1/* 2 * ld script for the x86 kernel 3 * 4 * Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz> 5 * 6 * Modernisation, unification and other changes and fixes: 7 * Copyright (C) 2007-2009 Sam Ravnborg <sam@ravnborg.org> 8 * 9 * 10 * Don't define absolute symbols until and unless you know that symbol 11 * value is should remain constant even if kernel image is relocated 12 * at run time. Absolute symbols are not relocated. If symbol value should 13 * change if kernel is relocated, make the symbol section relative and 14 * put it inside the section definition. 15 */ 16 17#ifdef CONFIG_X86_32 18#define LOAD_OFFSET __PAGE_OFFSET 19#else 20#define LOAD_OFFSET __START_KERNEL_map 21#endif 22 23#include <asm-generic/vmlinux.lds.h> 24#include <asm/asm-offsets.h> 25#include <asm/thread_info.h> 26#include <asm/page_types.h> 27#include <asm/cache.h> 28#include <asm/boot.h> 29 30#undef i386 /* in case the preprocessor is a 32bit one */ 31 32OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT) 33 34#ifdef CONFIG_X86_32 35OUTPUT_ARCH(i386) 36ENTRY(phys_startup_32) 37jiffies = jiffies_64; 38#else 39OUTPUT_ARCH(i386:x86-64) 40ENTRY(phys_startup_64) 41jiffies_64 = jiffies; 42#endif 43 44#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) 45/* 46 * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA 47 * we retain large page mappings for boundaries spanning kernel text, rodata 48 * and data sections. 49 * 50 * However, kernel identity mappings will have different RWX permissions 51 * to the pages mapping to text and to the pages padding (which are freed) the 52 * text section. Hence kernel identity mappings will be broken to smaller 53 * pages. For 64-bit, kernel text and kernel identity mappings are different, 54 * so we can enable protection checks that come with CONFIG_DEBUG_RODATA, 55 * as well as retain 2MB large page mappings for kernel text. 56 */ 57#define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); 58 59#define X64_ALIGN_DEBUG_RODATA_END \ 60 . = ALIGN(HPAGE_SIZE); \ 61 __end_rodata_hpage_align = .; 62 63#else 64 65#define X64_ALIGN_DEBUG_RODATA_BEGIN 66#define X64_ALIGN_DEBUG_RODATA_END 67 68#endif 69 70PHDRS { 71 text PT_LOAD FLAGS(5); /* R_E */ 72 data PT_LOAD FLAGS(7); /* RWE */ 73#ifdef CONFIG_X86_64 74 user PT_LOAD FLAGS(5); /* R_E */ 75#ifdef CONFIG_SMP 76 percpu PT_LOAD FLAGS(6); /* RW_ */ 77#endif 78 init PT_LOAD FLAGS(7); /* RWE */ 79#endif 80 note PT_NOTE FLAGS(0); /* ___ */ 81} 82 83SECTIONS 84{ 85#ifdef CONFIG_X86_32 86 . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR; 87 phys_startup_32 = startup_32 - LOAD_OFFSET; 88#else 89 . = __START_KERNEL; 90 phys_startup_64 = startup_64 - LOAD_OFFSET; 91#endif 92 93 /* Text and read-only data */ 94 .text : AT(ADDR(.text) - LOAD_OFFSET) { 95 _text = .; 96 /* bootstrapping code */ 97 HEAD_TEXT 98#ifdef CONFIG_X86_32 99 . = ALIGN(PAGE_SIZE); 100 *(.text..page_aligned) 101#endif 102 . = ALIGN(8); 103 _stext = .; 104 TEXT_TEXT 105 SCHED_TEXT 106 LOCK_TEXT 107 KPROBES_TEXT 108 IRQENTRY_TEXT 109 *(.fixup) 110 *(.gnu.warning) 111 /* End of text section */ 112 _etext = .; 113 } :text = 0x9090 114 115 NOTES :text :note 116 117 EXCEPTION_TABLE(16) :text = 0x9090 118 119 X64_ALIGN_DEBUG_RODATA_BEGIN 120 RO_DATA(PAGE_SIZE) 121 X64_ALIGN_DEBUG_RODATA_END 122 123 /* Data */ 124 .data : AT(ADDR(.data) - LOAD_OFFSET) { 125 /* Start of data section */ 126 _sdata = .; 127 128 /* init_task */ 129 INIT_TASK_DATA(THREAD_SIZE) 130 131#ifdef CONFIG_X86_32 132 /* 32 bit has nosave before _edata */ 133 NOSAVE_DATA 134#endif 135 136 PAGE_ALIGNED_DATA(PAGE_SIZE) 137 138 CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) 139 140 DATA_DATA 141 CONSTRUCTORS 142 143 /* rarely changed data like cpu maps */ 144 READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES) 145 146 /* End of data section */ 147 _edata = .; 148 } :data 149 150#ifdef CONFIG_X86_64 151 152#define VSYSCALL_ADDR (-10*1024*1024) 153 154#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET) 155#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET) 156 157#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0) 158#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET) 159 160 . = ALIGN(4096); 161 __vsyscall_0 = .; 162 163 . = VSYSCALL_ADDR; 164 .vsyscall_0 : AT(VLOAD(.vsyscall_0)) { 165 *(.vsyscall_0) 166 } :user 167 168 . = ALIGN(L1_CACHE_BYTES); 169 .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { 170 *(.vsyscall_fn) 171 } 172 173 . = ALIGN(L1_CACHE_BYTES); 174 .vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) { 175 *(.vsyscall_gtod_data) 176 } 177 178 vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data); 179 .vsyscall_clock : AT(VLOAD(.vsyscall_clock)) { 180 *(.vsyscall_clock) 181 } 182 vsyscall_clock = VVIRT(.vsyscall_clock); 183 184 185 .vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { 186 *(.vsyscall_1) 187 } 188 .vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) { 189 *(.vsyscall_2) 190 } 191 192 .vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) { 193 *(.vgetcpu_mode) 194 } 195 vgetcpu_mode = VVIRT(.vgetcpu_mode); 196 197 . = ALIGN(L1_CACHE_BYTES); 198 .jiffies : AT(VLOAD(.jiffies)) { 199 *(.jiffies) 200 } 201 jiffies = VVIRT(.jiffies); 202 203 .vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { 204 *(.vsyscall_3) 205 } 206 207 . = __vsyscall_0 + PAGE_SIZE; 208 209#undef VSYSCALL_ADDR 210#undef VLOAD_OFFSET 211#undef VLOAD 212#undef VVIRT_OFFSET 213#undef VVIRT 214 215#endif /* CONFIG_X86_64 */ 216 217 /* Init code and data - will be freed after init */ 218 . = ALIGN(PAGE_SIZE); 219 .