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) 45/* 46 * On 64-bit, align RODATA to 2MB so we retain large page mappings for 47 * boundaries spanning kernel text, rodata and data sections. 48 * 49 * However, kernel identity mappings will have different RWX permissions 50 * to the pages mapping to text and to the pages padding (which are freed) the 51 * text section. Hence kernel identity mappings will be broken to smaller 52 * pages. For 64-bit, kernel text and kernel identity mappings are different, 53 * so we can enable protection checks as well as retain 2MB large page 54 * mappings for kernel text. 55 */ 56#define X64_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); 57 58#define X64_ALIGN_RODATA_END \ 59 . = ALIGN(HPAGE_SIZE); \ 60 __end_rodata_hpage_align = .; 61 62#else 63 64#define X64_ALIGN_RODATA_BEGIN 65#define X64_ALIGN_RODATA_END 66 67#endif 68 69PHDRS { 70 text PT_LOAD FLAGS(5); /* R_E */ 71 data PT_LOAD FLAGS(6); /* RW_ */ 72#ifdef CONFIG_X86_64 73#ifdef CONFIG_SMP 74 percpu PT_LOAD FLAGS(6); /* RW_ */ 75#endif 76 init PT_LOAD FLAGS(7); /* RWE */ 77#endif 78 note PT_NOTE FLAGS(0); /* ___ */ 79} 80 81SECTIONS 82{ 83#ifdef CONFIG_X86_32 84 . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR; 85 phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET); 86#else 87 . = __START_KERNEL; 88 phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET); 89#endif 90 91 /* Text and read-only data */ 92 .text : AT(ADDR(.text) - LOAD_OFFSET) { 93 _text = .; 94 _stext = .; 95 /* bootstrapping code */ 96 HEAD_TEXT 97 . = ALIGN(8); 98 TEXT_TEXT 99 SCHED_TEXT 100 CPUIDLE_TEXT 101 LOCK_TEXT 102 KPROBES_TEXT 103 ENTRY_TEXT 104 IRQENTRY_TEXT 105 SOFTIRQENTRY_TEXT 106 *(.fixup) 107 *(.gnu.warning) 108 /* End of text section */ 109 _etext = .; 110 } :text = 0x9090 111 112 NOTES :text :note 113 114 EXCEPTION_TABLE(16) :text = 0x9090 115 116 /* .text should occupy whole number of pages */ 117 . = ALIGN(PAGE_SIZE); 118 X64_ALIGN_RODATA_BEGIN 119 RO_DATA(PAGE_SIZE) 120 X64_ALIGN_RODATA_END 121 122 /* Data */ 123 .data : AT(ADDR(.data) - LOAD_OFFSET) { 124 /* Start of data section */ 125 _sdata = .; 126 127 /* init_task */ 128 INIT_TASK_DATA(THREAD_SIZE) 129 130#ifdef CONFIG_X86_32 131 /* 32 bit has nosave before _edata */ 132 NOSAVE_DATA 133#endif 134 135 PAGE_ALIGNED_DATA(PAGE_SIZE) 136 137 CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) 138 139 DATA_DATA 140 CONSTRUCTORS 141 142 /* rarely changed data like cpu maps */ 143 READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES) 144 145 /* End of data section */ 146 _edata = .; 147 } :data 148 149 BUG_TABLE 150 151 . = ALIGN(PAGE_SIZE); 152 __vvar_page = .; 153 154 .vvar : AT(ADDR(.vvar) - LOAD_OFFSET) { 155 /* work around gold bug 13023 */ 156 __vvar_beginning_hack = .; 157 158 /* Place all vvars at the offsets in asm/vvar.h. */ 159#define EMIT_VVAR(name, offset) \ 160 . = __vvar_beginning_hack + offset; \ 161 *(.vvar_ ## name) 162#define __VVAR_KERNEL_LDS 163#include <asm/vvar.h> 164#undef __VVAR_KERNEL_LDS 165#undef EMIT_VVAR 166 167 /* 168 * Pad the rest of the page with zeros. Otherwise the loader 169 * can leave garbage here. 170 */ 171 . = __vvar_beginning_hack + PAGE_SIZE; 172 } :data 173 174 . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE); 175 176 /* Init code and data - will be freed after init */ 177 . = ALIGN(PAGE_SIZE); 178 .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { 179 __init_begin = .; /* paired with __init_end */ 180 } 181 182#if defined(CONFIG_X86_64) && defined(CONFIG_SMP) 183 /* 184 * percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the 185 * output PHDR, so the next output section - .init.text - should 186 * start another segment - init. 187 */ 188 PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu) 189 ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START, 190 "per-CPU data too large - increase CONFIG_PHYSICAL_START") 191#endif 192 193 INIT_TEXT_SECTION(PAGE_SIZE) 194#ifdef CONFIG_X86_64 195 :init 196#endif 197 198 /* 199 * Section for code used exclusively before alternatives are run. All 200 * references to such code must be patched out by alternatives, normally 201 * by using X86_FEATURE_ALWAYS CPU feature bit. 202 * 203 * See static_cpu_has() for an example. 