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1/*
2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8
9#include <linux/mm.h>
10#include <linux/kexec.h>
11#include <linux/string.h>
12#include <linux/gfp.h>
13#include <linux/reboot.h>
14#include <linux/numa.h>
15#include <linux/ftrace.h>
16#include <linux/io.h>
17#include <linux/suspend.h>
18
19#include <asm/pgtable.h>
20#include <asm/tlbflush.h>
21#include <asm/mmu_context.h>
22#include <asm/debugreg.h>
23
24static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
25 unsigned long addr)
26{
27 pud_t *pud;
28 pmd_t *pmd;
29 struct page *page;
30 int result = -ENOMEM;
31
32 addr &= PMD_MASK;
33 pgd += pgd_index(addr);
34 if (!pgd_present(*pgd)) {
35 page = kimage_alloc_control_pages(image, 0);
36 if (!page)
37 goto out;
38 pud = (pud_t *)page_address(page);
39 clear_page(pud);
40 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
41 }
42 pud = pud_offset(pgd, addr);
43 if (!pud_present(*pud)) {
44 page = kimage_alloc_control_pages(image, 0);
45 if (!page)
46 goto out;
47 pmd = (pmd_t *)page_address(page);
48 clear_page(pmd);
49 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
50 }
51 pmd = pmd_offset(pud, addr);
52 if (!pmd_present(*pmd))
53 set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
54 result = 0;
55out:
56 return result;
57}
58
59static void init_level2_page(pmd_t *level2p, unsigned long addr)
60{
61 unsigned long end_addr;
62
63 addr &= PAGE_MASK;
64 end_addr = addr + PUD_SIZE;
65 while (addr < end_addr) {
66 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
67 addr += PMD_SIZE;
68 }
69}
70
71static int init_level3_page(struct kimage *image, pud_t *level3p,
72 unsigned long addr, unsigned long last_addr)
73{
74 unsigned long end_addr;
75 int result;
76
77 result = 0;
78 addr &= PAGE_MASK;
79 end_addr = addr + PGDIR_SIZE;
80 while ((addr < last_addr) && (addr < end_addr)) {
81 struct page *page;
82 pmd_t *level2p;
83
84 page = kimage_alloc_control_pages(image, 0);
85 if (!page) {
86 result = -ENOMEM;
87 goto out;
88 }
89 level2p = (pmd_t *)page_address(page);
90 init_level2_page(level2p, addr);
91 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
92 addr += PUD_SIZE;
93 }
94 /* clear the unused entries */
95 while (addr < end_addr) {
96 pud_clear(level3p++);
97 addr += PUD_SIZE;
98 }
99out:
100 return result;
101}
102
103
104static int init_level4_page(struct kimage *image, pgd_t *level4p,
105 unsigned long addr, unsigned long last_addr)
106{
107 unsigned long end_addr;
108 int result;
109
110 result = 0;
111 addr &= PAGE_MASK;
112 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
113 while ((addr < last_addr) && (addr < end_addr)) {
114 struct page *page;
115 pud_t *level3p;
116
117 page = kimage_alloc_control_pages(image, 0);
118 if (!page) {
119 result = -ENOMEM;
120 goto out;
121 }
122 level3p = (pud_t *)page_address(page);
123 result = init_level3_page(image, level3p, addr, last_addr);
124 if (result)
125 goto out;
126 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
127 addr += PGDIR_SIZE;
128 }
129 /* clear the unused entries */
130 while (addr < end_addr) {
131 pgd_clear(level4p++);
132 addr += PGDIR_SIZE;
133 }
134out:
135 return result;
136}
137
138static void free_transition_pgtable(struct kimage *image)
139{
140 free_page((unsigned long)image->arch.pud);
141 free_page((unsigned long)image->arch.pmd);
142 free_page((unsigned long)image->arch.pte);
143}
144
145static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
146{
147 pud_t *pud;
148 pmd_t *pmd;
149 pte_t *pte;
150 unsigned long vaddr, paddr;
151 int result = -ENOMEM;
152
153 vaddr = (unsigned long)relocate_kernel;
154 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
155 pgd += pgd_index(vaddr);
156 if (!pgd_present(*pgd)) {
157 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
158 if (!pud)
159 goto err;
160 image->arch.pud = pud;
161 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
162 }
163 pud = pud_offset(pgd, vaddr);
164 if (!pud_present(*pud)) {
165 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
