xref: /openbmc/linux/arch/x86/kernel/vmlinux.lds.S (revision 82003e04)
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)
45/*
46 * On 64-bit, align RODATA to 2MB so we retain large page mappings for
47 * boundaries spanning kernel text, rodata and data sections.
48 *
49 * However, kernel identity mappings will have different RWX permissions
50 * to the pages mapping to text and to the pages padding (which are freed) the
51 * text section. Hence kernel identity mappings will be broken to smaller
52 * pages. For 64-bit, kernel text and kernel identity mappings are different,
53 * so we can enable protection checks as well as retain 2MB large page
54 * mappings for kernel text.
55 */
56#define X64_ALIGN_RODATA_BEGIN	. = ALIGN(HPAGE_SIZE);
57
58#define X64_ALIGN_RODATA_END					\
59		. = ALIGN(HPAGE_SIZE);				\
60		__end_rodata_hpage_align = .;
61
62#else
63
64#define X64_ALIGN_RODATA_BEGIN
65#define X64_ALIGN_RODATA_END
66
67#endif
68
69PHDRS {
70	text PT_LOAD FLAGS(5);          /* R_E */
71	data PT_LOAD FLAGS(6);          /* RW_ */
72#ifdef CONFIG_X86_64
73#ifdef CONFIG_SMP
74	percpu PT_LOAD FLAGS(6);        /* RW_ */
75#endif
76	init PT_LOAD FLAGS(7);          /* RWE */
77#endif
78	note PT_NOTE FLAGS(0);          /* ___ */
79}
80
81SECTIONS
82{
83#ifdef CONFIG_X86_32
84	. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
85	phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET);
86#else
87	. = __START_KERNEL;
88	phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET);
89#endif
90
91	/* Text and read-only data */
92	.text :  AT(ADDR(.text) - LOAD_OFFSET) {
93		_text = .;
94		/* bootstrapping code */
95		HEAD_TEXT
96		. = ALIGN(8);
97		_stext = .;
98		TEXT_TEXT
99		SCHED_TEXT
100		CPUIDLE_TEXT
101		LOCK_TEXT
102		KPROBES_TEXT
103		ENTRY_TEXT
104		IRQENTRY_TEXT
105		SOFTIRQENTRY_TEXT
106		*(.fixup)
107		*(.gnu.warning)
108		/* End of text section */
109		_etext = .;
110	} :text = 0x9090
111
112	NOTES :text :note
113
114	EXCEPTION_TABLE(16) :text = 0x9090
115
116	/* .text should occupy whole number of pages */
117	. = ALIGN(PAGE_SIZE);
118	X64_ALIGN_RODATA_BEGIN
119	RO_DATA(PAGE_SIZE)
120	X64_ALIGN_RODATA_END
121
122	/* Data */
123	.data : AT(ADDR(.data) - LOAD_OFFSET) {
124		/* Start of data section */
125		_sdata = .;
126
127		/* init_task */
128		INIT_TASK_DATA(THREAD_SIZE)
129
130#ifdef CONFIG_X86_32
131		/* 32 bit has nosave before _edata */
132		NOSAVE_DATA
133#endif
134
135		PAGE_ALIGNED_DATA(PAGE_SIZE)
136
137		CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
138
139		DATA_DATA
140		CONSTRUCTORS
141
142		/* rarely changed data like cpu maps */
143		READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
144
145		/* End of data section */
146		_edata = .;
147	} :data
148
149
150	. = ALIGN(PAGE_SIZE);
151	__vvar_page = .;
152
153	.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
154		/* work around gold bug 13023 */
155		__vvar_beginning_hack = .;
156
157		/* Place all vvars at the offsets in asm/vvar.h. */
158#define EMIT_VVAR(name, offset) 			\
159		. = __vvar_beginning_hack + offset;	\
160		*(.vvar_ ## name)
161#define __VVAR_KERNEL_LDS
162#include <asm/vvar.h>
163#undef __VVAR_KERNEL_LDS
164#undef EMIT_VVAR
165
166		/*
167		 * Pad the rest of the page with zeros.  Otherwise the loader
168		 * can leave garbage here.
169		 */
170		. = __vvar_beginning_hack + PAGE_SIZE;
171	} :data
172
173       . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
174
175	/* Init code and data - will be freed after init */
176	. = ALIGN(PAGE_SIZE);
177	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
178		__init_begin = .; /* paired with __init_end */
179	}
180
181#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
182	/*
183	 * percpu offsets are zero-based on SMP.  PERCPU_VADDR() changes the
184	 * output PHDR, so the next output section - .init.text - should
185	 * start another segment - init.
186	 */
187	PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
188	ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START,
189	       "per-CPU data too large - increase CONFIG_PHYSICAL_START")
190#endif
191
192	INIT_TEXT_SECTION(PAGE_SIZE)
193#ifdef CONFIG_X86_64
194	:init
195#endif
196
197	/*
198	 * Section for code used exclusively before alternatives are run. All
199	 * references to such code must be patched out by alternatives, normally
200	 * by using X86_FEATURE_ALWAYS CPU feature bit.
