xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision 40970f7a) 
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 X86_ALIGN_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);
59
60#define X86_ALIGN_RODATA_END					\
61		. = ALIGN(HPAGE_SIZE);				\
62		__end_rodata_hpage_align = .;			\
63		__end_rodata_aligned = .;
64
65#define ALIGN_ENTRY_TEXT_BEGIN	. = ALIGN(PMD_SIZE);
66#define ALIGN_ENTRY_TEXT_END	. = ALIGN(PMD_SIZE);
67
68#else
69
70#define X86_ALIGN_RODATA_BEGIN
71#define X86_ALIGN_RODATA_END					\
72		. = ALIGN(PAGE_SIZE);				\
73		__end_rodata_aligned = .;
74
75#define ALIGN_ENTRY_TEXT_BEGIN
76#define ALIGN_ENTRY_TEXT_END
77
78#endif
79
80PHDRS {
81	text PT_LOAD FLAGS(5);          /* R_E */
82	data PT_LOAD FLAGS(6);          /* RW_ */
83#ifdef CONFIG_X86_64
84#ifdef CONFIG_SMP
85	percpu PT_LOAD FLAGS(6);        /* RW_ */
86#endif
87	init PT_LOAD FLAGS(7);          /* RWE */
88#endif
89	note PT_NOTE FLAGS(0);          /* ___ */
90}
91
92SECTIONS
93{
94#ifdef CONFIG_X86_32
95	. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
96	phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET);
97#else
98	. = __START_KERNEL;
99	phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET);
100#endif
101
102	/* Text and read-only data */
103	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
104		_text = .;
105		_stext = .;
106		/* bootstrapping code */
107		HEAD_TEXT
108		TEXT_TEXT
109		SCHED_TEXT
110		CPUIDLE_TEXT
111		LOCK_TEXT
112		KPROBES_TEXT
113		ALIGN_ENTRY_TEXT_BEGIN
114		ENTRY_TEXT
115		IRQENTRY_TEXT
116		ALIGN_ENTRY_TEXT_END
117		SOFTIRQENTRY_TEXT
118		*(.fixup)
119		*(.gnu.warning)
120
121#ifdef CONFIG_X86_64
122		. = ALIGN(PAGE_SIZE);
123		__entry_trampoline_start = .;
124		_entry_trampoline = .;
125		*(.entry_trampoline)
126		. = ALIGN(PAGE_SIZE);
127		__entry_trampoline_end = .;
128		ASSERT(. - _entry_trampoline == PAGE_SIZE, "entry trampoline is too big");
129#endif
130
131#ifdef CONFIG_RETPOLINE
132		__indirect_thunk_start = .;
133		*(.text.__x86.indirect_thunk)
134		__indirect_thunk_end = .;
135#endif
136
137		/* End of text section */
138		_etext = .;
139	} :text = 0x9090
140
141	NOTES :text :note
142
143	EXCEPTION_TABLE(16) :text = 0x9090
144
145	/* .text should occupy whole number of pages */
146	. = ALIGN(PAGE_SIZE);
147	X86_ALIGN_RODATA_BEGIN
148	RO_DATA(PAGE_SIZE)
149	X86_ALIGN_RODATA_END
150
151	/* Data */
152	.data : AT(ADDR(.data) - LOAD_OFFSET) {
153		/* Start of data section */
154		_sdata = .;
155
156		/* init_task */
157		INIT_TASK_DATA(THREAD_SIZE)
158
159#ifdef CONFIG_X86_32
160		/* 32 bit has nosave before _edata */
161		NOSAVE_DATA
162#endif
163
164		PAGE_ALIGNED_DATA(PAGE_SIZE)
165
166		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
167
168		DATA_DATA
169		CONSTRUCTORS
170
171		/* rarely changed data like cpu maps */
172		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
173
174		/* End of data section */
175		_edata = .;
176	} :data
177
178	BUG_TABLE
179
180	ORC_UNWIND_TABLE
181
182	. = ALIGN(PAGE_SIZE);
183	__vvar_page = .;
184
185	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
186		/* work around gold bug 13023 */
187		__vvar_beginning_hack = .;
188
189		/* Place all vvars at the offsets in asm/vvar.h. */
190#define EMIT_VVAR(name, offset) 			\
191		. = __vvar_beginning_hack + offset;	\
192		*(.vvar_ ## name)
193#define __VVAR_KERNEL_LDS
194#include <asm/vvar.h>
195#undef __VVAR_KERNEL_LDS
196#undef EMIT_VVAR
197
198		/*
199		 * Pad the rest of the page with zeros.  Otherwise the loader
200		 * can leave garbage here.
201		 */
202		. = __vvar_beginning_hack + PAGE_SIZE;
203	} :data
204
205	. = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
206
207	/* Init code and data - will be freed after init */
208	. = ALIGN(PAGE_SIZE);
209	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
210		__init_begin = .; /* paired with __init_end */
211	}
212
213#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
214	/*
215	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
216	 * output PHDR, so the next output section - .init.text - should
217	 * start another segment - init.