166 if (!pmd)
167 goto err;
168 image->arch.pmd = pmd;
169 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
170 }
171 pmd = pmd_offset(pud, vaddr);
172 if (!pmd_present(*pmd)) {
173 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
174 if (!pte)
175 goto err;
176 image->arch.pte = pte;
177 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
178 }
179 pte = pte_offset_kernel(pmd, vaddr);
180 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
181 return 0;
182err:
183 free_transition_pgtable(image);
184 return result;
185}
186
187
188static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
189{
190 pgd_t *level4p;
191 int result;
192 level4p = (pgd_t *)__va(start_pgtable);
193 result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
194 if (result)
195 return result;
196 /*
197 * image->start may be outside 0 ~ max_pfn, for example when
198 * jump back to original kernel from kexeced kernel
199 */
200 result = init_one_level2_page(image, level4p, image->start);
201 if (result)
202 return result;
203 return init_transition_pgtable(image, level4p);
204}
205
206static void set_idt(void *newidt, u16 limit)
207{
208 struct desc_ptr curidt;
209
210 /* x86-64 supports unaliged loads & stores */
211 curidt.size = limit;
212 curidt.address = (unsigned long)newidt;
213
214 __asm__ __volatile__ (
215 "lidtq %0\n"
216 : : "m" (curidt)
217 );
218};
219
220
221static void set_gdt(void *newgdt, u16 limit)
222{
223 struct desc_ptr curgdt;
224
225 /* x86-64 supports unaligned loads & stores */
226 curgdt.size = limit;
227 curgdt.address = (unsigned long)newgdt;
228
229 __asm__ __volatile__ (
230 "lgdtq %0\n"
231 : : "m" (curgdt)
232 );
233};
234
235static void load_segments(void)
236{
237 __asm__ __volatile__ (
238 "\tmovl %0,%%ds\n"
239 "\tmovl %0,%%es\n"
240 "\tmovl %0,%%ss\n"
241 "\tmovl %0,%%fs\n"
242 "\tmovl %0,%%gs\n"
243 : : "a" (__KERNEL_DS) : "memory"
244 );
245}
246
247int machine_kexec_prepare(struct kimage *image)
248{
249 unsigned long start_pgtable;
250 int result;
251
252 /* Calculate the offsets */
253 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
254
255 /* Setup the identity mapped 64bit page table */
256 result = init_pgtable(image, start_pgtable);
257 if (result)
258 return result;
259
260 return 0;
261}
262
263void machine_kexec_cleanup(struct kimage *image)
264{
265 free_transition_pgtable(image);
266}
267
268/*
269 * Do not allocate memory (or fail in any way) in machine_kexec().
270 * We are past the point of no return, committed to rebooting now.
271 */
272void machine_kexec(struct kimage *image)
273{
274 unsigned long page_list[PAGES_NR];
275 void *control_page;
276 int save_ftrace_enabled;
277
278#ifdef CONFIG_KEXEC_JUMP
279 if (image->preserve_context)
280 save_processor_state();
281#endif
282
283 save_ftrace_enabled = __ftrace_enabled_save();
284
285 /* Interrupts aren't acceptable while we reboot */
286 local_irq_disable();
287 hw_breakpoint_disable();
288
289 if (image->preserve_context) {
290#ifdef CONFIG_X86_IO_APIC
291 /*
292 * We need to put APICs in legacy mode so that we can
293 * get timer interrupts in second kernel. kexec/kdump
294 * paths already have calls to disable_IO_APIC() in
295 * one form or other. kexec jump path also need
296 * one.
297 */
298 disable_IO_APIC();
299#endif
300 }
301
302 control_page = page_address(image->control_code_page) + PAGE_SIZE;
303 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
304
305 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
306 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
307 page_list[PA_TABLE_PAGE] =
308 (unsigned long)__pa(page_address(image->control_code_page));
309
310 if (image->type == KEXEC_TYPE_DEFAULT)
311 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
312 << PAGE_SHIFT);
313
314 /*
315 * The segment registers are funny things, they have both a
316 * visible and an invisible part. Whenever the visible part is
317 * set to a specific selector, the invisible part is loaded
318 * with from a table in memory. At no other time is the
319 * descriptor table in memory accessed.
