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 <asm/pgtable.h> 15 #include <asm/tlbflush.h> 16 #include <asm/mmu_context.h> 17 #include <asm/io.h> 18 19 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) 20 static u64 kexec_pgd[512] PAGE_ALIGNED; 21 static u64 kexec_pud0[512] PAGE_ALIGNED; 22 static u64 kexec_pmd0[512] PAGE_ALIGNED; 23 static u64 kexec_pte0[512] PAGE_ALIGNED; 24 static u64 kexec_pud1[512] PAGE_ALIGNED; 25 static u64 kexec_pmd1[512] PAGE_ALIGNED; 26 static u64 kexec_pte1[512] PAGE_ALIGNED; 27 28 static void init_level2_page(pmd_t *level2p, unsigned long addr) 29 { 30 unsigned long end_addr; 31 32 addr &= PAGE_MASK; 33 end_addr = addr + PUD_SIZE; 34 while (addr < end_addr) { 35 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC)); 36 addr += PMD_SIZE; 37 } 38 } 39 40 static int init_level3_page(struct kimage *image, pud_t *level3p, 41 unsigned long addr, unsigned long last_addr) 42 { 43 unsigned long end_addr; 44 int result; 45 46 result = 0; 47 addr &= PAGE_MASK; 48 end_addr = addr + PGDIR_SIZE; 49 while ((addr < last_addr) && (addr < end_addr)) { 50 struct page *page; 51 pmd_t *level2p; 52 53 page = kimage_alloc_control_pages(image, 0); 54 if (!page) { 55 result = -ENOMEM; 56 goto out; 57 } 58 level2p = (pmd_t *)page_address(page); 59 init_level2_page(level2p, addr); 60 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE)); 61 addr += PUD_SIZE; 62 } 63 /* clear the unused entries */ 64 while (addr < end_addr) { 65 pud_clear(level3p++); 66 addr += PUD_SIZE; 67 } 68 out: 69 return result; 70 } 71 72 73 static int init_level4_page(struct kimage *image, pgd_t *level4p, 74 unsigned long addr, unsigned long last_addr) 75 { 76 unsigned long end_addr; 77 int result; 78 79 result = 0; 80 addr &= PAGE_MASK; 81 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE); 82 while ((addr < last_addr) && (addr < end_addr)) { 83 struct page *page; 84 pud_t *level3p; 85 86 page = kimage_alloc_control_pages(image, 0); 87 if (!page) { 88 result = -ENOMEM; 89 goto out; 90 } 91 level3p = (pud_t *)page_address(page); 92 result = init_level3_page(image, level3p, addr, last_addr); 93 if (result) { 94 goto out; 95 } 96 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE)); 97 addr += PGDIR_SIZE; 98 } 99 /* clear the unused entries */ 100 while (addr < end_addr) { 101 pgd_clear(level4p++); 102 addr += PGDIR_SIZE; 103 } 104 out: 105 return result; 106 } 107 108 109 static int init_pgtable(struct kimage *image, unsigned long start_pgtable) 110 { 111 pgd_t *level4p; 112 level4p = (pgd_t *)__va(start_pgtable); 113 return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT); 114 } 115 116 static void set_idt(void *newidt, u16 limit) 117 { 118 struct desc_ptr curidt; 119 120 /* x86-64 supports unaliged loads & stores */ 121 curidt.size = limit; 122 curidt.address = (unsigned long)newidt; 123 124 __asm__ __volatile__ ( 125 "lidtq %0\n" 126 : : "m" (curidt) 127 ); 128 }; 129 130 131 static void set_gdt(void *newgdt, u16 limit) 132 { 133 struct desc_ptr curgdt; 134 135 /* x86-64 supports unaligned loads & stores */ 136 curgdt.size = limit; 137 curgdt.address = (unsigned long)newgdt; 138 139 __asm__ __volatile__ ( 140 "lgdtq %0\n" 141 : : "m" (curgdt) 142 ); 143 }; 144 145 static void load_segments(void) 146 { 147 __asm__ __volatile__ ( 148 "\tmovl %0,%%ds\n" 149 "\tmovl %0,%%es\n" 150 "\tmovl %0,%%ss\n" 151 "\tmovl %0,%%fs\n" 152 "\tmovl %0,%%gs\n" 153 : : "a" (__KERNEL_DS) : "memory" 154 ); 155 } 156 157 int machine_kexec_prepare(struct kimage *image) 158 { 159 unsigned long start_pgtable; 160 int result; 161 162 /* Calculate the offsets */ 163 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; 164 165 /* Setup the identity mapped 64bit page table */ 166 result = init_pgtable(image, start_pgtable); 167 if (result) 168 return result; 169 170 return 0; 171 } 172 173 void machine_kexec_cleanup(struct kimage *image) 174 { 175 return; 176 } 177 178 /* 179 * Do not allocate memory (or fail in any way) in machine_kexec(). 180 * We are past the point of no return, committed to rebooting now. 181 */ 182 NORET_TYPE void machine_kexec(struct kimage *image) 183 { 184 unsigned long page_list[PAGES_NR]; 185 void *control_page; 186 187 /* Interrupts aren't acceptable while we reboot */ 188 local_irq_disable(); 189 190 control_page = page_address(image->control_code_page) + PAGE_SIZE; 191 memcpy(control_page, relocate_kernel, PAGE_SIZE); 192 193 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); 194 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; 195 page_list[PA_PGD] = virt_to_phys(&kexec_pgd); 196 page_list[VA_PGD] = (unsigned long)kexec_pgd; 197 page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0); 198 page_list[VA_PUD_0] = (unsigned long)kexec_pud0; 199 page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0); 200 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; 201 page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0); 202 page_list[VA_PTE_0] = (unsigned long)kexec_pte0; 203 page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1); 204 page_list[VA_PUD_1] = (unsigned long)kexec_pud1; 205 page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1); 206 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; 207 page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1); 208 page_list[VA_PTE_1] = (unsigned long)kexec_pte1; 209 210 page_list[PA_TABLE_PAGE] = 211 (unsigned long)__pa(page_address(image->control_code_page)); 212 213 /* The segment registers are funny things, they have both a 214 * visible and an invisible part. Whenever the visible part is 215 * set to a specific selector, the invisible part is loaded 216 * with from a table in memory. At no other time is the 217 * descriptor table in memory accessed. 218 * 219 * I take advantage of this here by force loading the 220 * segments, before I zap the gdt with an invalid value. 221 */ 222 load_segments(); 223 /* The gdt & idt are now invalid. 224 * If you want to load them you must set up your own idt & gdt. 225 */ 226 set_gdt(phys_to_virt(0),0); 227 set_idt(phys_to_virt(0),0); 228 229 /* now call it */ 230 relocate_kernel((unsigned long)image->head, (unsigned long)page_list, 231 image->start); 232 } 233 234 void arch_crash_save_vmcoreinfo(void) 235 { 236 VMCOREINFO_SYMBOL(phys_base); 237 VMCOREINFO_SYMBOL(init_level4_pgt); 238 239 #ifdef CONFIG_NUMA 240 VMCOREINFO_SYMBOL(node_data); 241 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); 242 #endif 243 } 244 245