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(6); /* RW_ */ 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 ENTRY_TEXT 109 IRQENTRY_TEXT 110 *(.fixup) 111 *(.gnu.warning) 112 /* End of text section */ 113 _etext = .; 114 } :text = 0x9090 115 116 NOTES :text :note 117 118 EXCEPTION_TABLE(16) :text = 0x9090 119 120#if defined(CONFIG_DEBUG_RODATA) 121 /* .text should occupy whole number of pages */ 122 . = ALIGN(PAGE_SIZE); 123#endif 124 X64_ALIGN_DEBUG_RODATA_BEGIN 125 RO_DATA(PAGE_SIZE) 126 X64_ALIGN_DEBUG_RODATA_END 127 128 /* Data */ 129 .data : AT(ADDR(.data) - LOAD_OFFSET) { 130 /* Start of data section */ 131 _sdata = .; 132 133 /* init_task */ 134 INIT_TASK_DATA(THREAD_SIZE) 135 136#ifdef CONFIG_X86_32 137 /* 32 bit has nosave before _edata */ 138 NOSAVE_DATA 139#endif 140 141 PAGE_ALIGNED_DATA(PAGE_SIZE) 142 143 CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) 144 145 DATA_DATA 146 CONSTRUCTORS 147 148 /* rarely changed data like cpu maps */ 149 READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES) 150 151 /* End of data section */ 152 _edata = .; 153 } :data 154 155#ifdef CONFIG_X86_64 156 157#define VSYSCALL_ADDR (-10*1024*1024) 158 159#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET) 160#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET) 161 162#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0) 163#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET) 164#define EMIT_VVAR(x, offset) .vsyscall_var_ ## x \ 165 ADDR(.vsyscall_0) + offset \ 166 : AT(VLOAD(.vsyscall_var_ ## x)) { \ 167 *(.vsyscall_var_ ## x) \ 168 } \ 169 x = VVIRT(.vsyscall_var_ ## x); 170 171 . = ALIGN(4096); 172 __vsyscall_0 = .; 173 174 . = VSYSCALL_ADDR; 175 .vsyscall_0 : AT(VLOAD(.vsyscall_0)) { 176 *(.vsyscall_0) 177 } :user 178 179 . = ALIGN(L1_CACHE_BYTES); 180 .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { 181 *(.vsyscall_fn) 182 } 183 184 .vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { 185 *(.vsyscall_1) 186 } 187 .vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) { 188 *(.vsyscall_2) 189 } 190 191 .vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { 192 *(.vsyscall_3) 193 } 194 195#define __VVAR_KERNEL_LDS 196#include <asm/vvar.h> 197#undef __VVAR_KERNEL_LDS 198 199 . = __vsyscall_0 + PAGE_SIZE; 200 201#undef VSYSCALL_ADDR 202#undef VLOAD_OFFSET 203#undef VLOAD 204#undef VVIRT_OFFSET 205#undef VVIRT 206#undef EMIT_VVAR 207 208#endif /* CONFIG_X86_64 */ 209 210 /* Init code and data - will be freed after init */ 211 . = ALIGN(PAGE_SIZE); 212 .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { 213 __init_begin = .; /* paired with __init_end */ 214 } 215 216#if defined(CONFIG_X86_64) && defined(CONFIG_SMP) 217 /* 218 * percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the 219 * output PHDR, so the next output section - .init.text - should 220 * start another segment - init. 221 */ 222 PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu) 223#endif 224 225 INIT_TEXT_SECTION(PAGE_SIZE) 226#ifdef CONFIG_X86_64 227 :init 228#endif 229 230 INIT_DATA_SECTION(16) 231 232 /* 233 * Code and data for a variety of lowlevel trampolines, to be 234 * copied into base memory (< 1 MiB) during initialization. 235 * Since it is copied early, the main copy can be discarded 236 * afterwards. 237 */ 238 .x86_trampoline : AT(ADDR(.x86_trampoline) - LOAD_OFFSET) { 239 x86_trampoline_start = .; 240 *(.x86_trampoline) 241 x86_trampoline_end = .; 242 } 243 244 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 245 __x86_cpu_dev_start = .; 246 *(.x86_cpu_dev.init) 247 __x86_cpu_dev_end = .; 248 } 249 250 /* 251 * start address and size of operations which during runtime 252 * can be patched with virtualization friendly instructions or 253 * baremetal native ones. Think page table operations. 254 * Details in paravirt_types.h 255 */ 256 . = ALIGN(8); 257 .