320 *
321 * I take advantage of this here by force loading the
322 * segments, before I zap the gdt with an invalid value.
323 */
324 load_segments();
325 /*
326 * The gdt & idt are now invalid.
327 * If you want to load them you must set up your own idt & gdt.
328 */
329 set_gdt(phys_to_virt(0), 0);
330 set_idt(phys_to_virt(0), 0);
331
332 /* now call it */
333 image->start = relocate_kernel((unsigned long)image->head,
334 (unsigned long)page_list,
335 image->start,
336 image->preserve_context);
337
338#ifdef CONFIG_KEXEC_JUMP
339 if (image->preserve_context)
340 restore_processor_state();
341#endif
342
343 __ftrace_enabled_restore(save_ftrace_enabled);
344}
345
346void arch_crash_save_vmcoreinfo(void)
347{
348 VMCOREINFO_SYMBOL(phys_base);
349 VMCOREINFO_SYMBOL(init_level4_pgt);
350
351#ifdef CONFIG_NUMA
352 VMCOREINFO_SYMBOL(node_data);
353 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
354#endif
355}
356
1/*
2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8
9#define pr_fmt(fmt) "kexec: " fmt
10
11#include <linux/mm.h>
12#include <linux/kexec.h>
13#include <linux/string.h>
14#include <linux/gfp.h>
15#include <linux/reboot.h>
16#include <linux/numa.h>
17#include <linux/ftrace.h>
18#include <linux/io.h>
19#include <linux/suspend.h>
20#include <linux/vmalloc.h>
21
22#include <asm/init.h>
23#include <asm/pgtable.h>
24#include <asm/tlbflush.h>
25#include <asm/mmu_context.h>
26#include <asm/io_apic.h>
27#include <asm/debugreg.h>
28#include <asm/kexec-bzimage64.h>
29#include <asm/setup.h>
30
31#ifdef CONFIG_KEXEC_FILE
32static struct kexec_file_ops *kexec_file_loaders[] = {
33 &kexec_bzImage64_ops,
34};
35#endif
36
37static void free_transition_pgtable(struct kimage *image)
38{
39 free_page((unsigned long)image->arch.pud);
40 free_page((unsigned long)image->arch.pmd);
41 free_page((unsigned long)image->arch.pte);
42}
43
44static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
45{
46 pud_t *pud;
47 pmd_t *pmd;
48 pte_t *pte;
49 unsigned long vaddr, paddr;
50 int result = -ENOMEM;
51
52 vaddr = (unsigned long)relocate_kernel;
53 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
54 pgd += pgd_index(vaddr);
55 if (!pgd_present(*pgd)) {
56 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
57 if (!pud)
58 goto err;
59 image->arch.pud = pud;
60 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
61 }
62 pud = pud_offset(pgd, vaddr);
63 if (!pud_present(*pud)) {
64 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
65 if (!pmd)
66 goto err;
67 image->arch.pmd = pmd;
68 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
69 }
70 pmd = pmd_offset(pud, vaddr);
71 if (!pmd_present(*pmd)) {
72 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
73 if (!pte)
74 goto err;
75 image->arch.pte = pte;
76 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
77 }
78 pte = pte_offset_kernel(pmd, vaddr);
79 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
80 return 0;
81err:
82 free_transition_pgtable(image);
83 return result;
84}
85
86static void *alloc_pgt_page(void *data)
87{
88 struct kimage *image = (struct kimage *)data;
89 struct page *page;
90 void *p = NULL;
91
92 page = kimage_alloc_control_pages(image, 0);
93 if (page) {
94 p = page_address(page);
95 clear_page(p);
96 }
97
98 return p;
99}
100
101static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
102{
103 struct x86_mapping_info info = {
104 .alloc_pgt_page = alloc_pgt_page,
105 .context = image,
106 .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
107 };
108 unsigned long mstart, mend;
109 pgd_t *level4p;
110 int result;
111 int i;
112
113 level4p = (pgd_t *)__va(start_pgtable);
114 clear_page(level4p);
115 for (i = 0; i < nr_pfn_mapped; i++) {
116 mstart = pfn_mapped[i].start << PAGE_SHIFT;
117 mend = pfn_mapped[i].end << PAGE_SHIFT;
118
119 result = kernel_ident_mapping_init(&info,
120 level4p, mstart, mend);
121 if (result)
122 return result;
123 }
124
125 /*
126 * segments's mem ranges could be outside 0 ~ max_pfn,
127 * for example when jump back to original kernel from kexeced kernel.
