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#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 = startup_32 - LOAD_OFFSET; 87#else 88 . = __START_KERNEL; 89 phys_startup_64 = startup_64 - LOAD_OFFSET; 90#endif 91 92 /* Text and read-only data */ 93 .text : AT(ADDR(.text) - LOAD_OFFSET) { 94 _text = .; 95 /* bootstrapping code */ 96 HEAD_TEXT 97 . = ALIGN(8); 98 _stext = .; 99 TEXT_TEXT 100 SCHED_TEXT 101 LOCK_TEXT 102 KPROBES_TEXT 103 ENTRY_TEXT 104 IRQENTRY_TEXT 105 *(.fixup) 106 *(.gnu.warning) 107 /* End of text section */ 108 _etext = .; 109 } :text = 0x9090 110 111 NOTES :text :note 112 113 EXCEPTION_TABLE(16) :text = 0x9090 114 115#if defined(CONFIG_DEBUG_RODATA) 116 /* .text should occupy whole number of pages */ 117 . = ALIGN(PAGE_SIZE); 118#endif 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 149 150 151 . = 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 INIT_DATA_SECTION(16) 199 200 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 201 __x86_cpu_dev_start = .; 202 *(.x86_cpu_dev.init) 203 __x86_cpu_dev_end = .; 204 } 205 206#ifdef CONFIG_X86_INTEL_MID 207 .x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \ 208 LOAD_OFFSET) { 209 __x86_intel_mid_dev_start = .; 210 *(.x86_intel_mid_dev.init) 211 __x86_intel_mid_dev_end = .; 212 } 213#endif 214 215 /* 216 * start address and size of operations which during runtime 217 * can be patched with virtualization friendly instructions or 218 * baremetal native ones. Think page table operations. 219 * Details in paravirt_types.h 220 */ 221 . = ALIGN(8); 222 .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { 223 __parainstructions = .; 224 *(.parainstructions) 225 __parainstructions_end = .; 226 } 227 228 /* 229 * struct alt_inst entries. From the header (alternative.h): 230 * "Alternative instructions for different CPU types or capabilities" 231 * Think locking instructions on spinlocks. 232 */ 233 . = ALIGN(8); 234 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 235 __alt_instructions = .; 236 *(.altinstructions) 237 __alt_instructions_end = .; 238 } 239 240 /* 241 * And here are the replacement instructions. The linker sticks 242 * them as binary blobs. The .altinstructions has enough data to 243 * get the address and the length of them to patch the kernel safely. 244 */ 245 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 246 *(.altinstr_replacement) 247 } 248 249 /* 250 * struct iommu_table_entry entries are injected in this section. 251 * It is an array of IOMMUs which during run time gets sorted depending 252 * on its dependency order. After rootfs_initcall is complete 253 * this section can be safely removed. 254 */ 255 .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { 256 __iommu_table = .; 257 *(.iommu_table) 258 __iommu_table_end = .; 259 } 260 261 . = ALIGN(8); 262 .apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) { 263 __apicdrivers = .; 264 *(.apicdrivers); 265 __apicdrivers_end = .; 266 } 267 268 . = ALIGN(8); 269 /* 270 * .exit.text is discard at runtime, not link time, to deal with 271 * references from .altinstructions and .eh_frame 272 */ 273 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 274 EXIT_TEXT 275 } 276 277 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 278 EXIT_DATA 279 } 280 281#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) 282 PERCPU_SECTION(INTERNODE_CACHE_BYTES) 283#endif 284 285 . = ALIGN(PAGE_SIZE); 286 287 /* freed after init ends here */ 288 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 289 __init_end = .; 290 } 291 292 /* 293 * smp_locks might be freed after init 294 * start/end must be page aligned 295 */ 296 . = ALIGN(PAGE_SIZE); 297 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 298 __smp_locks = .; 299 *(.smp_locks) 300 . = ALIGN(PAGE_SIZE); 301 __smp_locks_end = .; 302 } 303 304#ifdef CONFIG_X86_64 305 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 306 NOSAVE_DATA 307 } 308#endif 309 310 /* BSS */ 311 . = ALIGN(PAGE_SIZE); 312 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 313 __bss_start = .; 314 *(.bss..page_aligned) 315 *(.bss) 316 . = ALIGN(PAGE_SIZE); 317 __bss_stop = .; 318 } 319 320 . = ALIGN(PAGE_SIZE); 321 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 322 __brk_base = .; 323 . += 64 * 1024; /* 64k alignment slop space */ 324 *(.brk_reservation) /* areas brk users have reserved */ 325 __brk_limit = .; 326 } 327 328 _end = .; 329 330 STABS_DEBUG 331 DWARF_DEBUG 332 333 /* Sections to be discarded */ 334 DISCARDS 335 /DISCARD/ : { *(.eh_frame) } 336} 337 338 339#ifdef CONFIG_X86_32 340/* 341 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: 342 */ 343. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 344 "kernel image bigger than KERNEL_IMAGE_SIZE"); 345#else 346/* 347 * Per-cpu symbols which need to be offset from __per_cpu_load 348 * for the boot processor. 349 */ 350#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load 351INIT_PER_CPU(gdt_page); 352INIT_PER_CPU(irq_stack_union); 353 354/* 355 * Build-time check on the image size: 356 */ 357. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), 358 "kernel image bigger than KERNEL_IMAGE_SIZE"); 359 360#ifdef CONFIG_SMP 361. = ASSERT((irq_stack_union == 0), 362 "irq_stack_union is not at start of per-cpu area"); 363#endif 364 365#endif /* CONFIG_X86_32 */ 366 367#ifdef CONFIG_KEXEC 368#include <asm/kexec.h> 369 370. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, 371 "kexec control code size is too big"); 372#endif 373 374