!pmd_present(*pmd)) { 172 pte = (pte_t *)get_zeroed_page(GFP_KERNEL); 173 if (!pte) 174 goto err; 175 image->arch.pte = pte; 176 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); 177 } 178 pte = pte_offset_kernel(pmd, vaddr); 179 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC)); 180 return 0; 181 err: 182 free_transition_pgtable(image); 183 return result; 184 } 185 186 187 static int init_pgtable(struct kimage *image, unsigned long start_pgtable) 188 { 189 pgd_t *level4p; 190 int result; 191 level4p = (pgd_t *)__va(start_pgtable); 192 result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT); 193 if (result) 194 return result; 195 /* 196 * image->start may be outside 0 ~ max_pfn, for example when 197 * jump back to original kernel from kexeced kernel 198 */ 199 result = init_one_level2_page(image, level4p, image->start); 200 if (result) 201 return result; 202 return init_transition_pgtable(image, level4p); 203 } 204 205 static void set_idt(void *newidt, u16 limit) 206 { 207 struct desc_ptr curidt; 208 209 /* x86-64 supports unaliged loads & stores */ 210 curidt.size = limit; 211 curidt.address = (unsigned long)newidt; 212 213 __asm__ __volatile__ ( 214 "lidtq %0\n" 215 : : "m" (curidt) 216 ); 217 }; 218 219 220 static void set_gdt(void *newgdt, u16 limit) 221 { 222 struct desc_ptr curgdt; 223 224 /* x86-64 supports unaligned loads & stores */ 225 curgdt.size = limit; 226 curgdt.address = (unsigned long)newgdt; 227 228 __asm__ __volatile__ ( 229 "lgdtq %0\n" 230 : : "m" (curgdt) 231 ); 232 }; 233 234 static void load_segments(void) 235 { 236 __asm__ __volatile__ ( 237 "\tmovl %0,%%ds\n" 238 "\tmovl %0,%%es\n" 239 "\tmovl %0,%%ss\n" 240 "\tmovl %0,%%fs\n" 241 "\tmovl %0,%%gs\n" 242 : : "a" (__KERNEL_DS) : "memory" 243 ); 244 } 245 246 int machine_kexec_prepare(struct kimage *image) 247 { 248 unsigned long start_pgtable; 249 int result; 250 251 /* Calculate the offsets */ 252 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; 253 254 /* Setup the identity mapped 64bit page table */ 255 result = init_pgtable(image, start_pgtable); 256 if (result) 257 return result; 258 259 return 0; 260 } 261 262 void machine_kexec_cleanup(struct kimage *image) 263 { 264 free_transition_pgtable(image); 265 } 266 267 /* 268 * Do not allocate memory (or fail in any way) in machine_kexec(). 269 * We are past the point of no return, committed to rebooting now. 270 */ 271 void machine_kexec(struct kimage *image) 272 { 273 unsigned long page_list[PAGES_NR]; 274 void *control_page; 275 int save_ftrace_enabled; 276 277 #ifdef CONFIG_KEXEC_JUMP 278 if (image->preserve_context) 279 save_processor_state(); 280 #endif 281 282 save_ftrace_enabled = __ftrace_enabled_save(); 283 284 /* Interrupts aren't acceptable while we reboot */ 285 local_irq_disable(); 286 hw_breakpoint_disable(); 287 288 if (image->preserve_context) { 289 #ifdef CONFIG_X86_IO_APIC 290 /* 291 * We need to put APICs in legacy mode so that we can 292 * get timer interrupts in second kernel. kexec/kdump 293 * paths already have calls to disable_IO_APIC() in 294 * one form or other. kexec jump path also need 295 * one. 296 */ 297 disable_IO_APIC(); 298 #endif 299 } 300 301 control_page = page_address(image->control_code_page) + PAGE_SIZE; 302 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE); 303 304 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); 305 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page; 306 page_list[PA_TABLE_PAGE] = 307 (unsigned long)__pa(page_address(image->control_code_page)); 308 309 if (image->type == KEXEC_TYPE_DEFAULT) 310 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page) 311 << PAGE_SHIFT); 312 313 /* 314 * The segment registers are funny things, they have both a 315 * visible and an invisible part. Whenever the visible part is 316 * set to a specific selector, the invisible part is loaded 317 * with from a table in memory. At no other time is the 318 * descriptor table in memory accessed. 319 * 320 * I take advantage of this here by force loading the 321 * segments, before I zap the gdt with an invalid value. 322 */ 323 load_segments(); 324 /* 325 * The gdt & idt are now invalid. 326 * If you want to load them you must set up your own idt & gdt. 327 */ 328 set_gdt(phys_to_virt(0), 0); 329 set_idt(phys_to_virt(0), 0); 330 331 /* now call it */ 332 image->start = relocate_kernel((unsigned long)image->head, 333 (unsigned long)page_list, 334 image->start, 335 image->preserve_context); 336 337 #ifdef CONFIG_KEXEC_JUMP 338 if (image->preserve_context) 339 restore_processor_state(); 340 #endif 341 342 __ftrace_enabled_restore(save_ftrace_enabled); 343 } 344 345 void arch_crash_save_vmcoreinfo(void) 346 { 347 VMCOREINFO_SYMBOL(phys_base); 348 VMCOREINFO_SYMBOL(init_level4_pgt); 349 350 #ifdef CONFIG_NUMA 351 VMCOREINFO_SYMBOL(node_data); 352 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); 353 #endif 354 } 355 356