1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * ld script for the x86 kernel 4 * 5 * Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz> 6 * 7 * Modernisation, unification and other changes and fixes: 8 * Copyright (C) 2007-2009 Sam Ravnborg <sam@ravnborg.org> 9 * 10 * 11 * Don't define absolute symbols until and unless you know that symbol 12 * value is should remain constant even if kernel image is relocated 13 * at run time. Absolute symbols are not relocated. If symbol value should 14 * change if kernel is relocated, make the symbol section relative and 15 * put it inside the section definition. 16 */ 17 18#define LOAD_OFFSET __START_KERNEL_map 19 20#define RUNTIME_DISCARD_EXIT 21#define EMITS_PT_NOTE 22#define RO_EXCEPTION_TABLE_ALIGN 16 23 24#include <asm-generic/vmlinux.lds.h> 25#include <asm/asm-offsets.h> 26#include <asm/thread_info.h> 27#include <asm/page_types.h> 28#include <asm/orc_lookup.h> 29#include <asm/cache.h> 30#include <asm/boot.h> 31#include <asm/kexec.h> 32 33#undef i386 /* in case the preprocessor is a 32bit one */ 34 35OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT) 36 37#ifdef CONFIG_X86_32 38OUTPUT_ARCH(i386) 39ENTRY(phys_startup_32) 40#else 41OUTPUT_ARCH(i386:x86-64) 42ENTRY(phys_startup_64) 43#endif 44 45jiffies = jiffies_64; 46const_current_task = current_task; 47const_cpu_current_top_of_stack = cpu_current_top_of_stack; 48 49#if defined(CONFIG_X86_64) 50/* 51 * On 64-bit, align RODATA to 2MB so we retain large page mappings for 52 * boundaries spanning kernel text, rodata and data sections. 53 * 54 * However, kernel identity mappings will have different RWX permissions 55 * to the pages mapping to text and to the pages padding (which are freed) the 56 * text section. Hence kernel identity mappings will be broken to smaller 57 * pages. For 64-bit, kernel text and kernel identity mappings are different, 58 * so we can enable protection checks as well as retain 2MB large page 59 * mappings for kernel text. 60 */ 61#define X86_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); 62 63#define X86_ALIGN_RODATA_END \ 64 . = ALIGN(HPAGE_SIZE); \ 65 __end_rodata_hpage_align = .; \ 66 __end_rodata_aligned = .; 67 68#define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE); 69#define ALIGN_ENTRY_TEXT_END . = ALIGN(PMD_SIZE); 70 71/* 72 * This section contains data which will be mapped as decrypted. Memory 73 * encryption operates on a page basis. Make this section PMD-aligned 74 * to avoid splitting the pages while mapping the section early. 75 * 76 * Note: We use a separate section so that only this section gets 77 * decrypted to avoid exposing more than we wish. 78 */ 79#define BSS_DECRYPTED \ 80 . = ALIGN(PMD_SIZE); \ 81 __start_bss_decrypted = .; \ 82 __pi___start_bss_decrypted = .; \ 83 *(.bss..decrypted); \ 84 . = ALIGN(PAGE_SIZE); \ 85 __start_bss_decrypted_unused = .; \ 86 . = ALIGN(PMD_SIZE); \ 87 __end_bss_decrypted = .; \ 88 __pi___end_bss_decrypted = .; \ 89 90#else 91 92#define X86_ALIGN_RODATA_BEGIN 93#define X86_ALIGN_RODATA_END \ 94 . = ALIGN(PAGE_SIZE); \ 95 __end_rodata_aligned = .; 96 97#define ALIGN_ENTRY_TEXT_BEGIN 98#define ALIGN_ENTRY_TEXT_END 99#define BSS_DECRYPTED 100 101#endif 102#if defined(CONFIG_X86_64) && defined(CONFIG_KEXEC_CORE) 103#define KEXEC_RELOCATE_KERNEL \ 104 . = ALIGN(0x100); \ 105 __relocate_kernel_start = .; \ 106 *(.text..relocate_kernel); \ 107 *(.data..relocate_kernel); \ 108 __relocate_kernel_end = .; 109 110ASSERT(__relocate_kernel_end - __relocate_kernel_start <= KEXEC_CONTROL_CODE_MAX_SIZE, 111 "relocate_kernel code too large!") 112#else 113#define KEXEC_RELOCATE_KERNEL 114#endif 115PHDRS { 116 text PT_LOAD FLAGS(5); /* R_E */ 117 data PT_LOAD FLAGS(6); /* RW_ */ 118 note PT_NOTE FLAGS(0); /* ___ */ 119} 120 121SECTIONS 122{ 123 . = __START_KERNEL; 124#ifdef CONFIG_X86_32 125 phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET); 126#else 127 phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET); 128#endif 129 130 /* Text and read-only data */ 131 .text : AT(ADDR(.text) - LOAD_OFFSET) { 132 _text = .; 133 __pi__text = .; 134 _stext = .; 135 ALIGN_ENTRY_TEXT_BEGIN 136 *(.text..