128 * or first kernel is booted with user mem map, and second kernel
129 * could be loaded out of that range.
130 */
131 for (i = 0; i < image->nr_segments; i++) {
132 mstart = image->segment[i].mem;
133 mend = mstart + image->segment[i].memsz;
134
135 result = kernel_ident_mapping_init(&info,
136 level4p, mstart, mend);
137
138 if (result)
139 return result;
140 }
141
142 return init_transition_pgtable(image, level4p);
143}
144
145static void set_idt(void *newidt, u16 limit)
146{
147 struct desc_ptr curidt;
148
149 /* x86-64 supports unaliged loads & stores */
150 curidt.size = limit;
151 curidt.address = (unsigned long)newidt;
152
153 __asm__ __volatile__ (
154 "lidtq %0\n"
155 : : "m" (curidt)
156 );
157};
158
159
160static void set_gdt(void *newgdt, u16 limit)
161{
162 struct desc_ptr curgdt;
163
164 /* x86-64 supports unaligned loads & stores */
165 curgdt.size = limit;
166 curgdt.address = (unsigned long)newgdt;
167
168 __asm__ __volatile__ (
169 "lgdtq %0\n"
170 : : "m" (curgdt)
171 );
172};
173
174static void load_segments(void)
175{
176 __asm__ __volatile__ (
177 "\tmovl %0,%%ds\n"
178 "\tmovl %0,%%es\n"
179 "\tmovl %0,%%ss\n"
180 "\tmovl %0,%%fs\n"
181 "\tmovl %0,%%gs\n"
182 : : "a" (__KERNEL_DS) : "memory"
183 );
184}
185
186#ifdef CONFIG_KEXEC_FILE
187/* Update purgatory as needed after various image segments have been prepared */
188static int arch_update_purgatory(struct kimage *image)
189{
190 int ret = 0;
191
192 if (!image->file_mode)
193 return 0;
194
195 /* Setup copying of backup region */
196 if (image->type == KEXEC_TYPE_CRASH) {
197 ret = kexec_purgatory_get_set_symbol(image, "backup_dest",
198 &image->arch.backup_load_addr,
199 sizeof(image->arch.backup_load_addr), 0);
200 if (ret)
201 return ret;
202
203 ret = kexec_purgatory_get_set_symbol(image, "backup_src",
204 &image->arch.backup_src_start,
205 sizeof(image->arch.backup_src_start), 0);
206 if (ret)
207 return ret;
208
209 ret = kexec_purgatory_get_set_symbol(image, "backup_sz",
210 &image->arch.backup_src_sz,
211 sizeof(image->arch.backup_src_sz), 0);
212 if (ret)
213 return ret;
214 }
215
216 return ret;
217}
218#else /* !CONFIG_KEXEC_FILE */
219static inline int arch_update_purgatory(struct kimage *image)
220{
221 return 0;
222}
223#endif /* CONFIG_KEXEC_FILE */
224
225int machine_kexec_prepare(struct kimage *image)
226{
227 unsigned long start_pgtable;
228 int result;
229
230 /* Calculate the offsets */
231 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
232
233 /* Setup the identity mapped 64bit page table */
234 result = init_pgtable(image, start_pgtable);
235 if (result)
236 return result;
237
238 /* update purgatory as needed */
239 result = arch_update_purgatory(image);
240 if (result)
241 return result;
242
243 return 0;
244}
245
246void machine_kexec_cleanup(struct kimage *image)
247{
248 free_transition_pgtable(image);
249}
250
251/*
252 * Do not allocate memory (or fail in any way) in machine_kexec().
253 * We are past the point of no return, committed to rebooting now.
