xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision b6dcefde) 
1/*
2 * ld script for the x86 kernel
3 *
4 * Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
5 *
6 * Modernisation, unification and other changes and fixes:
7 *   Copyright (C) 2007-2009  Sam Ravnborg <sam@ravnborg.org>
8 *
9 *
10 * Don't define absolute symbols until and unless you know that symbol
11 * value is should remain constant even if kernel image is relocated
12 * at run time. Absolute symbols are not relocated. If symbol value should
13 * change if kernel is relocated, make the symbol section relative and
14 * put it inside the section definition.
15 */
16
17#ifdef CONFIG_X86_32
18#define LOAD_OFFSET __PAGE_OFFSET
19#else
20#define LOAD_OFFSET __START_KERNEL_map
21#endif
22
23#include <asm-generic/vmlinux.lds.h>
24#include <asm/asm-offsets.h>
25#include <asm/thread_info.h>
26#include <asm/page_types.h>
27#include <asm/cache.h>
28#include <asm/boot.h>
29
30#undef i386     /* in case the preprocessor is a 32bit one */
31
32OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT)
33
34#ifdef CONFIG_X86_32
35OUTPUT_ARCH(i386)
36ENTRY(phys_startup_32)
37jiffies = jiffies_64;
38#else
39OUTPUT_ARCH(i386:x86-64)
40ENTRY(phys_startup_64)
41jiffies_64 = jiffies;
42#endif
43
44#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
45/*
46 * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA
47 * we retain large page mappings for boundaries spanning kernel text, rodata
48 * and data sections.
49 *
50 * However, kernel identity mappings will have different RWX permissions
51 * to the pages mapping to text and to the pages padding (which are freed) the
52 * text section. Hence kernel identity mappings will be broken to smaller
53 * pages. For 64-bit, kernel text and kernel identity mappings are different,
54 * so we can enable protection checks that come with CONFIG_DEBUG_RODATA,
55 * as well as retain 2MB large page mappings for kernel text.
56 */
57#define X64_ALIGN_DEBUG_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);
58
59#define X64_ALIGN_DEBUG_RODATA_END				\
60		. = ALIGN(HPAGE_SIZE);				\
61		__end_rodata_hpage_align = .;
62
63#else
64
65#define X64_ALIGN_DEBUG_RODATA_BEGIN
66#define X64_ALIGN_DEBUG_RODATA_END
67
68#endif
69
70PHDRS {
71	text PT_LOAD FLAGS(5);          /* R_E */
72	data PT_LOAD FLAGS(7);          /* RWE */
73#ifdef CONFIG_X86_64
74	user PT_LOAD FLAGS(5);          /* R_E */
75#ifdef CONFIG_SMP
76	percpu PT_LOAD FLAGS(6);        /* RW_ */
77#endif
78	init PT_LOAD FLAGS(7);          /* RWE */
79#endif
80	note PT_NOTE FLAGS(0);          /* ___ */
81}
82
83SECTIONS
84{
85#ifdef CONFIG_X86_32
86        . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
87        phys_startup_32 = startup_32 - LOAD_OFFSET;
88#else
89        . = __START_KERNEL;
90        phys_startup_64 = startup_64 - LOAD_OFFSET;
91#endif
92
93	/* Text and read-only data */
94	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
95		_text = .;
96		/* bootstrapping code */
97		HEAD_TEXT
98#ifdef CONFIG_X86_32
99		. = ALIGN(PAGE_SIZE);
100		*(.text.page_aligned)
101#endif
102		. = ALIGN(8);
103		_stext = .;
104		TEXT_TEXT
105		SCHED_TEXT
106		LOCK_TEXT
107		KPROBES_TEXT
108		IRQENTRY_TEXT
109		*(.fixup)
110		*(.gnu.warning)
111		/* End of text section */
112		_etext = .;
113	} :text = 0x9090
114
115	NOTES :text :note
116
117	EXCEPTION_TABLE(16) :text = 0x9090
118
119	X64_ALIGN_DEBUG_RODATA_BEGIN
120	RO_DATA(PAGE_SIZE)
121	X64_ALIGN_DEBUG_RODATA_END
122
123	/* Data */
124	.data : AT(ADDR(.data) - LOAD_OFFSET) {
125		/* Start of data section */
126		_sdata = .;
127
128		/* init_task */
129		INIT_TASK_DATA(THREAD_SIZE)
130
131#ifdef CONFIG_X86_32
132		/* 32 bit has nosave before _edata */
133		NOSAVE_DATA
134#endif
135
136		PAGE_ALIGNED_DATA(PAGE_SIZE)
137
138		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
139
140		DATA_DATA
141		CONSTRUCTORS
142
143		/* rarely changed data like cpu maps */
144		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
145
146		/* End of data section */
147		_edata = .;
148	} :data
149
150#ifdef CONFIG_X86_64
151
152#define VSYSCALL_ADDR (-10*1024*1024)
153
154#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET)
155#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET)
156
157#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0)
158#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET)
159
160	. = ALIGN(4096);
161	__vsyscall_0 = .;
162
163	. = VSYSCALL_ADDR;
164	.vsyscall_0 : AT(VLOAD(.vsyscall_0)) {
165		*(.vsyscall_0)
166	} :user
167
168	. = ALIGN(L1_CACHE_BYTES);
169	.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
170		*(.vsyscall_fn)
171	}
172