__x86.rethunk_untrain) 137 ENTRY_TEXT 138 139#ifdef CONFIG_MITIGATION_SRSO 140 /* 141 * See the comment above srso_alias_untrain_ret()'s 142 * definition. 143 */ 144 . = srso_alias_untrain_ret | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20); 145 *(.text..__x86.rethunk_safe) 146#endif 147 ALIGN_ENTRY_TEXT_END 148 149 TEXT_TEXT 150 SCHED_TEXT 151 LOCK_TEXT 152 KPROBES_TEXT 153 SOFTIRQENTRY_TEXT 154#ifdef CONFIG_MITIGATION_RETPOLINE 155 *(.text..__x86.indirect_thunk) 156 *(.text..__x86.return_thunk) 157#endif 158 STATIC_CALL_TEXT 159 *(.gnu.warning) 160 161 } :text = 0xcccccccc 162 163 /* bootstrapping code */ 164 .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) { 165 HEAD_TEXT 166 } :text = 0xcccccccc 167 168 /* End of text section, which should occupy whole number of pages */ 169 _etext = .; 170 . = ALIGN(PAGE_SIZE); 171 172 X86_ALIGN_RODATA_BEGIN 173 RO_DATA(PAGE_SIZE) 174 X86_ALIGN_RODATA_END 175 176 /* Data */ 177 .data : AT(ADDR(.data) - LOAD_OFFSET) { 178 /* Start of data section */ 179 _sdata = .; 180 181 /* init_task */ 182 INIT_TASK_DATA(THREAD_SIZE) 183 184 /* equivalent to task_pt_regs(&init_task) */ 185 __top_init_kernel_stack = __end_init_stack - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE; 186 187#ifdef CONFIG_X86_32 188 /* 32 bit has nosave before _edata */ 189 NOSAVE_DATA 190#endif 191 192 PAGE_ALIGNED_DATA(PAGE_SIZE) 193 194 CACHE_HOT_DATA(L1_CACHE_BYTES) 195 196 CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) 197 198 DATA_DATA 199 CONSTRUCTORS 200 KEXEC_RELOCATE_KERNEL 201 202 /* rarely changed data like cpu maps */ 203 READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES) 204 205 /* End of data section */ 206 _edata = .; 207 } :data 208 209 BUG_TABLE 210 211 ORC_UNWIND_TABLE 212 213 /* Init code and data - will be freed after init */ 214 . = ALIGN(PAGE_SIZE); 215 .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { 216 __init_begin = .; /* paired with __init_end */ 217 } 218 219 INIT_TEXT_SECTION(PAGE_SIZE) 220 221 /* 222 * Section for code used exclusively before alternatives are run. All 223 * references to such code must be patched out by alternatives, normally 224 * by using X86_FEATURE_ALWAYS CPU feature bit. 225 * 226 * See static_cpu_has() for an example. 227 */ 228 .altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) { 229 *(.altinstr_aux) 230 . = ALIGN(PAGE_SIZE); 231 __inittext_end = .; 232 } 233 234 INIT_DATA_SECTION(16) 235 236 .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { 237 __x86_cpu_dev_start = .; 238 *(.x86_cpu_dev.init) 239 __x86_cpu_dev_end = .; 240 } 241 242#ifdef CONFIG_X86_INTEL_MID 243 .x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \ 244 LOAD_OFFSET) { 245 __x86_intel_mid_dev_start = .; 246 *(.x86_intel_mid_dev.init) 247 __x86_intel_mid_dev_end = .; 248 } 249#endif 250 251#ifdef CONFIG_MITIGATION_RETPOLINE 252 /* 253 * List of instructions that call/jmp/jcc to retpoline thunks 254 * __x86_indirect_thunk_*(). These instructions can be patched along 255 * with alternatives, after which the section can be freed. 256 */ 257 . = ALIGN(8); 258 .retpoline_sites : AT(ADDR(.retpoline_sites) - LOAD_OFFSET) { 259 __retpoline_sites = .; 260 *(.retpoline_sites) 261 __retpoline_sites_end = .; 262 } 263 264 . = ALIGN(8); 265 .return_sites : AT(ADDR(.return_sites) - LOAD_OFFSET) { 266 __return_sites = .; 267 *(.return_sites) 268 __return_sites_end = .; 269 } 270 271 . = ALIGN(8); 272 .call_sites : AT(ADDR(.call_sites) - LOAD_OFFSET) { 273 __call_sites = .; 274 *(.call_sites) 275 __call_sites_end = .; 276 } 277#endif 278 279#ifdef CONFIG_X86_KERNEL_IBT 280 . = ALIGN(8); 281 .ibt_endbr_seal : AT(ADDR(.ibt_endbr_seal) - LOAD_OFFSET) { 282 __ibt_endbr_seal = .; 283 *(.ibt_endbr_seal) 284 __ibt_endbr_seal_end = .; 285 } 286#endif 287 288#ifdef CONFIG_FINEIBT 289 . = ALIGN(8); 290 .cfi_sites : AT(ADDR(.cfi_sites) - LOAD_OFFSET) { 291 __cfi_sites = .; 292 *(.cfi_sites) 293 __cfi_sites_end = .; 294 } 295#endif 296 297 /* 298 * struct alt_inst entries. From the header (alternative.h): 299 * "Alternative instructions for different CPU types or capabilities" 300 * Think locking instructions on spinlocks. 