204 */ 205 .altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) { 206 *(.altinstr_aux) 207 } 208 209 INIT_DATA_SECTION(16) 210 211 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 212 __x86_cpu_dev_start = .; 213 *(.x86_cpu_dev.init) 214 __x86_cpu_dev_end = .; 215 } 216 217#ifdef CONFIG_X86_INTEL_MID 218 .x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \ 219 LOAD_OFFSET) { 220 __x86_intel_mid_dev_start = .; 221 *(.x86_intel_mid_dev.init) 222 __x86_intel_mid_dev_end = .; 223 } 224#endif 225 226 /* 227 * start address and size of operations which during runtime 228 * can be patched with virtualization friendly instructions or 229 * baremetal native ones. Think page table operations. 230 * Details in paravirt_types.h 231 */ 232 . = ALIGN(8); 233 .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { 234 __parainstructions = .; 235 *(.parainstructions) 236 __parainstructions_end = .; 237 } 238 239 /* 240 * struct alt_inst entries. From the header (alternative.h): 241 * "Alternative instructions for different CPU types or capabilities" 242 * Think locking instructions on spinlocks. 243 */ 244 . = ALIGN(8); 245 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 246 __alt_instructions = .; 247 *(.altinstructions) 248 __alt_instructions_end = .; 249 } 250 251 /* 252 * And here are the replacement instructions. The linker sticks 253 * them as binary blobs. The .altinstructions has enough data to 254 * get the address and the length of them to patch the kernel safely. 255 */ 256 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 257 *(.altinstr_replacement) 258 } 259 260 /* 261 * struct iommu_table_entry entries are injected in this section. 262 * It is an array of IOMMUs which during run time gets sorted depending 263 * on its dependency order. After rootfs_initcall is complete 264 * this section can be safely removed. 265 */ 266 .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { 267 __iommu_table = .; 268 *(.iommu_table) 269 __iommu_table_end = .; 270 } 271 272 . = ALIGN(8); 273 .apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) { 274 __apicdrivers = .; 275 *(.apicdrivers); 276 __apicdrivers_end = .; 277 } 278 279 . = ALIGN(8); 280 /* 281 * .exit.text is discard at runtime, not link time, to deal with 282 * references from .altinstructions and .eh_frame 283 */ 284 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 285 EXIT_TEXT 286 } 287 288 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 289 EXIT_DATA 290 } 291 292#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) 293 PERCPU_SECTION(INTERNODE_CACHE_BYTES) 294#endif 295 296 . = ALIGN(PAGE_SIZE); 297 298 /* freed after init ends here */ 299 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 300 __init_end = .; 301 } 302 303 /* 304 * smp_locks might be freed after init 305 * start/end must be page aligned 306 */ 307 . = ALIGN(PAGE_SIZE); 308 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 309 __smp_locks = .; 310 *(.smp_locks) 311 . = ALIGN(PAGE_SIZE); 312 __smp_locks_end = .; 313 } 314 315#ifdef CONFIG_X86_64 316 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 317 NOSAVE_DATA 318 } 319#endif 320 321 /* BSS */ 322 . = ALIGN(PAGE_SIZE); 323 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 324 __bss_start = .; 325 *(.bss..page_aligned) 326 *(.bss) 327 . = ALIGN(PAGE_SIZE); 328 __bss_stop = .; 329 } 330 331 . = ALIGN(PAGE_SIZE); 332 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 333 __brk_base = .; 334 . += 64 * 1024; /* 64k alignment slop space */ 335 *(.brk_reservation) /* areas brk users have reserved */ 336 __brk_limit = .; 337 } 338 339 . = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */ 340 _end = .; 341 342 STABS_DEBUG 343 DWARF_DEBUG 344 345 /* Sections to be discarded */ 346 DISCARDS 347 /DISCARD/ : { 348 *(.eh_frame) 349 } 350} 351 352 353#ifdef CONFIG_X86_32 354/* 355 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: 356 */ 357. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 358 "kernel image bigger than KERNEL_IMAGE_SIZE"); 359#else 360/* 361 * Per-cpu symbols which need to be offset from __per_cpu_load 362 * for the boot processor. 363 */ 364#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load 365INIT_PER_CPU(gdt_page); 366INIT_PER_CPU(irq_stack_union); 367 368/* 369 * Build-time check on the image size: 370 */ 371. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), 372 "kernel image bigger than KERNEL_IMAGE_SIZE"); 373 374#ifdef CONFIG_SMP 375. = ASSERT((irq_stack_union == 0), 376 "irq_stack_union is not at start of per-cpu area"); 377#endif 378 379#endif /* CONFIG_X86_32 */ 380 381#ifdef CONFIG_KEXEC_CORE 382#include <asm/kexec.h> 383 384. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, 385 "kexec control code size is too big"); 386#endif 387 388