254 */
255void machine_kexec(struct kimage *image)
256{
257 unsigned long page_list[PAGES_NR];
258 void *control_page;
259 int save_ftrace_enabled;
260
261#ifdef CONFIG_KEXEC_JUMP
262 if (image->preserve_context)
263 save_processor_state();
264#endif
265
266 save_ftrace_enabled = __ftrace_enabled_save();
267
268 /* Interrupts aren't acceptable while we reboot */
269 local_irq_disable();
270 hw_breakpoint_disable();
271
272 if (image->preserve_context) {
273#ifdef CONFIG_X86_IO_APIC
274 /*
275 * We need to put APICs in legacy mode so that we can
276 * get timer interrupts in second kernel. kexec/kdump
277 * paths already have calls to disable_IO_APIC() in
278 * one form or other. kexec jump path also need
279 * one.
280 */
281 disable_IO_APIC();
282#endif
283 }
284
285 control_page = page_address(image->control_code_page) + PAGE_SIZE;
286 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
287
288 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
289 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
290 page_list[PA_TABLE_PAGE] =
291 (unsigned long)__pa(page_address(image->control_code_page));
292
293 if (image->type == KEXEC_TYPE_DEFAULT)
294 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
295 << PAGE_SHIFT);
296
297 /*
298 * The segment registers are funny things, they have both a
299 * visible and an invisible part. Whenever the visible part is
300 * set to a specific selector, the invisible part is loaded
301 * with from a table in memory. At no other time is the
302 * descriptor table in memory accessed.
303 *
304 * I take advantage of this here by force loading the
305 * segments, before I zap the gdt with an invalid value.
306 */
307 load_segments();
308 /*
309 * The gdt & idt are now invalid.
310 * If you want to load them you must set up your own idt & gdt.
311 */
312 set_gdt(phys_to_virt(0), 0);
313 set_idt(phys_to_virt(0), 0);
314
315 /* now call it */
316 image->start = relocate_kernel((unsigned long)image->head,
317 (unsigned long)page_list,
318 image->start,
319 image->preserve_context);
320
321#ifdef CONFIG_KEXEC_JUMP
322 if (image->preserve_context)
323 restore_processor_state();
324#endif
325
326 __ftrace_enabled_restore(save_ftrace_enabled);
327}
328
329void arch_crash_save_vmcoreinfo(void)
330{
331 VMCOREINFO_SYMBOL(phys_base);
332 VMCOREINFO_SYMBOL(init_level4_pgt);
333
334#ifdef CONFIG_NUMA
335 VMCOREINFO_SYMBOL(node_data);
336 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
337#endif
338 vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
339 kaslr_offset());
340}
341
342/* arch-dependent functionality related to kexec file-based syscall */
343
344#ifdef CONFIG_KEXEC_FILE
345int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
346 unsigned long buf_len)
347{
348 int i, ret = -ENOEXEC;
349 struct kexec_file_ops *fops;
350
351 for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
352 fops = kexec_file_loaders[i];
353 if (!fops || !fops->probe)
354 continue;
355
356 ret = fops->probe(buf, buf_len);
357 if (!ret) {
358 image->fops = fops;
359 return ret;
360 }
361 }
362
363 return ret;
364}
365
366void *arch_kexec_kernel_image_load(struct kimage *image)
367{
368 vfree(image->arch.elf_headers);
369 image->arch.elf_headers = NULL;
370
371 if (!image->fops || !image->fops->load)
372 return ERR_PTR(-ENOEXEC);
373
374 return image->fops->load(image, image->kernel_buf,
375 image->kernel_buf_len, image->initrd_buf,
376 image->initrd_buf_len, image->cmdline_buf,
377 image->cmdline_buf_len);
378}
379
380int arch_kimage_file_post_load_cleanup(struct kimage *image)
381{
382 if (!image->fops || !image->fops->cleanup)
383 return 0;
384
385 return image->fops->cleanup(image->image_loader_data);
386}
387
388#ifdef CONFIG_KEXEC_VERIFY_SIG
389int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
390 unsigned long kernel_len)
391{
392 if (!image->fops || !image->fops->verify_sig) {
393 pr_debug("kernel loader does not support signature verification.");
394 return -EKEYREJECTED;
395 }
396
397 return image->fops->verify_sig(kernel, kernel_len);
398}
399#endif
400
401/*
402 * Apply purgatory relocations.
403 *
404 * ehdr: Pointer to elf headers
405 * sechdrs: Pointer to section headers.
