xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision e3b9f1e8) 
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#ifdef CONFIG_X86_32
19#define LOAD_OFFSET __PAGE_OFFSET
20#else
21#define LOAD_OFFSET __START_KERNEL_map
22#endif
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
32#undef i386     /* in case the preprocessor is a 32bit one */
33
34OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT)
35
36#ifdef CONFIG_X86_32
37OUTPUT_ARCH(i386)
38ENTRY(phys_startup_32)
39jiffies = jiffies_64;
40#else
41OUTPUT_ARCH(i386:x86-64)
42ENTRY(phys_startup_64)
43jiffies_64 = jiffies;
44#endif
45
46#if defined(CONFIG_X86_64)
47/*
48 * On 64-bit, align RODATA to 2MB so we retain large page mappings for
49 * boundaries spanning kernel text, rodata and data sections.
50 *
51 * However, kernel identity mappings will have different RWX permissions
52 * to the pages mapping to text and to the pages padding (which are freed) the
53 * text section. Hence kernel identity mappings will be broken to smaller
54 * pages. For 64-bit, kernel text and kernel identity mappings are different,
55 * so we can enable protection checks as well as retain 2MB large page
56 * mappings for kernel text.
57 */
58#define X64_ALIGN_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);
59
60#define X64_ALIGN_RODATA_END					\
61		. = ALIGN(HPAGE_SIZE);				\
62		__end_rodata_hpage_align = .;
63
64#define ALIGN_ENTRY_TEXT_BEGIN	. = ALIGN(PMD_SIZE);
65#define ALIGN_ENTRY_TEXT_END	. = ALIGN(PMD_SIZE);
66
67#else
68
69#define X64_ALIGN_RODATA_BEGIN
70#define X64_ALIGN_RODATA_END
71
72#define ALIGN_ENTRY_TEXT_BEGIN
73#define ALIGN_ENTRY_TEXT_END
74
75#endif
76
77PHDRS {
78	text PT_LOAD FLAGS(5);          /* R_E */
79	data PT_LOAD FLAGS(6);          /* RW_ */
80#ifdef CONFIG_X86_64
81#ifdef CONFIG_SMP
82	percpu PT_LOAD FLAGS(6);        /* RW_ */
83#endif
84	init PT_LOAD FLAGS(7);          /* RWE */
85#endif
86	note PT_NOTE FLAGS(0);          /* ___ */
87}
88
89SECTIONS
90{
91#ifdef CONFIG_X86_32
92	. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
93	phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET);
94#else
95	. = __START_KERNEL;
96	phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET);
97#endif
98
99	/* Text and read-only data */
100	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
101		_text = .;
102		_stext = .;
103		/* bootstrapping code */
104		HEAD_TEXT
105		. = ALIGN(8);
106		TEXT_TEXT
107		SCHED_TEXT
108		CPUIDLE_TEXT
109		LOCK_TEXT
110		KPROBES_TEXT
111		ALIGN_ENTRY_TEXT_BEGIN
112		ENTRY_TEXT
113		IRQENTRY_TEXT
114		ALIGN_ENTRY_TEXT_END
115		SOFTIRQENTRY_TEXT
116		*(.fixup)
117		*(.gnu.warning)
118
119#ifdef CONFIG_X86_64
120		. = ALIGN(PAGE_SIZE);
121		_entry_trampoline = .;
122		*(.entry_trampoline)
123		. = ALIGN(PAGE_SIZE);
124		ASSERT(. - _entry_trampoline == PAGE_SIZE, "entry trampoline is too big");
125#endif
126
127#ifdef CONFIG_RETPOLINE
128		__indirect_thunk_start = .;
129		*(.text.__x86.indirect_thunk)
130		__indirect_thunk_end = .;
131#endif
132
133		/* End of text section */
134		_etext = .;
135	} :text = 0x9090
136
137	NOTES :text :note
138
139	EXCEPTION_TABLE(16) :text = 0x9090
140
141	/* .text should occupy whole number of pages */
142	. = ALIGN(PAGE_SIZE);
143	X64_ALIGN_RODATA_BEGIN
144	RO_DATA(PAGE_SIZE)
145	X64_ALIGN_RODATA_END
146
147	/* Data */
148	.data : AT(ADDR(.data) - LOAD_OFFSET) {
149		/* Start of data section */
150		_sdata = .;
151
152		/* init_task */
153		INIT_TASK_DATA(THREAD_SIZE)
154
155#ifdef CONFIG_X86_32
156		/* 32 bit has nosave before _edata */
157		NOSAVE_DATA
158#endif
159
160		PAGE_ALIGNED_DATA(PAGE_SIZE)
161
162		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
163
164		DATA_DATA
165		CONSTRUCTORS
166
167		/* rarely changed data like cpu maps */
168		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
169
170		/* End of data section */
171		_edata = .;
172	} :data
173
174	BUG_TABLE
175
176	ORC_UNWIND_TABLE
177
178	. = ALIGN(PAGE_SIZE);
179	__vvar_page = .;
180
181	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
182		/* work around gold bug 13023 */
183		__vvar_beginning_hack = .;
184
185		/* Place all vvars at the offsets in asm/vvar.h. */
186#define EMIT_VVAR(name, offset) 			\
187		. = __vvar_beginning_hack + offset;	\
188		*(.vvar_ ## name)
189#define __VVAR_KERNEL_LDS
190#include <asm/vvar.h>
191#undef __VVAR_KERNEL_LDS
192#undef EMIT_VVAR
193
194		/*
195		 * Pad the rest of the page with zeros.  Otherwise the loader
196		 * can leave garbage here.