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { 220 __init_begin = .; /* paired with __init_end */ 221 } 222 223#if defined(CONFIG_X86_64) && defined(CONFIG_SMP) 224 /* 225 * percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the 226 * output PHDR, so the next output section - .init.text - should 227 * start another segment - init. 228 */ 229 PERCPU_VADDR(0, :percpu) 230#endif 231 232 INIT_TEXT_SECTION(PAGE_SIZE) 233#ifdef CONFIG_X86_64 234 :init 235#endif 236 237 INIT_DATA_SECTION(16) 238 239 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 240 __x86_cpu_dev_start = .; 241 *(.x86_cpu_dev.init) 242 __x86_cpu_dev_end = .; 243 } 244 245 /* 246 * start address and size of operations which during runtime 247 * can be patched with virtualization friendly instructions or 248 * baremetal native ones. Think page table operations. 249 * Details in paravirt_types.h 250 */ 251 . = ALIGN(8); 252 .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { 253 __parainstructions = .; 254 *(.parainstructions) 255 __parainstructions_end = .; 256 } 257 258 /* 259 * struct alt_inst entries. From the header (alternative.h): 260 * "Alternative instructions for different CPU types or capabilities" 261 * Think locking instructions on spinlocks. 262 */ 263 . = ALIGN(8); 264 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 265 __alt_instructions = .; 266 *(.altinstructions) 267 __alt_instructions_end = .; 268 } 269 270 /* 271 * And here are the replacement instructions. The linker sticks 272 * them as binary blobs. The .altinstructions has enough data to 273 * get the address and the length of them to patch the kernel safely. 274 */ 275 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 276 *(.altinstr_replacement) 277 } 278 279 /* 280 * struct iommu_table_entry entries are injected in this section. 281 * It is an array of IOMMUs which during run time gets sorted depending 282 * on its dependency order. After rootfs_initcall is complete 283 * this section can be safely removed. 284 */ 285 .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { 286 __iommu_table = .; 287 *(.iommu_table) 288 __iommu_table_end = .; 289 } 290 . = ALIGN(8); 291 /* 292 * .exit.text is discard at runtime, not link time, to deal with 293 * references from .altinstructions and .eh_frame 294 */ 295 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 296 EXIT_TEXT 297 } 298 299 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 300 EXIT_DATA 301 } 302 303#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) 304 PERCPU(THREAD_SIZE) 305#endif 306 307 . = ALIGN(PAGE_SIZE); 308 309 /* freed after init ends here */ 310 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 311 __init_end = .; 312 } 313 314 /* 315 * smp_locks might be freed after init 316 * start/end must be page aligned 317 */ 318 . = ALIGN(PAGE_SIZE); 319 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 320 __smp_locks = .; 321 *(.smp_locks) 322 . = ALIGN(PAGE_SIZE); 323 __smp_locks_end = .; 324 } 325 326#ifdef CONFIG_X86_64 327 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 328 NOSAVE_DATA 329 } 330#endif 331 332 /* BSS */ 333 . = ALIGN(PAGE_SIZE); 334 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 335 __bss_start = .; 336 *(.bss..page_aligned) 337 *(.bss) 338 . = ALIGN(4); 339 __bss_stop = .; 340 } 341 342 . = ALIGN(PAGE_SIZE); 343 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 344 __brk_base = .; 345 . += 64 * 1024; /* 64k alignment slop space */ 346 *(.brk_reservation) /* areas brk users have reserved */ 347 __brk_limit = .; 348 } 349 350 _end = .; 351 352 STABS_DEBUG 353 DWARF_DEBUG 354 355 /* Sections to be discarded */ 356 DISCARDS 357 /DISCARD/ : { *(.eh_frame) } 358} 359 360 361#ifdef CONFIG_X86_32 362/* 363 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: 364 */ 365. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 366 "kernel image bigger than KERNEL_IMAGE_SIZE"); 367#else 368/* 369 * Per-cpu symbols which need to be offset from __per_cpu_load 370 * for the boot processor. 371 */ 372#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load 373INIT_PER_CPU(gdt_page); 374INIT_PER_CPU(irq_stack_union); 375 376/* 377 * Build-time check on the image size: 378 */ 379. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), 380 "kernel image bigger than KERNEL_IMAGE_SIZE"); 381 382#ifdef CONFIG_SMP 383. = ASSERT((irq_stack_union == 0), 384 "irq_stack_union is not at start of per-cpu area"); 385#endif 386 387#endif /* CONFIG_X86_32 */ 388 389#ifdef CONFIG_KEXEC 390#include <asm/kexec.h> 391 392. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, 393 "kexec control code size is too big"); 394#endif 395 396