Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 1 | /* |
| 2 | * machine_kexec.c - 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/string.h> |
| 13 | #include <linux/reboot.h> |
| 14 | #include <asm/pda.h> |
| 15 | #include <asm/pgtable.h> |
| 16 | #include <asm/pgalloc.h> |
| 17 | #include <asm/tlbflush.h> |
| 18 | #include <asm/mmu_context.h> |
| 19 | #include <asm/io.h> |
| 20 | #include <asm/apic.h> |
| 21 | #include <asm/cpufeature.h> |
| 22 | #include <asm/hw_irq.h> |
| 23 | |
| 24 | #define LEVEL0_SIZE (1UL << 12UL) |
| 25 | #define LEVEL1_SIZE (1UL << 21UL) |
| 26 | #define LEVEL2_SIZE (1UL << 30UL) |
| 27 | #define LEVEL3_SIZE (1UL << 39UL) |
| 28 | #define LEVEL4_SIZE (1UL << 48UL) |
| 29 | |
| 30 | #define L0_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) |
| 31 | #define L1_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE) |
| 32 | #define L2_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) |
| 33 | #define L3_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) |
| 34 | |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 35 | static void init_level2_page(u64 *level2p, unsigned long addr) |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 36 | { |
| 37 | unsigned long end_addr; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 38 | |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 39 | addr &= PAGE_MASK; |
| 40 | end_addr = addr + LEVEL2_SIZE; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 41 | while (addr < end_addr) { |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 42 | *(level2p++) = addr | L1_ATTR; |
| 43 | addr += LEVEL1_SIZE; |
| 44 | } |
| 45 | } |
| 46 | |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 47 | static int init_level3_page(struct kimage *image, u64 *level3p, |
| 48 | unsigned long addr, unsigned long last_addr) |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 49 | { |
| 50 | unsigned long end_addr; |
| 51 | int result; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 52 | |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 53 | result = 0; |
| 54 | addr &= PAGE_MASK; |
| 55 | end_addr = addr + LEVEL3_SIZE; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 56 | while ((addr < last_addr) && (addr < end_addr)) { |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 57 | struct page *page; |
| 58 | u64 *level2p; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 59 | |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 60 | page = kimage_alloc_control_pages(image, 0); |
| 61 | if (!page) { |
| 62 | result = -ENOMEM; |
| 63 | goto out; |
| 64 | } |
| 65 | level2p = (u64 *)page_address(page); |
| 66 | init_level2_page(level2p, addr); |
| 67 | *(level3p++) = __pa(level2p) | L2_ATTR; |
| 68 | addr += LEVEL2_SIZE; |
| 69 | } |
| 70 | /* clear the unused entries */ |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 71 | while (addr < end_addr) { |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 72 | *(level3p++) = 0; |
| 73 | addr += LEVEL2_SIZE; |
| 74 | } |
| 75 | out: |
| 76 | return result; |
| 77 | } |
| 78 | |
| 79 | |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 80 | static int init_level4_page(struct kimage *image, u64 *level4p, |
| 81 | unsigned long addr, unsigned long last_addr) |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 82 | { |
| 83 | unsigned long end_addr; |
| 84 | int result; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 85 | |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 86 | result = 0; |
| 87 | addr &= PAGE_MASK; |
| 88 | end_addr = addr + LEVEL4_SIZE; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 89 | while ((addr < last_addr) && (addr < end_addr)) { |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 90 | struct page *page; |
| 91 | u64 *level3p; |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 92 | |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 93 | page = kimage_alloc_control_pages(image, 0); |
| 94 | if (!page) { |
| 95 | result = -ENOMEM; |
| 96 | goto out; |
| 97 | } |
| 98 | level3p = (u64 *)page_address(page); |
| 99 | result = init_level3_page(image, level3p, addr, last_addr); |
| 100 | if (result) { |
| 101 | goto out; |
| 102 | } |
| 103 | *(level4p++) = __pa(level3p) | L3_ATTR; |
| 104 | addr += LEVEL3_SIZE; |
| 105 | } |
| 106 | /* clear the unused entries */ |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 107 | while (addr < end_addr) { |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 108 | *(level4p++) = 0; |
| 109 | addr += LEVEL3_SIZE; |
| 110 | } |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 111 | out: |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 112 | return result; |
| 113 | } |
| 114 | |
| 115 | |
| 116 | static int init_pgtable(struct kimage *image, unsigned long start_pgtable) |
| 117 | { |
| 118 | u64 *level4p; |
| 119 | level4p = (u64 *)__va(start_pgtable); |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 120 | return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT); |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 121 | } |
