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/orc_lookup.h> 28#include <asm/cache.h> 29#include <asm/boot.h> 30 31#undef i386 /* in case the preprocessor is a 32bit one */ 32 33OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT) 34 35#ifdef CONFIG_X86_32 36OUTPUT_ARCH(i386) 37ENTRY(phys_startup_32) 38jiffies = jiffies_64; 39#else 40OUTPUT_ARCH(i386:x86-64) 41ENTRY(phys_startup_64) 42jiffies_64 = jiffies; 43#endif 44 45#if defined(CONFIG_X86_64) 46/* 47 * On 64-bit, align RODATA to 2MB so we retain large page mappings for 48 * boundaries spanning kernel text, rodata 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 as well as retain 2MB large page 55 * mappings for kernel text. 56 */ 57#define X64_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); 58 59#define X64_ALIGN_RODATA_END \ 60 . = ALIGN(HPAGE_SIZE); \ 61 __end_rodata_hpage_align = .; 62 63#else 64 65#define X64_ALIGN_RODATA_BEGIN 66#define X64_ALIGN_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#ifdef CONFIG_SMP 75 percpu PT_LOAD FLAGS(6); /* RW_ */ 76#endif 77 init PT_LOAD FLAGS(7); /* RWE */ 78#endif 79 note PT_NOTE FLAGS(0); /* ___ */ 80} 81 82SECTIONS 83{ 84#ifdef CONFIG_X86_32 85 . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR; 86 phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET); 87#else 88 . = __START_KERNEL; 89 phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET); 90#endif 91 92 /* Text and read-only data */ 93 .text : AT(ADDR(.text) - LOAD_OFFSET) { 94 _text = .; 95 _stext = .; 96 /* bootstrapping code */ 97 HEAD_TEXT 98 . = ALIGN(8); 99 TEXT_TEXT 100 SCHED_TEXT 101 CPUIDLE_TEXT 102 LOCK_TEXT 103 KPROBES_TEXT 104 ENTRY_TEXT 105 IRQENTRY_TEXT 106 SOFTIRQENTRY_TEXT 107 *(.fixup) 108 *(.gnu.warning) 109 /* End of text section */ 110 _etext = .; 111 } :text = 0x9090 112 113 NOTES :text :note 114 115 EXCEPTION_TABLE(16) :text = 0x9090 116 117 /* .text should occupy whole number of pages */ 118 . = ALIGN(PAGE_SIZE); 119 X64_ALIGN_RODATA_BEGIN 120 RO_DATA(PAGE_SIZE) 121 X64_ALIGN_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 BUG_TABLE 151 152 ORC_UNWIND_TABLE 153 154 . = ALIGN(PAGE_SIZE); 155 __vvar_page = .; 156 157 .vvar : AT(ADDR(.vvar) - LOAD_OFFSET) { 158 /* work around gold bug 13023 */ 159 __vvar_beginning_hack = .; 160 161 /* Place all vvars at the offsets in asm/vvar.h. */ 162#define EMIT_VVAR(name, offset) \ 163 . = __vvar_beginning_hack + offset; \ 164 *(.vvar_ ## name) 165#define __VVAR_KERNEL_LDS 166#include <asm/vvar.h> 167#undef __VVAR_KERNEL_LDS 168#undef EMIT_VVAR 169 170 /* 171 * Pad the rest of the page with zeros. Otherwise the loader 172 * can leave garbage here. 173 */ 174 . = __vvar_beginning_hack + PAGE_SIZE; 175 } :data 176 177 . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE); 178 179 /* Init code and data - will be freed after init */ 180 . = ALIGN(PAGE_SIZE); 181 .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { 182 __init_begin = .; /* paired with __init_end */ 183 } 184 185#if defined(CONFIG_X86_64) && defined(CONFIG_SMP) 186 /* 187 * percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the 188 * output PHDR, so the next output section - .init.text - should 189 * start another segment - init. 190 */ 191 PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu) 192 ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START, 193 "per-CPU data too large - increase CONFIG_PHYSICAL_START") 194#endif 195 196 INIT_TEXT_SECTION(PAGE_SIZE) 197#ifdef CONFIG_X86_64 198 :init 199#endif 200 201 /* 202 * Section for code used exclusively before alternatives are run. All 203 * references to such code must be patched out by alternatives, normally 204 * by using X86_FEATURE_ALWAYS CPU feature bit. 205 * 206 * See static_cpu_has() for an example. 207 */ 208 .altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) { 209 *(.altinstr_aux) 210 } 211 212 INIT_DATA_SECTION(16) 213 214 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 215 __x86_cpu_dev_start = .; 216 *(.x86_cpu_dev.init) 217 __x86_cpu_dev_end = .; 218 } 219 220#ifdef CONFIG_X86_INTEL_MID 221 .x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \ 222 LOAD_OFFSET) { 223 __x86_intel_mid_dev_start = .; 224 *(.x86_intel_mid_dev.init) 225 __x86_intel_mid_dev_end = .; 226 } 227#endif 228 229 /* 230 * start address and size of operations which during runtime 231 * can be patched with virtualization friendly instructions or 232 * baremetal native ones. Think page table operations. 