218	 */
219	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
220	ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START,
221	       "per-CPU data too large - increase CONFIG_PHYSICAL_START")
222#endif
223
224	INIT_TEXT_SECTION(PAGE_SIZE)
225#ifdef CONFIG_X86_64
226	:init
227#endif
228
229	/*
230	 * Section for code used exclusively before alternatives are run. All
231	 * references to such code must be patched out by alternatives, normally
232	 * by using X86_FEATURE_ALWAYS CPU feature bit.
233	 *
234	 * See static_cpu_has() for an example.
235	 */
236	.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
237		*(.altinstr_aux)
238	}
239
240	INIT_DATA_SECTION(16)
241
242	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
243		__x86_cpu_dev_start = .;
244		*(.x86_cpu_dev.init)
245		__x86_cpu_dev_end = .;
246	}
247
248#ifdef CONFIG_X86_INTEL_MID
249	.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
250								LOAD_OFFSET) {
251		__x86_intel_mid_dev_start = .;
252		*(.x86_intel_mid_dev.init)
253		__x86_intel_mid_dev_end = .;
254	}
255#endif
256
257	/*
258	 * start address and size of operations which during runtime
259	 * can be patched with virtualization friendly instructions or
260	 * baremetal native ones. Think page table operations.
261	 * Details in paravirt_types.h
262	 */
263	. = ALIGN(8);
264	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
265		__parainstructions = .;
266		*(.parainstructions)
267		__parainstructions_end = .;
268	}
269
270	/*
271	 * struct alt_inst entries. From the header (alternative.h):
272	 * "Alternative instructions for different CPU types or capabilities"
273	 * Think locking instructions on spinlocks.
274	 */
275	. = ALIGN(8);
276	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
277		__alt_instructions = .;
278		*(.altinstructions)
279		__alt_instructions_end = .;
280	}
281
282	/*
283	 * And here are the replacement instructions. The linker sticks
284	 * them as binary blobs. The .altinstructions has enough data to
285	 * get the address and the length of them to patch the kernel safely.
286	 */
287	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
288		*(.altinstr_replacement)
289	}
290
291	/*
292	 * struct iommu_table_entry entries are injected in this section.
293	 * It is an array of IOMMUs which during run time gets sorted depending
294	 * on its dependency order. After rootfs_initcall is complete
295	 * this section can be safely removed.
296	 */
297	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
298		__iommu_table = .;
299		*(.iommu_table)
300		__iommu_table_end = .;
301	}
302
303	. = ALIGN(8);
304	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
305		__apicdrivers = .;
306		*(.apicdrivers);
307		__apicdrivers_end = .;
308	}
309
310	. = ALIGN(8);
311	/*
312	 * .exit.text is discard at runtime, not link time, to deal with
313	 *  references from .altinstructions and .eh_frame
314	 */
315	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
316		EXIT_TEXT
317	}
318
319	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
320		EXIT_DATA
321	}
322
323#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
324	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
325#endif
326
327	. = ALIGN(PAGE_SIZE);
328
329	/* freed after init ends here */
330	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
331		__init_end = .;
332	}
333
334	/*
335	 * smp_locks might be freed after init
336	 * start/end must be page aligned
337	 */
338	. = ALIGN(PAGE_SIZE);
339	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
340		__smp_locks = .;
341		*(.smp_locks)
342		. = ALIGN(PAGE_SIZE);
343		__smp_locks_end = .;
344	}
345
346#ifdef CONFIG_X86_64
347	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
348		NOSAVE_DATA
349	}
350#endif
351
352	/* BSS */
353	. = ALIGN(PAGE_SIZE);
354	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
355		__bss_start = .;
356		*(.bss..page_aligned)
357		*(.bss)
358		. = ALIGN(PAGE_SIZE);
359		__bss_stop = .;
360	}
361
362	. = ALIGN(PAGE_SIZE);
363	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
364		__brk_base = .;
365		. += 64 * 1024;		/* 64k alignment slop space */
366		*(.brk_reservation)	/* areas brk users have reserved */
367		__brk_limit = .;
368	}
369
370	. = ALIGN(PAGE_SIZE);		/* keep VO_INIT_SIZE page aligned */
371	_end = .;
372
373	STABS_DEBUG
374	DWARF_DEBUG
375
376	/* Sections to be discarded */
377	DISCARDS
378	/DISCARD/ : {
379		*(.eh_frame)
380	}
381}
382
383
384#ifdef CONFIG_X86_32
385/*
386 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
387 */
388. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
389	   "kernel image bigger than KERNEL_IMAGE_SIZE");
390#else
391/*
392 * Per-cpu symbols which need to be offset from __per_cpu_load
393 * for the boot processor.
394 */
395#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
396INIT_PER_CPU(gdt_page);
397INIT_PER_CPU(irq_stack_union);
398
399/*
400 * Build-time check on the image size:
401 */
402. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
403	   "kernel image bigger than KERNEL_IMAGE_SIZE");
404
405#ifdef CONFIG_SMP
406. = ASSERT((irq_stack_union == 0),
407           "irq_stack_union is not at start of per-cpu area");
408#endif
409
410#endif /* CONFIG_X86_32 */
411
412#ifdef CONFIG_KEXEC_CORE
413#include <asm/kexec.h>
414
415. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
416           "kexec control code size is too big");
417#endif
418
419