xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision d0b73b48) 
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(6);          /* RW_ */
73#ifdef CONFIG_X86_64
74#ifdef CONFIG_SMP
75	percpu PT_LOAD FLAGS(6);        /* RW_ */
76#endif
77	init PT_LOAD FLAGS(7);          /* RWE */
78#endif
79	note PT_NOTE FLAGS(0);          /* ___ */
80}
81
82SECTIONS
83{
84#ifdef CONFIG_X86_32
85        . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
86        phys_startup_32 = startup_32 - LOAD_OFFSET;
87#else
88        . = __START_KERNEL;
89        phys_startup_64 = startup_64 - LOAD_OFFSET;
90#endif
91
92	/* Text and read-only data */
93	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
94		_text = .;
95		/* bootstrapping code */
96		HEAD_TEXT
97#ifdef CONFIG_X86_32
98		. = ALIGN(PAGE_SIZE);
99		*(.text..page_aligned)
100#endif
101		. = ALIGN(8);
102		_stext = .;
103		TEXT_TEXT
104		SCHED_TEXT
105		LOCK_TEXT
106		KPROBES_TEXT
107		ENTRY_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#if defined(CONFIG_DEBUG_RODATA)
120	/* .text should occupy whole number of pages */
121	. = ALIGN(PAGE_SIZE);
122#endif
123	X64_ALIGN_DEBUG_RODATA_BEGIN
124	RO_DATA(PAGE_SIZE)
125	X64_ALIGN_DEBUG_RODATA_END
126
127	/* Data */
128	.data : AT(ADDR(.data) - LOAD_OFFSET) {
129		/* Start of data section */
130		_sdata = .;
131
132		/* init_task */
133		INIT_TASK_DATA(THREAD_SIZE)
134
135#ifdef CONFIG_X86_32
136		/* 32 bit has nosave before _edata */
137		NOSAVE_DATA
138#endif
139
140		PAGE_ALIGNED_DATA(PAGE_SIZE)
141
142		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
143
144		DATA_DATA
145		CONSTRUCTORS
146
147		/* rarely changed data like cpu maps */
148		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
149
150		/* End of data section */
151		_edata = .;
152	} :data
153
154#ifdef CONFIG_X86_64
155
156	. = ALIGN(PAGE_SIZE);
157	__vvar_page = .;
158
159	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
160		/* work around gold bug 13023 */
161		__vvar_beginning_hack = .;
162
163		/* Place all vvars at the offsets in asm/vvar.h. */
164#define EMIT_VVAR(name, offset) 			\
165		. = __vvar_beginning_hack + offset;	\
166		*(.vvar_ ## name)
167#define __VVAR_KERNEL_LDS
168#include <asm/vvar.h>
169#undef __VVAR_KERNEL_LDS
170#undef EMIT_VVAR
171
172	} :data
173
174       . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
175
176#endif /* CONFIG_X86_64 */
177
178	/* Init code and data - will be freed after init */
179	. = ALIGN(PAGE_SIZE);
180	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
181		__init_begin = .; /* paired with __init_end */
182	}
183
184#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
185	/*
186	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
187	 * output PHDR, so the next output section - .init.text - should
188	 * start another segment - init.
189	 */
190	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
191#endif
192
193	INIT_TEXT_SECTION(PAGE_SIZE)
194#ifdef CONFIG_X86_64
195	:init
196#endif
197
198	INIT_DATA_SECTION(16)
199
200	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
201		__x86_cpu_dev_start = .;
202		*(.x86_cpu_dev.init)
203		__x86_cpu_dev_end = .;
204	}
205
206	/*
207	 * start address and size of operations which during runtime
208	 * can be patched with virtualization friendly instructions or
209	 * baremetal native ones. Think page table operations.
210	 * Details in paravirt_types.h
211	 */
212	. = ALIGN(8);
213	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
214		__parainstructions = .;
215		*(.parainstructions)
216		__parainstructions_end = .;
217	}
218
219	/*
220	 * struct alt_inst entries. From the header (alternative.h):
221	 * "Alternative instructions for different CPU types or capabilities"
222	 * Think locking instructions on spinlocks.
223	 */
224	. = ALIGN(8);
225	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
226		__alt_instructions = .;
227		*(.altinstructions)
228		__alt_instructions_end = .;
229	}
230
231	/*
232	 * And here are the replacement instructions. The linker sticks
233	 * them as binary blobs. The .altinstructions has enough data to
234	 * get the address and the length of them to patch the kernel safely.
235	 */
236	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
237		*(.altinstr_replacement)
238	}
239
240	/*
241	 * struct iommu_table_entry entries are injected in this section.
242	 * It is an array of IOMMUs which during run time gets sorted depending
243	 * on its dependency order. After rootfs_initcall is complete
244	 * this section can be safely removed.
245	 */
246	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
247		__iommu_table = .;
248		*(.iommu_table)
249		__iommu_table_end = .;
250	}
251
252	. = ALIGN(8);
253	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
254		__apicdrivers = .;
255		*(.apicdrivers);
256		__apicdrivers_end = .;
257	}
258
259	. = ALIGN(8);
260	/*
261	 * .exit.text is discard at runtime, not link time, to deal with
262	 *  references from .altinstructions and .eh_frame
263	 */
264	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
265		EXIT_TEXT
266	}
267
268	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
269		EXIT_DATA
270	}
271
272#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
273	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
274#endif
275
276	. = ALIGN(PAGE_SIZE);
277
278	/* freed after init ends here */
279	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
280		__init_end = .;
281	}
282
283	/*
284	 * smp_locks might be freed after init
285	 * start/end must be page aligned
286	 */
287	. = ALIGN(PAGE_SIZE);
288	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
289		__smp_locks = .;
290		*(.smp_locks)
291		. = ALIGN(PAGE_SIZE);
292		__smp_locks_end = .;
293	}
294
295#ifdef CONFIG_X86_64
296	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
297		NOSAVE_DATA
298	}
299#endif
300
301	/* BSS */
302	. = ALIGN(PAGE_SIZE);
303	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
304		__bss_start = .;
305		*(.bss..page_aligned)
306		*(.bss)
307		. = ALIGN(PAGE_SIZE);
308		__bss_stop = .;
309	}
310
311	. = ALIGN(PAGE_SIZE);
312	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
313		__brk_base = .;
314		. += 64 * 1024;		/* 64k alignment slop space */
315		*(.brk_reservation)	/* areas brk users have reserved */
316		__brk_limit = .;
317	}
318
319	_end = .;
320
321        STABS_DEBUG
322        DWARF_DEBUG
323
324	/* Sections to be discarded */
325	DISCARDS
326	/DISCARD/ : { *(.eh_frame) }
327}
328
329
330#ifdef CONFIG_X86_32
331/*
332 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
333 */
334. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
335	   "kernel image bigger than KERNEL_IMAGE_SIZE");
336#else
337/*
338 * Per-cpu symbols which need to be offset from __per_cpu_load
339 * for the boot processor.
340 */
341#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
342INIT_PER_CPU(gdt_page);
343INIT_PER_CPU(irq_stack_union);
344
345/*
346 * Build-time check on the image size:
347 */
348. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
349	   "kernel image bigger than KERNEL_IMAGE_SIZE");
350
351#ifdef CONFIG_SMP
352. = ASSERT((irq_stack_union == 0),
353           "irq_stack_union is not at start of per-cpu area");
354#endif
355
356#endif /* CONFIG_X86_32 */
357
358#ifdef CONFIG_KEXEC
359#include <asm/kexec.h>
360
361. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
362           "kexec control code size is too big");
363#endif
364
365