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { 258 __parainstructions = .; 259 *(.parainstructions) 260 __parainstructions_end = .; 261 } 262 263 /* 264 * struct alt_inst entries. From the header (alternative.h): 265 * "Alternative instructions for different CPU types or capabilities" 266 * Think locking instructions on spinlocks. 267 */ 268 . = ALIGN(8); 269 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 270 __alt_instructions = .; 271 *(.altinstructions) 272 __alt_instructions_end = .; 273 } 274 275 /* 276 * And here are the replacement instructions. The linker sticks 277 * them as binary blobs. The .altinstructions has enough data to 278 * get the address and the length of them to patch the kernel safely. 279 */ 280 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 281 *(.altinstr_replacement) 282 } 283 284 /* 285 * struct iommu_table_entry entries are injected in this section. 286 * It is an array of IOMMUs which during run time gets sorted depending 287 * on its dependency order. After rootfs_initcall is complete 288 * this section can be safely removed. 289 */ 290 .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { 291 __iommu_table = .; 292 *(.iommu_table) 293 __iommu_table_end = .; 294 } 295 296 . = ALIGN(8); 297 .apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) { 298 __apicdrivers = .; 299 *(.apicdrivers); 300 __apicdrivers_end = .; 301 } 302 303 . = ALIGN(8); 304 /* 305 * .exit.text is discard at runtime, not link time, to deal with 306 * references from .altinstructions and .eh_frame 307 */ 308 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 309 EXIT_TEXT 310 } 311 312 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 313 EXIT_DATA 314 } 315 316#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) 317 PERCPU_SECTION(INTERNODE_CACHE_BYTES) 318#endif 319 320 . = ALIGN(PAGE_SIZE); 321 322 /* freed after init ends here */ 323 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 324 __init_end = .; 325 } 326 327 /* 328 * smp_locks might be freed after init 329 * start/end must be page aligned 330 */ 331 . = ALIGN(PAGE_SIZE); 332 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 333 __smp_locks = .; 334 *(.smp_locks) 335 . = ALIGN(PAGE_SIZE); 336 __smp_locks_end = .; 337 } 338 339#ifdef CONFIG_X86_64 340 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 341 NOSAVE_DATA 342 } 343#endif 344 345 /* BSS */ 346 . = ALIGN(PAGE_SIZE); 347 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 348 __bss_start = .; 349 *(.bss..page_aligned) 350 *(.bss) 351 . = ALIGN(PAGE_SIZE); 352 __bss_stop = .; 353 } 354 355 . = ALIGN(PAGE_SIZE); 356 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 357 __brk_base = .; 358 . += 64 * 1024; /* 64k alignment slop space */ 359 *(.brk_reservation) /* areas brk users have reserved */ 360 __brk_limit = .; 361 } 362 363 _end = .; 364 365 STABS_DEBUG 366 DWARF_DEBUG 367 368 /* Sections to be discarded */ 369 DISCARDS 370 /DISCARD/ : { *(.eh_frame) } 371} 372 373 374#ifdef CONFIG_X86_32 375/* 376 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: 377 */ 378. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 379 "kernel image bigger than KERNEL_IMAGE_SIZE"); 380#else 381/* 382 * Per-cpu symbols which need to be offset from __per_cpu_load 383 * for the boot processor. 384 */ 385#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load 386INIT_PER_CPU(gdt_page); 387INIT_PER_CPU(irq_stack_union); 388 389/* 390 * Build-time check on the image size: 391 */ 392. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), 393 "kernel image bigger than KERNEL_IMAGE_SIZE"); 394 395#ifdef CONFIG_SMP 396. = ASSERT((irq_stack_union == 0), 397 "irq_stack_union is not at start of per-cpu area"); 398#endif 399 400#endif /* CONFIG_X86_32 */ 401 402#ifdef CONFIG_KEXEC 403#include <asm/kexec.h> 404 405. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, 406 "kexec control code size is too big"); 407#endif 408 409