406 * relsec: section index of SHT_RELA section.
407 *
408 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
409 */
410int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
411 Elf64_Shdr *sechdrs, unsigned int relsec)
412{
413 unsigned int i;
414 Elf64_Rela *rel;
415 Elf64_Sym *sym;
416 void *location;
417 Elf64_Shdr *section, *symtabsec;
418 unsigned long address, sec_base, value;
419 const char *strtab, *name, *shstrtab;
420
421 /*
422 * ->sh_offset has been modified to keep the pointer to section
423 * contents in memory
424 */
425 rel = (void *)sechdrs[relsec].sh_offset;
426
427 /* Section to which relocations apply */
428 section = &sechdrs[sechdrs[relsec].sh_info];
429
430 pr_debug("Applying relocate section %u to %u\n", relsec,
431 sechdrs[relsec].sh_info);
432
433 /* Associated symbol table */
434 symtabsec = &sechdrs[sechdrs[relsec].sh_link];
435
436 /* String table */
437 if (symtabsec->sh_link >= ehdr->e_shnum) {
438 /* Invalid strtab section number */
439 pr_err("Invalid string table section index %d\n",
440 symtabsec->sh_link);
441 return -ENOEXEC;
442 }
443
444 strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;
445
446 /* section header string table */
447 shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;
448
449 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
450
451 /*
452 * rel[i].r_offset contains byte offset from beginning
453 * of section to the storage unit affected.
454 *
455 * This is location to update (->sh_offset). This is temporary
456 * buffer where section is currently loaded. This will finally
457 * be loaded to a different address later, pointed to by
458 * ->sh_addr. kexec takes care of moving it
459 * (kexec_load_segment()).
460 */
461 location = (void *)(section->sh_offset + rel[i].r_offset);
462
463 /* Final address of the location */
464 address = section->sh_addr + rel[i].r_offset;
465
466 /*
467 * rel[i].r_info contains information about symbol table index
468 * w.r.t which relocation must be made and type of relocation
469 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
470 * these respectively.
471 */
472 sym = (Elf64_Sym *)symtabsec->sh_offset +
473 ELF64_R_SYM(rel[i].r_info);
474
475 if (sym->st_name)
476 name = strtab + sym->st_name;
477 else
478 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
479
480 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
481 name, sym->st_info, sym->st_shndx, sym->st_value,
482 sym->st_size);
483
484 if (sym->st_shndx == SHN_UNDEF) {
485 pr_err("Undefined symbol: %s\n", name);
486 return -ENOEXEC;
487 }
488
489 if (sym->st_shndx == SHN_COMMON) {
490 pr_err("symbol '%s' in common section\n", name);
491 return -ENOEXEC;
492 }
493
494 if (sym->st_shndx == SHN_ABS)
495 sec_base = 0;
496 else if (sym->st_shndx >= ehdr->e_shnum) {
497 pr_err("Invalid section %d for symbol %s\n",
498 sym->st_shndx, name);
499 return -ENOEXEC;
500 } else
501 sec_base = sechdrs[sym->st_shndx].sh_addr;
502
503 value = sym->st_value;
504 value += sec_base;
505 value += rel[i].r_addend;
506
507 switch (ELF64_R_TYPE(rel[i].r_info)) {
508 case R_X86_64_NONE:
509 break;
510 case R_X86_64_64:
511 *(u64 *)location = value;
512 break;
513 case R_X86_64_32:
514 *(u32 *)location = value;
515 if (value != *(u32 *)location)
516 goto overflow;
517 break;
518 case R_X86_64_32S:
519 *(s32 *)location = value;
520 if ((s64)value != *(s32 *)location)
521 goto overflow;
522 break;
523 case R_X86_64_PC32:
524 value -= (u64)address;
525 *(u32 *)location = value;
526 break;
527 default:
528 pr_err("Unknown rela relocation: %llu\n",
529 ELF64_R_TYPE(rel[i].r_info));
530 return -ENOEXEC;
531 }
532 }
533 return 0;
534
535overflow:
536 pr_err("Overflow in relocation type %d value 0x%lx\n",
537 (int)ELF64_R_TYPE(rel[i].r_info), value);
538 return -ENOEXEC;
539}
540#endif /* CONFIG_KEXEC_FILE */