xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision cfdfc14e) 
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		TEXT_TEXT
106		SCHED_TEXT
107		CPUIDLE_TEXT
108		LOCK_TEXT
109		KPROBES_TEXT
110		ALIGN_ENTRY_TEXT_BEGIN
111		ENTRY_TEXT
112		IRQENTRY_TEXT
113		ALIGN_ENTRY_TEXT_END
114		SOFTIRQENTRY_TEXT
115		*(.fixup)
116		*(.gnu.warning)
117
118#ifdef CONFIG_X86_64
119		. = ALIGN(PAGE_SIZE);
120		__entry_trampoline_start = .;
121		_entry_trampoline = .;
122		*(.entry_trampoline)
123		. = ALIGN(PAGE_SIZE);
124		__entry_trampoline_end = .;
125		ASSERT(. - _entry_trampoline == PAGE_SIZE, "entry trampoline is too big");
126#endif
127
128#ifdef CONFIG_RETPOLINE
129		__indirect_thunk_start = .;
130		*(.text.__x86.indirect_thunk)
131		__indirect_thunk_end = .;
132#endif
133
134		/* End of text section */
135		_etext = .;
136	} :text = 0x9090
137
138	NOTES :text :note
139
140	EXCEPTION_TABLE(16) :text = 0x9090
141
142	/* .text should occupy whole number of pages */
143	. = ALIGN(PAGE_SIZE);
144	X64_ALIGN_RODATA_BEGIN
145	RO_DATA(PAGE_SIZE)
146	X64_ALIGN_RODATA_END
147
148	/* Data */
149	.data : AT(ADDR(.data) - LOAD_OFFSET) {
150		/* Start of data section */
151		_sdata = .;
152
153		/* init_task */
154		INIT_TASK_DATA(THREAD_SIZE)
155
156#ifdef CONFIG_X86_32
157		/* 32 bit has nosave before _edata */
158		NOSAVE_DATA
159#endif
160
161		PAGE_ALIGNED_DATA(PAGE_SIZE)
162
163		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
164
165		DATA_DATA
166		CONSTRUCTORS
167
168		/* rarely changed data like cpu maps */
169		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
170
171		/* End of data section */
172		_edata = .;
173	} :data
174
175	BUG_TABLE
176
177	ORC_UNWIND_TABLE
178
179	. = ALIGN(PAGE_SIZE);
180	__vvar_page = .;
181
182	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
183		/* work around gold bug 13023 */
184		__vvar_beginning_hack = .;
185
186		/* Place all vvars at the offsets in asm/vvar.h. */
187#define EMIT_VVAR(name, offset) 			\
188		. = __vvar_beginning_hack + offset;	\
189		*(.vvar_ ## name)
190#define __VVAR_KERNEL_LDS
191#include <asm/vvar.h>
192#undef __VVAR_KERNEL_LDS
193#undef EMIT_VVAR
194
195		/*
196		 * Pad the rest of the page with zeros.  Otherwise the loader
197		 * can leave garbage here.
198		 */
199		. = __vvar_beginning_hack + PAGE_SIZE;
200	} :data
201
202	. = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
203
204	/* Init code and data - will be freed after init */
205	. = ALIGN(PAGE_SIZE);
206	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
207		__init_begin = .; /* paired with __init_end */
208	}
209
210#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
211	/*
212	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
213	 * output PHDR, so the next output section - .init.text - should
214	 * start another segment - init.
215	 */
216	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
217	ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START,
218	       "per-CPU data too large - increase CONFIG_PHYSICAL_START")
219#endif
220
221	INIT_TEXT_SECTION(PAGE_SIZE)
222#ifdef CONFIG_X86_64
223	:init
224#endif
225
226	/*
227	 * Section for code used exclusively before alternatives are run. All
228	 * references to such code must be patched out by alternatives, normally
229	 * by using X86_FEATURE_ALWAYS CPU feature bit.
230	 *
231	 * See static_cpu_has() for an example.
232	 */
233	.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
234		*(.altinstr_aux)
235	}
236
237	INIT_DATA_SECTION(16)
238
239	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
240		__x86_cpu_dev_start = .;
241		*(.x86_cpu_dev.init)
242		__x86_cpu_dev_end = .;
243	}
244
245#ifdef CONFIG_X86_INTEL_MID
246	.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
247								LOAD_OFFSET) {
248		__x86_intel_mid_dev_start = .;
249		*(.x86_intel_mid_dev.init)
250		__x86_intel_mid_dev_end = .;
251	}
252#endif
253
254	/*
255	 * start address and size of operations which during runtime
256	 * can be patched with virtualization friendly instructions or
257	 * baremetal native ones. Think page table operations.