301 */ 302 . = ALIGN(8); 303 .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { 304 __alt_instructions = .; 305 *(.altinstructions) 306 __alt_instructions_end = .; 307 } 308 309 /* 310 * And here are the replacement instructions. The linker sticks 311 * them as binary blobs. The .altinstructions has enough data to 312 * get the address and the length of them to patch the kernel safely. 313 */ 314 .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { 315 *(.altinstr_replacement) 316 } 317 318 . = ALIGN(8); 319 .apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) { 320 __apicdrivers = .; 321 *(.apicdrivers); 322 __apicdrivers_end = .; 323 } 324 325 . = ALIGN(8); 326 /* 327 * .exit.text is discarded at runtime, not link time, to deal with 328 * references from .altinstructions 329 */ 330 .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { 331 EXIT_TEXT 332 } 333 334 .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { 335 EXIT_DATA 336 } 337 338 PERCPU_SECTION(L1_CACHE_BYTES) 339 ASSERT(__per_cpu_hot_end - __per_cpu_hot_start <= 64, "percpu cache hot data too large") 340 341 RUNTIME_CONST_VARIABLES 342 RUNTIME_CONST(ptr, USER_PTR_MAX) 343 344 . = ALIGN(PAGE_SIZE); 345 346 /* freed after init ends here */ 347 .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { 348 __init_end = .; 349 } 350 351 /* 352 * smp_locks might be freed after init 353 * start/end must be page aligned 354 */ 355 . = ALIGN(PAGE_SIZE); 356 .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { 357 __smp_locks = .; 358 *(.smp_locks) 359 . = ALIGN(PAGE_SIZE); 360 __smp_locks_end = .; 361 } 362 363#ifdef CONFIG_X86_64 364 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { 365 NOSAVE_DATA 366 } 367#endif 368 369 /* BSS */ 370 . = ALIGN(PAGE_SIZE); 371 .bss : AT(ADDR(.bss) - LOAD_OFFSET) { 372 __bss_start = .; 373 *(.bss..page_aligned) 374 . = ALIGN(PAGE_SIZE); 375 *(BSS_MAIN) 376 BSS_DECRYPTED 377 . = ALIGN(PAGE_SIZE); 378 __bss_stop = .; 379 } 380 381 /* 382 * The memory occupied from _text to here, __end_of_kernel_reserve, is 383 * automatically reserved in setup_arch(). Anything after here must be 384 * explicitly reserved using memblock_reserve() or it will be discarded 385 * and treated as available memory. 386 */ 387 __end_of_kernel_reserve = .; 388 389 . = ALIGN(PAGE_SIZE); 390 .brk : AT(ADDR(.brk) - LOAD_OFFSET) { 391 __brk_base = .; 392 . += 64 * 1024; /* 64k alignment slop space */ 393 *(.bss..brk) /* areas brk users have reserved */ 394 __brk_limit = .; 395 } 396 397 . = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */ 398 _end = .; 399 __pi__end = .; 400 401#ifdef CONFIG_AMD_MEM_ENCRYPT 402 /* 403 * Early scratch/workarea section: Lives outside of the kernel proper 404 * (_text - _end). 405 * 406 * Resides after _end because even though the .brk section is after 407 * __end_of_kernel_reserve, the .brk section is later reserved as a 408 * part of the kernel. Since it is located after __end_of_kernel_reserve 409 * it will be discarded and become part of the available memory. As 410 * such, it can only be used by very early boot code and must not be 411 * needed afterwards. 412 * 413 * Currently used by SME for performing in-place encryption of the 414 * kernel during boot. Resides on a 2MB boundary to simplify the 415 * pagetable setup used for SME in-place encryption. 