201	 *
202	 * See static_cpu_has() for an example.
203	 */
204	.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
205		*(.altinstr_aux)
206	}
207
208	INIT_DATA_SECTION(16)
209
210	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
211		__x86_cpu_dev_start = .;
212		*(.x86_cpu_dev.init)
213		__x86_cpu_dev_end = .;
214	}
215
216#ifdef CONFIG_X86_INTEL_MID
217	.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
218								LOAD_OFFSET) {
219		__x86_intel_mid_dev_start = .;
220		*(.x86_intel_mid_dev.init)
221		__x86_intel_mid_dev_end = .;
222	}
223#endif
224
225	/*
226	 * start address and size of operations which during runtime
227	 * can be patched with virtualization friendly instructions or
228	 * baremetal native ones. Think page table operations.
229	 * Details in paravirt_types.h
230	 */
231	. = ALIGN(8);
232	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
233		__parainstructions = .;
234		*(.parainstructions)
235		__parainstructions_end = .;
236	}
237
238	/*
239	 * struct alt_inst entries. From the header (alternative.h):
240	 * "Alternative instructions for different CPU types or capabilities"
241	 * Think locking instructions on spinlocks.
242	 */
243	. = ALIGN(8);
244	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
245		__alt_instructions = .;
246		*(.altinstructions)
247		__alt_instructions_end = .;
248	}
249
250	/*
251	 * And here are the replacement instructions. The linker sticks
252	 * them as binary blobs. The .altinstructions has enough data to
253	 * get the address and the length of them to patch the kernel safely.
254	 */
255	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
256		*(.altinstr_replacement)
257	}
258
259	/*
260	 * struct iommu_table_entry entries are injected in this section.
261	 * It is an array of IOMMUs which during run time gets sorted depending
262	 * on its dependency order. After rootfs_initcall is complete
263	 * this section can be safely removed.
264	 */
265	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
266		__iommu_table = .;
267		*(.iommu_table)
268		__iommu_table_end = .;
269	}
270
271	. = ALIGN(8);
272	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
273		__apicdrivers = .;
274		*(.apicdrivers);
275		__apicdrivers_end = .;
276	}
277
278	. = ALIGN(8);
279	/*
280	 * .exit.text is discard at runtime, not link time, to deal with
281	 *  references from .altinstructions and .eh_frame
282	 */
283	.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
284		EXIT_TEXT
285	}
286
287	.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
288		EXIT_DATA
289	}
290
291#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
292	PERCPU_SECTION(INTERNODE_CACHE_BYTES)
293#endif
294
295	. = ALIGN(PAGE_SIZE);
296
297	/* freed after init ends here */
298	.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
299		__init_end = .;
300	}
301
302	/*
303	 * smp_locks might be freed after init
304	 * start/end must be page aligned
305	 */
306	. = ALIGN(PAGE_SIZE);
307	.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
308		__smp_locks = .;
309		*(.smp_locks)
310		. = ALIGN(PAGE_SIZE);
311		__smp_locks_end = .;
312	}
313
314#ifdef CONFIG_X86_64
315	.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
316		NOSAVE_DATA
317	}
318#endif
319
320	/* BSS */
321	. = ALIGN(PAGE_SIZE);
322	.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
323		__bss_start = .;
324		*(.bss..page_aligned)
325		*(.bss)
326		. = ALIGN(PAGE_SIZE);
327		__bss_stop = .;
328	}
329
330	. = ALIGN(PAGE_SIZE);
331	.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
332		__brk_base = .;
333		. += 64 * 1024;		/* 64k alignment slop space */
334		*(.brk_reservation)	/* areas brk users have reserved */
335		__brk_limit = .;
336	}
337
338	. = ALIGN(PAGE_SIZE);		/* keep VO_INIT_SIZE page aligned */
339	_end = .;
340
341        STABS_DEBUG
342        DWARF_DEBUG
343
344	/* Sections to be discarded */
345	DISCARDS
346	/DISCARD/ : {
347		*(.eh_frame)
348		*(__func_stack_frame_non_standard)
349	}
350}
351
352
353#ifdef CONFIG_X86_32
354/*
355 * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
356 */
357. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
358	   "kernel image bigger than KERNEL_IMAGE_SIZE");
359#else
360/*
361 * Per-cpu symbols which need to be offset from __per_cpu_load
362 * for the boot processor.
363 */
364#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
365INIT_PER_CPU(gdt_page);
366INIT_PER_CPU(irq_stack_union);
367
368/*
369 * Build-time check on the image size:
370 */
371. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
372	   "kernel image bigger than KERNEL_IMAGE_SIZE");
373
374#ifdef CONFIG_SMP
375. = ASSERT((irq_stack_union == 0),
376           "irq_stack_union is not at start of per-cpu area");
377#endif
378
379#endif /* CONFIG_X86_32 */
380
381#ifdef CONFIG_KEXEC_CORE
382#include <asm/kexec.h>
383
384. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
385           "kexec control code size is too big");
386#endif
387
388