258	 * Details in paravirt_types.h
259	 */
260	. = ALIGN(8);
261	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
262		__parainstructions = .;
263		*(.parainstructions)
264		__parainstructions_end = .;
265	}
266
267	/*
268	 * struct alt_inst entries. From the header (alternative.h):
269	 * "Alternative instructions for different CPU types or capabilities"
270	 * Think locking instructions on spinlocks.
271	 */
272	. = ALIGN(8);
273	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
274		__alt_instructions = .;
275		*(.altinstructions)
276		__alt_instructions_end = .;
277	}
278
279	/*
280	 * And here are the replacement instructions. The linker sticks
281	 * them as binary blobs. The .altinstructions has enough data to
282	 * get the address and the length of them to patch the kernel safely.
283	 */
284	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
285		*(.altinstr_replacement)
286	}
287
288	/*
289	 * struct iommu_table_entry entries are injected in this section.
290	 * It is an array of IOMMUs which during run time gets sorted depending
291	 * on its dependency order. After rootfs_initcall is complete
292	 * this section can be safely removed.
293	 */
294	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
295		__iommu_table = .;
296		*(.iommu_table)
297		__iommu_table_end = .;
298	}
299
300	. = ALIGN(8);
301	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
302		__apicdrivers = .;
303		*(.apicdrivers);
304		__apicdrivers_end = .;
305	}
306
307	. = ALIGN(8);
308	/*
309	 * .exit.text is discard at runtime, not link time, to deal with
310	 *  references from .altinstructions and .eh_frame
311	 */
312	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
313		EXIT_TEXT
314	}
315
316	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
317		EXIT_DATA
318	}
319
320#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
321	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
322#endif
323
324	. = ALIGN(PAGE_SIZE);
325
326	/* freed after init ends here */
327	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
328		__init_end = .;
329	}
330
331	/*
332	 * smp_locks might be freed after init
333	 * start/end must be page aligned
334	 */
335	. = ALIGN(PAGE_SIZE);
336	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
337		__smp_locks = .;
338		*(.smp_locks)
339		. = ALIGN(PAGE_SIZE);
340		__smp_locks_end = .;
341	}
342
343#ifdef CONFIG_X86_64
344	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
345		NOSAVE_DATA
346	}
347#endif
348
349	/* BSS */
350	. = ALIGN(PAGE_SIZE);
351	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
352		__bss_start = .;
353		*(.bss..page_aligned)
354		*(.bss)
355		. = ALIGN(PAGE_SIZE);
356		__bss_stop = .;
357	}
358
359	. = ALIGN(PAGE_SIZE);
360	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
361		__brk_base = .;
362		. += 64 * 1024;		/* 64k alignment slop space */
363		*(.brk_reservation)	/* areas brk users have reserved */
364		__brk_limit = .;
365	}
366
367	. = ALIGN(PAGE_SIZE);		/* keep VO_INIT_SIZE page aligned */
368	_end = .;
369
370	STABS_DEBUG
371	DWARF_DEBUG
372
373	/* Sections to be discarded */
374	DISCARDS
375	/DISCARD/ : {
376		*(.eh_frame)
377	}
378}
379
380
381#ifdef CONFIG_X86_32
382/*
383 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
384 */
385. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
386	   "kernel image bigger than KERNEL_IMAGE_SIZE");
387#else
388/*
389 * Per-cpu symbols which need to be offset from __per_cpu_load
390 * for the boot processor.
391 */
392#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
393INIT_PER_CPU(gdt_page);
394INIT_PER_CPU(irq_stack_union);
395
396/*
397 * Build-time check on the image size:
398 */
399. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
400	   "kernel image bigger than KERNEL_IMAGE_SIZE");
401
402#ifdef CONFIG_SMP
403. = ASSERT((irq_stack_union == 0),
404           "irq_stack_union is not at start of per-cpu area");
405#endif
406
407#endif /* CONFIG_X86_32 */
408
409#ifdef CONFIG_KEXEC_CORE
410#include <asm/kexec.h>
411
412. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
413           "kexec control code size is too big");
414#endif
415
416