233 * Details in paravirt_types.h 234 */ 235 . = ALIGN(8); 236 .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { 237 __parainstructions = .; 238 *(.parainstructions) 239 __parainstructions_end = .; 240 } 241 242 /* 243 * struct alt_inst entries. From the header (alternative.h): 244 * "Alternative instructions for different CPU types or capabilities" 245 * Think locking instructions on spinlocks. 246 */ 247 . = ALIGN(8); 248 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 249 __alt_instructions = .; 250 *(.altinstructions) 251 __alt_instructions_end = .; 252 } 253 254 /* 255 * And here are the replacement instructions. The linker sticks 256 * them as binary blobs. The .altinstructions has enough data to 257 * get the address and the length of them to patch the kernel safely. 258 */ 259 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 260 *(.altinstr_replacement) 261 } 262 263 /* 264 * struct iommu_table_entry entries are injected in this section. 265 * It is an array of IOMMUs which during run time gets sorted depending 266 * on its dependency order. After rootfs_initcall is complete 267 * this section can be safely removed. 268 */ 269 .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { 270 __iommu_table = .; 271 *(.iommu_table) 272 __iommu_table_end = .; 273 } 274 275 . = ALIGN(8); 276 .apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) { 277 __apicdrivers = .; 278 *(.apicdrivers); 279 __apicdrivers_end = .; 280 } 281 282 . = ALIGN(8); 283 /* 284 * .exit.text is discard at runtime, not link time, to deal with 285 * references from .altinstructions and .eh_frame 286 */ 287 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 288 EXIT_TEXT 289 } 290 291 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 292 EXIT_DATA 293 } 294 295#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) 296 PERCPU_SECTION(INTERNODE_CACHE_BYTES) 297#endif 298 299 . = ALIGN(PAGE_SIZE); 300 301 /* freed after init ends here */ 302 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 303 __init_end = .; 304 } 305 306 /* 307 * smp_locks might be freed after init 308 * start/end must be page aligned 309 */ 310 . = ALIGN(PAGE_SIZE); 311 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 312 __smp_locks = .; 313 *(.smp_locks) 314 . = ALIGN(PAGE_SIZE); 315 __smp_locks_end = .; 316 } 317 318#ifdef CONFIG_X86_64 319 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 320 NOSAVE_DATA 321 } 322#endif 323 324 /* BSS */ 325 . = ALIGN(PAGE_SIZE); 326 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 327 __bss_start = .; 328 *(.bss..page_aligned) 329 *(.bss) 330 . = ALIGN(PAGE_SIZE); 331 __bss_stop = .; 332 } 333 334 . = ALIGN(PAGE_SIZE); 335 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 336 __brk_base = .; 337 . += 64 * 1024; /* 64k alignment slop space */ 338 *(.brk_reservation) /* areas brk users have reserved */ 339 __brk_limit = .; 340 } 341 342 . = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */ 343 _end = .; 344 345 STABS_DEBUG 346 DWARF_DEBUG 347 348 /* Sections to be discarded */ 349 DISCARDS 350 /DISCARD/ : { 351 *(.eh_frame) 352 } 353} 354 355 356#ifdef CONFIG_X86_32 357/* 358 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: 359 */ 360. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 361 "kernel image bigger than KERNEL_IMAGE_SIZE"); 362#else 363/* 364 * Per-cpu symbols which need to be offset from __per_cpu_load 365 * for the boot processor. 366 */ 367#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load 368INIT_PER_CPU(gdt_page); 369INIT_PER_CPU(irq_stack_union); 370 371/* 372 * Build-time check on the image size: 373 */ 374. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), 375 "kernel image bigger than KERNEL_IMAGE_SIZE"); 376 377#ifdef CONFIG_SMP 378. = ASSERT((irq_stack_union == 0), 379 "irq_stack_union is not at start of per-cpu area"); 380#endif 381 382#endif /* CONFIG_X86_32 */ 383 384#ifdef CONFIG_KEXEC_CORE 385#include <asm/kexec.h> 386 387. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, 388 "kexec control code size is too big"); 389#endif 390 391