summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/vmlinux.lds.S
blob: 49edf2dd3613e7b7dcf5a9dc98b7a7cd84fd52f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
/*
 * ld script for the x86 kernel
 *
 * Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 *
 * Modernisation, unification and other changes and fixes:
 *   Copyright (C) 2007-2009  Sam Ravnborg <sam@ravnborg.org>
 *
 *
 * Don't define absolute symbols until and unless you know that symbol
 * value is should remain constant even if kernel image is relocated
 * at run time. Absolute symbols are not relocated. If symbol value should
 * change if kernel is relocated, make the symbol section relative and
 * put it inside the section definition.
 */

#ifdef CONFIG_X86_32
#define LOAD_OFFSET __PAGE_OFFSET
#else
#define LOAD_OFFSET __START_KERNEL_map
#endif

#include <asm-generic/vmlinux.lds.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page_types.h>
#include <asm/cache.h>
#include <asm/boot.h>

#undef i386     /* in case the preprocessor is a 32bit one */

OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT)

#ifdef CONFIG_X86_32
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
jiffies = jiffies_64;
#else
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
#endif

#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
/*
 * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA
 * we retain large page mappings for boundaries spanning kernel text, rodata
 * and data sections.
 *
 * However, kernel identity mappings will have different RWX permissions
 * to the pages mapping to text and to the pages padding (which are freed) the
 * text section. Hence kernel identity mappings will be broken to smaller
 * pages. For 64-bit, kernel text and kernel identity mappings are different,
 * so we can enable protection checks that come with CONFIG_DEBUG_RODATA,
 * as well as retain 2MB large page mappings for kernel text.
 */
#define X64_ALIGN_DEBUG_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);

#define X64_ALIGN_DEBUG_RODATA_END				\
		. = ALIGN(HPAGE_SIZE);				\
		__end_rodata_hpage_align = .;

#else

#define X64_ALIGN_DEBUG_RODATA_BEGIN
#define X64_ALIGN_DEBUG_RODATA_END

#endif

PHDRS {
	text PT_LOAD FLAGS(5);          /* R_E */
	data PT_LOAD FLAGS(6);          /* RW_ */
#ifdef CONFIG_X86_64
#ifdef CONFIG_SMP
	percpu PT_LOAD FLAGS(6);        /* RW_ */
#endif
	init PT_LOAD FLAGS(7);          /* RWE */
#endif
	note PT_NOTE FLAGS(0);          /* ___ */
}

SECTIONS
{
#ifdef CONFIG_X86_32
        . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
        phys_startup_32 = startup_32 - LOAD_OFFSET;
#else
        . = __START_KERNEL;
        phys_startup_64 = startup_64 - LOAD_OFFSET;
#endif

	/* Text and read-only data */
	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
		_text = .;
		/* bootstrapping code */
		HEAD_TEXT
		. = ALIGN(8);
		_stext = .;
		TEXT_TEXT
		SCHED_TEXT
		LOCK_TEXT
		KPROBES_TEXT
		ENTRY_TEXT
		IRQENTRY_TEXT
		*(.fixup)
		*(.gnu.warning)
		/* End of text section */
		_etext = .;
	} :text = 0x9090

	NOTES :text :note

	EXCEPTION_TABLE(16) :text = 0x9090

#if defined(CONFIG_DEBUG_RODATA)
	/* .text should occupy whole number of pages */
	. = ALIGN(PAGE_SIZE);
#endif
	X64_ALIGN_DEBUG_RODATA_BEGIN
	RO_DATA(PAGE_SIZE)
	X64_ALIGN_DEBUG_RODATA_END

	/* Data */
	.data : AT(ADDR(.data) - LOAD_OFFSET) {
		/* Start of data section */
		_sdata = .;

		/* init_task */
		INIT_TASK_DATA(THREAD_SIZE)

#ifdef CONFIG_X86_32
		/* 32 bit has nosave before _edata */
		NOSAVE_DATA
#endif

		PAGE_ALIGNED_DATA(PAGE_SIZE)

		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)

		DATA_DATA
		CONSTRUCTORS

		/* rarely changed data like cpu maps */
		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)

		/* End of data section */
		_edata = .;
	} :data


	. = ALIGN(PAGE_SIZE);
	__vvar_page = .;

	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
		/* work around gold bug 13023 */
		__vvar_beginning_hack = .;

		/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) 			\
		. = __vvar_beginning_hack + offset;	\
		*(.vvar_ ## name)
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR

		/*
		 * Pad the rest of the page with zeros.  Otherwise the loader
		 * can leave garbage here.
		 */
		. = __vvar_beginning_hack + PAGE_SIZE;
	} :data

       . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);

	/* Init code and data - will be freed after init */
	. = ALIGN(PAGE_SIZE);
	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
		__init_begin = .; /* paired with __init_end */
	}

#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
	/*
	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
	 * output PHDR, so the next output section - .init.text - should
	 * start another segment - init.
	 */
	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
#endif

	INIT_TEXT_SECTION(PAGE_SIZE)
#ifdef CONFIG_X86_64
	:init
#endif

	INIT_DATA_SECTION(16)

	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
		__x86_cpu_dev_start = .;
		*(.x86_cpu_dev.init)
		__x86_cpu_dev_end = .;
	}

#ifdef CONFIG_X86_INTEL_MID
	.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
								LOAD_OFFSET) {
		__x86_intel_mid_dev_start = .;
		*(.x86_intel_mid_dev.init)
		__x86_intel_mid_dev_end = .;
	}
#endif

	/*
	 * start address and size of operations which during runtime
	 * can be patched with virtualization friendly instructions or
	 * baremetal native ones. Think page table operations.
	 * Details in paravirt_types.h
	 */
	. = ALIGN(8);
	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
		__parainstructions = .;
		*(.parainstructions)
		__parainstructions_end = .;
	}

	/*
	 * struct alt_inst entries. From the header (alternative.h):
	 * "Alternative instructions for different CPU types or capabilities"
	 * Think locking instructions on spinlocks.
	 */
	. = ALIGN(8);
	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
		__alt_instructions = .;
		*(.altinstructions)
		__alt_instructions_end = .;
	}

	/*
	 * And here are the replacement instructions. The linker sticks
	 * them as binary blobs. The .altinstructions has enough data to
	 * get the address and the length of them to patch the kernel safely.
	 */
	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
		*(.altinstr_replacement)
	}

	/*
	 * struct iommu_table_entry entries are injected in this section.
	 * It is an array of IOMMUs which during run time gets sorted depending
	 * on its dependency order. After rootfs_initcall is complete
	 * this section can be safely removed.
	 */
	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
		__iommu_table = .;
		*(.iommu_table)
		__iommu_table_end = .;
	}

	. = ALIGN(8);
	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
		__apicdrivers = .;
		*(.apicdrivers);
		__apicdrivers_end = .;
	}

	. = ALIGN(8);
	/*
	 * .exit.text is discard at runtime, not link time, to deal with
	 *  references from .altinstructions and .eh_frame
	 */
	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
		EXIT_TEXT
	}

	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
		EXIT_DATA
	}

#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
#endif

	. = ALIGN(PAGE_SIZE);

	/* freed after init ends here */
	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
		__init_end = .;
	}

	/*
	 * smp_locks might be freed after init
	 * start/end must be page aligned
	 */
	. = ALIGN(PAGE_SIZE);
	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
		__smp_locks = .;
		*(.smp_locks)
		. = ALIGN(PAGE_SIZE);
		__smp_locks_end = .;
	}

#ifdef CONFIG_X86_64
	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
		NOSAVE_DATA
	}
#endif

	/* BSS */
	. = ALIGN(PAGE_SIZE);
	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
		__bss_start = .;
		*(.bss..page_aligned)
		*(.bss)
		. = ALIGN(PAGE_SIZE);
		__bss_stop = .;
	}

	. = ALIGN(PAGE_SIZE);
	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
		__brk_base = .;
		. += 64 * 1024;		/* 64k alignment slop space */
		*(.brk_reservation)	/* areas brk users have reserved */
		__brk_limit = .;
	}

	_end = .;

        STABS_DEBUG
        DWARF_DEBUG

	/* Sections to be discarded */
	DISCARDS
	/DISCARD/ : { *(.eh_frame) }
}


#ifdef CONFIG_X86_32
/*
 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
 */
. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
	   "kernel image bigger than KERNEL_IMAGE_SIZE");
#else
/*
 * Per-cpu symbols which need to be offset from __per_cpu_load
 * for the boot processor.
 */
#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
INIT_PER_CPU(gdt_page);
INIT_PER_CPU(irq_stack_union);

/*
 * Build-time check on the image size:
 */
. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
	   "kernel image bigger than KERNEL_IMAGE_SIZE");

#ifdef CONFIG_SMP
. = ASSERT((irq_stack_union == 0),
           "irq_stack_union is not at start of per-cpu area");
#endif

#endif /* CONFIG_X86_32 */

#ifdef CONFIG_KEXEC
#include <asm/kexec.h>

. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
           "kexec control code size is too big");
#endif