416 */ 417 . = ALIGN(HPAGE_SIZE); 418 .init.scratch : AT(ADDR(.init.scratch) - LOAD_OFFSET) { 419 __init_scratch_begin = .; 420 *(.init.scratch) 421 . = ALIGN(HPAGE_SIZE); 422 __init_scratch_end = .; 423 } 424#endif 425 426 STABS_DEBUG 427 DWARF_DEBUG 428#ifdef CONFIG_PROPELLER_CLANG 429 .llvm_bb_addr_map : { *(.llvm_bb_addr_map) } 430#endif 431 432 ELF_DETAILS 433 434 DISCARDS 435 436 /* 437 * Make sure that the .got.plt is either completely empty or it 438 * contains only the lazy dispatch entries. 439 */ 440 .got.plt (INFO) : { *(.got.plt) } 441 ASSERT(SIZEOF(.got.plt) == 0 || 442#ifdef CONFIG_X86_64 443 SIZEOF(.got.plt) == 0x18, 444#else 445 SIZEOF(.got.plt) == 0xc, 446#endif 447 "Unexpected GOT/PLT entries detected!") 448 449 /* 450 * Sections that should stay zero sized, which is safer to 451 * explicitly check instead of blindly discarding. 452 */ 453 .got : { 454 *(.got) *(.igot.*) 455 } 456 ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") 457 458 .plt : { 459 *(.plt) *(.plt.*) *(.iplt) 460 } 461 ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!") 462 463 .rel.dyn : { 464 *(.rel.*) *(.rel_*) 465 } 466 ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") 467 468 .rela.dyn : { 469 *(.rela.*) *(.rela_*) 470 } 471 ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") 472} 473 474/* 475 * COMPILE_TEST kernels can be large - CONFIG_KASAN, for example, can cause 476 * this. Let's assume that nobody will be running a COMPILE_TEST kernel and 477 * let's assert that fuller build coverage is more valuable than being able to 478 * run a COMPILE_TEST kernel. 479 */ 480#ifndef CONFIG_COMPILE_TEST 481/* 482 * The ASSERT() sync to . is intentional, for binutils 2.14 compatibility: 483 */ 484. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), 485 "kernel image bigger than KERNEL_IMAGE_SIZE"); 486#endif 487 488/* needed for Clang - see arch/x86/entry/entry.S */ 489PROVIDE(__ref_stack_chk_guard = __stack_chk_guard); 490 491#ifdef CONFIG_X86_64 492 493#ifdef CONFIG_MITIGATION_UNRET_ENTRY 494. = ASSERT((retbleed_return_thunk & 0x3f) == 0, "retbleed_return_thunk not cacheline-aligned"); 495#endif 496 497#ifdef CONFIG_MITIGATION_SRSO 498. = ASSERT((srso_safe_ret & 0x3f) == 0, "srso_safe_ret not cacheline-aligned"); 499/* 500 * GNU ld cannot do XOR until 2.41. 501 * https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f6f78318fca803c4907fb8d7f6ded8295f1947b1 502 * 503 * LLVM lld cannot do XOR until lld-17. 504 * https://github.com/llvm/llvm-project/commit/fae96104d4378166cbe5c875ef8ed808a356f3fb 505 * 506 * Instead do: (A | B) - (A & B) in order to compute the XOR 507 * of the two function addresses: 508 */ 509. = ASSERT(((ABSOLUTE(srso_alias_untrain_ret) | srso_alias_safe_ret) - 510 (ABSOLUTE(srso_alias_untrain_ret) & srso_alias_safe_ret)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)), 511 "SRSO function pair won't alias"); 512#endif 513 514#if defined(CONFIG_MITIGATION_ITS) && !defined(CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B) 515. = ASSERT(__x86_indirect_its_thunk_rax & 0x20, "__x86_indirect_thunk_rax not in second half of cacheline"); 516. = ASSERT(((__x86_indirect_its_thunk_rcx - __x86_indirect_its_thunk_rax) % 64) == 0, "Indirect thunks are not cacheline apart"); 517. = ASSERT(__x86_indirect_its_thunk_array == __x86_indirect_its_thunk_rax, "Gap in ITS thunk array"); 518#endif 519 520#if defined(CONFIG_MITIGATION_ITS) && !defined(CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B) 521. = ASSERT(its_return_thunk & 0x20, "its_return_thunk not in second half of cacheline"); 522#endif 523 524#endif /* CONFIG_X86_64 */ 525 526/* 527 * The symbols below are referenced using relative relocations in the 528 * respective ELF notes. This produces build time constants that the 529 * linker will never mark as relocatable. (Using just ABSOLUTE() is not 530 * sufficient for that). 531 */ 532#ifdef CONFIG_XEN_PV 533xen_elfnote_entry_value = 534 ABSOLUTE(xen_elfnote_entry) + ABSOLUTE(startup_xen); 535#endif 536#ifdef CONFIG_PVH 537xen_elfnote_phys32_entry_value = 538 ABSOLUTE(xen_elfnote_phys32_entry) + ABSOLUTE(pvh_start_xen - LOAD_OFFSET); 539#endif 540 541#include "../boot/startup/exports.h" 542