173	. = ALIGN(L1_CACHE_BYTES);
174	.vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) {
175		*(.vsyscall_gtod_data)
176	}
177
178	vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data);
179	.vsyscall_clock : AT(VLOAD(.vsyscall_clock)) {
180		*(.vsyscall_clock)
181	}
182	vsyscall_clock = VVIRT(.vsyscall_clock);
183
184
185	.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) {
186		*(.vsyscall_1)
187	}
188	.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) {
189		*(.vsyscall_2)
190	}
191
192	.vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) {
193		*(.vgetcpu_mode)
194	}
195	vgetcpu_mode = VVIRT(.vgetcpu_mode);
196
197	. = ALIGN(L1_CACHE_BYTES);
198	.jiffies : AT(VLOAD(.jiffies)) {
199		*(.jiffies)
200	}
201	jiffies = VVIRT(.jiffies);
202
203	.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) {
204		*(.vsyscall_3)
205	}
206
207	. = __vsyscall_0 + PAGE_SIZE;
208
209#undef VSYSCALL_ADDR
210#undef VLOAD_OFFSET
211#undef VLOAD
212#undef VVIRT_OFFSET
213#undef VVIRT
214
215#endif /* CONFIG_X86_64 */
216
217	/* Init code and data - will be freed after init */
218	. = ALIGN(PAGE_SIZE);
219	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
220		__init_begin = .; /* paired with __init_end */
221	}
222
223#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
224	/*
225	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
226	 * output PHDR, so the next output section - .init.text - should
227	 * start another segment - init.
228	 */
229	PERCPU_VADDR(0, :percpu)
230#endif
231
232	INIT_TEXT_SECTION(PAGE_SIZE)
233#ifdef CONFIG_X86_64
234	:init
235#endif
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	. = ALIGN(8);
246	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
247		__parainstructions = .;
248		*(.parainstructions)
249		__parainstructions_end = .;
250	}
251
252	. = ALIGN(8);
253	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
254		__alt_instructions = .;
255		*(.altinstructions)
256		__alt_instructions_end = .;
257	}
258
259	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
260		*(.altinstr_replacement)
261	}
262
263	/*
264	 * .exit.text is discard at runtime, not link time, to deal with
265	 *  references from .altinstructions and .eh_frame
266	 */
267	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
268		EXIT_TEXT
269	}
270
271	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
272		EXIT_DATA
273	}
274
275#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
276	PERCPU(PAGE_SIZE)
277#endif
278
279	. = ALIGN(PAGE_SIZE);
280
281	/* freed after init ends here */
282	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
283		__init_end = .;
284	}
285
286	/*
287	 * smp_locks might be freed after init
288	 * start/end must be page aligned
289	 */
290	. = ALIGN(PAGE_SIZE);
291	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
292		__smp_locks = .;
293		*(.smp_locks)
294		__smp_locks_end = .;
295		. = ALIGN(PAGE_SIZE);
296	}
297
298#ifdef CONFIG_X86_64
299	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
300		NOSAVE_DATA
301	}
302#endif
303
304	/* BSS */
305	. = ALIGN(PAGE_SIZE);
306	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
307		__bss_start = .;
308		*(.bss.page_aligned)
309		*(.bss)
310		. = ALIGN(4);
311		__bss_stop = .;
312	}
313
314	. = ALIGN(PAGE_SIZE);
315	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
316		__brk_base = .;
317		. += 64 * 1024;		/* 64k alignment slop space */
318		*(.brk_reservation)	/* areas brk users have reserved */
319		__brk_limit = .;
320	}
321
322	_end = .;
323
324        STABS_DEBUG
325        DWARF_DEBUG
326
327	/* Sections to be discarded */
328	DISCARDS
329	/DISCARD/ : { *(.eh_frame) }
330}
331
332
333#ifdef CONFIG_X86_32
334/*
335 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
336 */
337. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
338	   "kernel image bigger than KERNEL_IMAGE_SIZE");
339#else
340/*
341 * Per-cpu symbols which need to be offset from __per_cpu_load
342 * for the boot processor.
343 */
344#define INIT_PER_CPU(x) init_per_cpu__##x = per_cpu__##x + __per_cpu_load
345INIT_PER_CPU(gdt_page);
346INIT_PER_CPU(irq_stack_union);
347
348/*
349 * Build-time check on the image size:
350 */
351. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
352	   "kernel image bigger than KERNEL_IMAGE_SIZE");
353
354#ifdef CONFIG_SMP
355. = ASSERT((per_cpu__irq_stack_union == 0),
356           "irq_stack_union is not at start of per-cpu area");
357#endif
358
359#endif /* CONFIG_X86_32 */
360
361#ifdef CONFIG_KEXEC
362#include <asm/kexec.h>
363
364. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
365           "kexec control code size is too big");
366#endif
367
368