| 122 | |
| 123 | static void set_idt(void *newidt, u16 limit) |
| 124 | { |
| 125 | unsigned char curidt[10]; |
| 126 | |
| 127 | /* x86-64 supports unaliged loads & stores */ |
| 128 | (*(u16 *)(curidt)) = limit; |
| 129 | (*(u64 *)(curidt +2)) = (unsigned long)(newidt); |
| 130 | |
| 131 | __asm__ __volatile__ ( |
| 132 | "lidt %0\n" |
| 133 | : "=m" (curidt) |
| 134 | ); |
| 135 | }; |
| 136 | |
| 137 | |
| 138 | static void set_gdt(void *newgdt, u16 limit) |
| 139 | { |
| 140 | unsigned char curgdt[10]; |
| 141 | |
| 142 | /* x86-64 supports unaligned loads & stores */ |
| 143 | (*(u16 *)(curgdt)) = limit; |
| 144 | (*(u64 *)(curgdt +2)) = (unsigned long)(newgdt); |
| 145 | |
| 146 | __asm__ __volatile__ ( |
| 147 | "lgdt %0\n" |
| 148 | : "=m" (curgdt) |
| 149 | ); |
| 150 | }; |
| 151 | |
| 152 | static void load_segments(void) |
| 153 | { |
| 154 | __asm__ __volatile__ ( |
| 155 | "\tmovl $"STR(__KERNEL_DS)",%eax\n" |
| 156 | "\tmovl %eax,%ds\n" |
| 157 | "\tmovl %eax,%es\n" |
| 158 | "\tmovl %eax,%ss\n" |
| 159 | "\tmovl %eax,%fs\n" |
| 160 | "\tmovl %eax,%gs\n" |
| 161 | ); |
| 162 | #undef STR |
| 163 | #undef __STR |
| 164 | } |
| 165 | |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 166 | typedef NORET_TYPE void (*relocate_new_kernel_t)(unsigned long indirection_page, |
| 167 | unsigned long control_code_buffer, |
| 168 | unsigned long start_address, |
| 169 | unsigned long pgtable) ATTRIB_NORET; |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 170 | |
| 171 | const extern unsigned char relocate_new_kernel[]; |
| 172 | const extern unsigned long relocate_new_kernel_size; |
| 173 | |
| 174 | int machine_kexec_prepare(struct kimage *image) |
| 175 | { |
| 176 | unsigned long start_pgtable, control_code_buffer; |
| 177 | int result; |
| 178 | |
| 179 | /* Calculate the offsets */ |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 180 | start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 181 | control_code_buffer = start_pgtable + 4096UL; |
| 182 | |
| 183 | /* Setup the identity mapped 64bit page table */ |
| 184 | result = init_pgtable(image, start_pgtable); |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 185 | if (result) |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 186 | return result; |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 187 | |
| 188 | /* Place the code in the reboot code buffer */ |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 189 | memcpy(__va(control_code_buffer), relocate_new_kernel, |
| 190 | relocate_new_kernel_size); |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 191 | |
| 192 | return 0; |
| 193 | } |
| 194 | |
| 195 | void machine_kexec_cleanup(struct kimage *image) |
| 196 | { |
| 197 | return; |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Do not allocate memory (or fail in any way) in machine_kexec(). |
| 202 | * We are past the point of no return, committed to rebooting now. |
| 203 | */ |
| 204 | NORET_TYPE void machine_kexec(struct kimage *image) |
| 205 | { |
| 206 | unsigned long page_list; |
| 207 | unsigned long control_code_buffer; |
| 208 | unsigned long start_pgtable; |
| 209 | relocate_new_kernel_t rnk; |
| 210 | |
| 211 | /* Interrupts aren't acceptable while we reboot */ |
| 212 | local_irq_disable(); |
| 213 | |
| 214 | /* Calculate the offsets */ |
Maneesh Soni | 72414d3 | 2005-06-25 14:58:28 -0700 | [diff] [blame] | 215 | page_list = image->head; |
| 216 | start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; |
Eric W. Biederman | 5234f5e | 2005-06-25 14:58:02 -0700 | [diff] [blame] | 217 | control_code_buffer = start_pgtable + 4096UL; |
| 218 | |
| 219 | /* Set the low half of the page table to my identity mapped |
| 220 | * page table for kexec. Leave the high half pointing at the |
| 221 | * kernel pages. Don't bother to flush the global pages |
| 222 | * as that will happen when I fully switch to my identity mapped |
| 223 | * page table anyway. |
| 224 | */ |
| 225 | memcpy(__va(read_cr3()), __va(start_pgtable), PAGE_SIZE/2); |
| 226 | __flush_tlb(); |
| 227 | |
| 228 | |
| 229 | /* The segment registers are funny things, they are |
| 230 | * automatically loaded from a table, in memory wherever you |
| 231 | * set them to a specific selector, but this table is never |
| 232 | * accessed again unless you set the segment to a different selector. |
| 233 | * |
| 234 | * The more common model are caches where the behide |
| 235 | * the scenes work is done, but is also dropped at arbitrary |
| 236 | * times. |
| 237 | * |
| 238 | * I take advantage of this here by force loading the |
| 239 | * segments, before I zap the gdt with an invalid value. |
| 240 | */ |
| 241 | load_segments(); |
| 242 | /* The gdt & idt are now invalid. |
| 243 | * If you want to load them you must set up your own idt & gdt. |
| 244 | */ |
| 245 | set_gdt(phys_to_virt(0),0); |
| 246 | set_idt(phys_to_virt(0),0); |
| 247 | /* now call it */ |
| 248 | rnk = (relocate_new_kernel_t) control_code_buffer; |
| 249 | (*rnk)(page_list, control_code_buffer, image->start, start_pgtable); |
| 250 | } |