197		 */
198		. = __vvar_beginning_hack + PAGE_SIZE;
199	} :data
200
201       . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
202
203	/* Init code and data - will be freed after init */
204	. = ALIGN(PAGE_SIZE);
205	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
206		__init_begin = .; /* paired with __init_end */
207	}
208
209#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
210	/*
211	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
212	 * output PHDR, so the next output section - .init.text - should
213	 * start another segment - init.
214	 */
215	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
216	ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START,
217	       "per-CPU data too large - increase CONFIG_PHYSICAL_START")
218#endif
219
220	INIT_TEXT_SECTION(PAGE_SIZE)
221#ifdef CONFIG_X86_64
222	:init
223#endif
224
225	/*
226	 * Section for code used exclusively before alternatives are run. All
227	 * references to such code must be patched out by alternatives, normally
228	 * by using X86_FEATURE_ALWAYS CPU feature bit.
229	 *
230	 * See static_cpu_has() for an example.
231	 */
232	.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
233		*(.altinstr_aux)
234	}
235
236	INIT_DATA_SECTION(16)
237
238	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
239		__x86_cpu_dev_start = .;
240		*(.x86_cpu_dev.init)
241		__x86_cpu_dev_end = .;
242	}
243
244#ifdef CONFIG_X86_INTEL_MID
245	.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
246								LOAD_OFFSET) {
247		__x86_intel_mid_dev_start = .;
248		*(.x86_intel_mid_dev.init)
249		__x86_intel_mid_dev_end = .;
250	}
251#endif
252
253	/*
254	 * start address and size of operations which during runtime
255	 * can be patched with virtualization friendly instructions or
256	 * baremetal native ones. Think page table operations.
257	 * Details in paravirt_types.h
258	 */
259	. = ALIGN(8);
260	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
261		__parainstructions = .;
262		*(.parainstructions)
263		__parainstructions_end = .;
264	}
265
266	/*
267	 * struct alt_inst entries. From the header (alternative.h):
268	 * "Alternative instructions for different CPU types or capabilities"
269	 * Think locking instructions on spinlocks.
270	 */
271	. = ALIGN(8);
272	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
273		__alt_instructions = .;
274		*(.altinstructions)
275		__alt_instructions_end = .;
276	}
277
278	/*
279	 * And here are the replacement instructions. The linker sticks
280	 * them as binary blobs. The .altinstructions has enough data to
281	 * get the address and the length of them to patch the kernel safely.
282	 */
283	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
284		*(.altinstr_replacement)
285	}
286
287	/*
288	 * struct iommu_table_entry entries are injected in this section.
289	 * It is an array of IOMMUs which during run time gets sorted depending
290	 * on its dependency order. After rootfs_initcall is complete
291	 * this section can be safely removed.
292	 */
293	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
294		__iommu_table = .;
295		*(.iommu_table)
296		__iommu_table_end = .;
297	}
298
299	. = ALIGN(8);
300	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
301		__apicdrivers = .;
302		*(.apicdrivers);
303		__apicdrivers_end = .;
304	}
305
306	. = ALIGN(8);
307	/*
308	 * .exit.text is discard at runtime, not link time, to deal with
309	 *  references from .altinstructions and .eh_frame
310	 */
311	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
312		EXIT_TEXT
313	}
314
315	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
316		EXIT_DATA
317	}
318
319#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
320	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
321#endif
322
323	. = ALIGN(PAGE_SIZE);
324
325	/* freed after init ends here */
326	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
327		__init_end = .;
328	}
329
330	/*
331	 * smp_locks might be freed after init
332	 * start/end must be page aligned
333	 */
334	. = ALIGN(PAGE_SIZE);
335	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
336		__smp_locks = .;
337		*(.smp_locks)
338		. = ALIGN(PAGE_SIZE);
339		__smp_locks_end = .;
340	}
341
342#ifdef CONFIG_X86_64
343	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
344		NOSAVE_DATA
345	}
346#endif
347
348	/* BSS */
349	. = ALIGN(PAGE_SIZE);
350	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
351		__bss_start = .;
352		*(.bss..page_aligned)
353		*(.bss)
354		. = ALIGN(PAGE_SIZE);
355		__bss_stop = .;
356	}
357
358	. = ALIGN(PAGE_SIZE);
359	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
360		__brk_base = .;
361		. += 64 * 1024;		/* 64k alignment slop space */
362		*(.brk_reservation)	/* areas brk users have reserved */
363		__brk_limit = .;
364	}
365
366	. = ALIGN(PAGE_SIZE);		/* keep VO_INIT_SIZE page aligned */
367	_end = .;
368
369        STABS_DEBUG
370        DWARF_DEBUG
371
372	/* Sections to be discarded */
373	DISCARDS
374	/DISCARD/ : {
375		*(.eh_frame)
376	}
377}
378
379
380#ifdef CONFIG_X86_32
381/*
382 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
383 */
384. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
385	   "kernel image bigger than KERNEL_IMAGE_SIZE");
386#else
387/*
388 * Per-cpu symbols which need to be offset from __per_cpu_load
389 * for the boot processor.
390 */
391#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
392INIT_PER_CPU(gdt_page);
393INIT_PER_CPU(irq_stack_union);
394
395/*
396 * Build-time check on the image size:
397 */
398. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
399	   "kernel image bigger than KERNEL_IMAGE_SIZE");
400
401#ifdef CONFIG_SMP
402. = ASSERT((irq_stack_union == 0),
403           "irq_stack_union is not at start of per-cpu area");
404#endif
405
406#endif /* CONFIG_X86_32 */
407
408#ifdef CONFIG_KEXEC_CORE
409#include <asm/kexec.h>
410
411. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
412           "kexec control code size is too big");
413#endif
414
415