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 16 #include <asm/pgtable.h> 17 #include <asm/tlbflush.h> 18 #include <asm/mmu_context.h> 19 #include <asm/io.h> 20 21 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) 22 static u64 kexec_pgd[512] PAGE_ALIGNED; 23 static u64 kexec_pud0[512] PAGE_ALIGNED; 24 static u64 kexec_pmd0[512] PAGE_ALIGNED; 25 static u64 kexec_pte0[512] PAGE_ALIGNED; 26 static u64 kexec_pud1[512] PAGE_ALIGNED; 27 static u64 kexec_pmd1[512] PAGE_ALIGNED; 28 static u64 kexec_pte1[512] PAGE_ALIGNED; 29 30 static void init_level2_page(pmd_t *level2p, unsigned long addr) 31 { 32 unsigned long end_addr; 33 34 addr &= PAGE_MASK; 35 end_addr = addr + PUD_SIZE; 36 while (addr < end_addr) { 37 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC)); 38 addr += PMD_SIZE; 39 } 40 } 41 42 static int init_level3_page(struct kimage *image, pud_t *level3p, 43 unsigned long addr, unsigned long last_addr) 44 { 45 unsigned long end_addr; 46 int result; 47 48 result = 0; 49 addr &= PAGE_MASK; 50 end_addr = addr + PGDIR_SIZE; 51 while ((addr < last_addr) && (addr < end_addr)) { 52 struct page *page; 53 pmd_t *level2p; 54 55 page = kimage_alloc_control_pages(image, 0); 56 if (!page) { 57 result = -ENOMEM; 58 goto out; 59 } 60 level2p = (pmd_t *)page_address(page); 61 init_level2_page(level2p, addr); 62 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE)); 63 addr += PUD_SIZE; 64 } 65 /* clear the unused entries */ 66 while (addr < end_addr) { 67 pud_clear(level3p++); 68 addr += PUD_SIZE; 69 } 70 out: 71 return result; 72 } 73 74 75 static int init_level4_page(struct kimage *image, pgd_t *level4p, 76 unsigned long addr, unsigned long last_addr) 77 { 78 unsigned long end_addr; 79 int result; 80 81 result = 0; 82 addr &= PAGE_MASK; 83 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE); 84 while ((addr < last_addr) && (addr < end_addr)) { 85 struct page *page; 86 pud_t *level3p; 87 88 page = kimage_alloc_control_pages(image, 0); 89 if (!page) { 90 result = -ENOMEM; 91 goto out; 92 } 93 level3p = (pud_t *)page_address(page); 94 result = init_level3_page(image, level3p, addr, last_addr); 95 if (result) { 96 goto out; 97 } 98 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE)); 99 addr += PGDIR_SIZE; 100 } 101 /* clear the unused entries */ 102 while (addr < end_addr) { 103 pgd_clear(level4p++); 104 addr += PGDIR_SIZE; 105 } 106 out: 107 return result; 108 } 109 110 111 static int init_pgtable(struct kimage *image, unsigned long start_pgtable) 112 { 113 pgd_t *level4p; 114 level4p = (pgd_t *)__va(start_pgtable); 115 return init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT); 116 } 117 118 static void set_idt(void *newidt, u16 limit) 119 { 120 struct desc_ptr curidt; 121 122 /* x86-64 supports unaliged loads & stores */ 123 curidt.size = limit; 124 curidt.address = (unsigned long)newidt; 125 126 __asm__ __volatile__ ( 127 "lidtq %0\n" 128 : : "m" (curidt) 129 ); 130 }; 131 132 133 static void set_gdt(void *newgdt, u16 limit) 134 { 135 struct desc_ptr curgdt; 136 137 /* x86-64 supports unaligned loads & stores */ 138 curgdt.size = limit; 139 curgdt.address = (unsigned long)newgdt; 140 141 __asm__ __volatile__ ( 142 "lgdtq %0\n" 143 : : "m" (curgdt) 144 ); 145 }; 146 147 static void load_segments(void) 148 { 149 __asm__ __volatile__ ( 150 "\tmovl %0,%%ds\n" 151 "\tmovl %0,%%es\n" 152 "\tmovl %0,%%ss\n" 153 "\tmovl %0,%%fs\n" 154 "\tmovl %0,%%gs\n" 155 : : "a" (__KERNEL_DS) : "memory" 156 ); 157 } 158 159 int machine_kexec_prepare(struct kimage *image) 160 { 161 unsigned long start_pgtable; 162 int result; 163 164 /* Calculate the offsets */ 165 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; 166 167 /* Setup the identity mapped 64bit page table */ 168 result = init_pgtable(image, start_pgtable); 169 if (result) 170 return result; 171 172 return 0; 173 } 174 175 void machine_kexec_cleanup(struct kimage *image) 176 { 177 return; 178 } 179 180 /* 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. 183 */ 184 NORET_TYPE void machine_kexec(struct kimage *image) 185 { 186 unsigned long page_list[PAGES_NR]; 187 void *control_page; 188 189 tracer_disable(); 190 191 /* Interrupts aren't acceptable while we reboot */ 192 local_irq_disable(); 193 194 control_page = page_address(image->control_code_page) + PAGE_SIZE; 195 memcpy(control_page, relocate_kernel, PAGE_SIZE); 196 197 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); 198 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; 199 page_list[PA_PGD] = virt_to_phys(&kexec_pgd); 200 page_list[VA_PGD] = (unsigned long)kexec_pgd; 201 page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0); 202 page_list[VA_PUD_0] = (unsigned long)kexec_pud0; 203 page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0); 204 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; 205 page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0); 206 page_list[VA_PTE_0] = (unsigned long)kexec_pte0; 207 page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1); 208 page_list[VA_PUD_1] = (unsigned long)kexec_pud1; 209 page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1); 210 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; 211 page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1); 212 page_list[VA_PTE_1] = (unsigned long)kexec_pte1; 213 214 page_list[PA_TABLE_PAGE] = 215 (unsigned long)__pa(page_address(image->control_code_page)); 216 217 /* The segment registers are funny things, they have both a 218 * visible and an invisible part. Whenever the visible part is 219 * set to a specific selector, the invisible part is loaded 220 * with from a table in memory. At no other time is the 221 * descriptor table in memory accessed. 222 * 223 * I take advantage of this here by force loading the 224 * segments, before I zap the gdt with an invalid value. 225 */ 226 load_segments(); 227 /* The gdt & idt are now invalid. 228 * If you want to load them you must set up your own idt & gdt. 229 */ 230 set_gdt(phys_to_virt(0),0); 231 set_idt(phys_to_virt(0),0); 232 233 /* now call it */ 234 relocate_kernel((unsigned long)image->head, (unsigned long)page_list, 235 image->start); 236 } 237 238 void arch_crash_save_vmcoreinfo(void) 239 { 240 VMCOREINFO_SYMBOL(phys_base); 241 VMCOREINFO_SYMBOL(init_level4_pgt); 242 243 #ifdef CONFIG_NUMA 244 VMCOREINFO_SYMBOL(node_data); 245 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); 246 #endif 247 } 248 249