xref: /openbmc/linux/arch/powerpc/kernel/vdso.c (revision 78bb17f7)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 /*
4  *    Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
5  *			 <benh@kernel.crashing.org>
6  */
7 
8 #include <linux/errno.h>
9 #include <linux/sched.h>
10 #include <linux/kernel.h>
11 #include <linux/mm.h>
12 #include <linux/smp.h>
13 #include <linux/stddef.h>
14 #include <linux/unistd.h>
15 #include <linux/slab.h>
16 #include <linux/user.h>
17 #include <linux/elf.h>
18 #include <linux/security.h>
19 #include <linux/memblock.h>
20 
21 #include <asm/pgtable.h>
22 #include <asm/processor.h>
23 #include <asm/mmu.h>
24 #include <asm/mmu_context.h>
25 #include <asm/prom.h>
26 #include <asm/machdep.h>
27 #include <asm/cputable.h>
28 #include <asm/sections.h>
29 #include <asm/firmware.h>
30 #include <asm/vdso.h>
31 #include <asm/vdso_datapage.h>
32 #include <asm/setup.h>
33 
34 #undef DEBUG
35 
36 #ifdef DEBUG
37 #define DBG(fmt...) printk(fmt)
38 #else
39 #define DBG(fmt...)
40 #endif
41 
42 /* Max supported size for symbol names */
43 #define MAX_SYMNAME	64
44 
45 /* The alignment of the vDSO */
46 #define VDSO_ALIGNMENT	(1 << 16)
47 
48 static unsigned int vdso32_pages;
49 static void *vdso32_kbase;
50 static struct page **vdso32_pagelist;
51 unsigned long vdso32_sigtramp;
52 unsigned long vdso32_rt_sigtramp;
53 
54 #ifdef CONFIG_VDSO32
55 extern char vdso32_start, vdso32_end;
56 #endif
57 
58 #ifdef CONFIG_PPC64
59 extern char vdso64_start, vdso64_end;
60 static void *vdso64_kbase = &vdso64_start;
61 static unsigned int vdso64_pages;
62 static struct page **vdso64_pagelist;
63 unsigned long vdso64_rt_sigtramp;
64 #endif /* CONFIG_PPC64 */
65 
66 static int vdso_ready;
67 
68 /*
69  * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
70  * Once the early boot kernel code no longer needs to muck around
71  * with it, it will become dynamically allocated
72  */
73 static union {
74 	struct vdso_data	data;
75 	u8			page[PAGE_SIZE];
76 } vdso_data_store __page_aligned_data;
77 struct vdso_data *vdso_data = &vdso_data_store.data;
78 
79 /* Format of the patch table */
80 struct vdso_patch_def
81 {
82 	unsigned long	ftr_mask, ftr_value;
83 	const char	*gen_name;
84 	const char	*fix_name;
85 };
86 
87 /* Table of functions to patch based on the CPU type/revision
88  *
89  * Currently, we only change sync_dicache to do nothing on processors
90  * with a coherent icache
91  */
92 static struct vdso_patch_def vdso_patches[] = {
93 	{
94 		CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
95 		"__kernel_sync_dicache", "__kernel_sync_dicache_p5"
96 	},
97 };
98 
99 /*
100  * Some infos carried around for each of them during parsing at
101  * boot time.
102  */
103 struct lib32_elfinfo
104 {
105 	Elf32_Ehdr	*hdr;		/* ptr to ELF */
106 	Elf32_Sym	*dynsym;	/* ptr to .dynsym section */
107 	unsigned long	dynsymsize;	/* size of .dynsym section */
108 	char		*dynstr;	/* ptr to .dynstr section */
109 	unsigned long	text;		/* offset of .text section in .so */
110 };
111 
112 struct lib64_elfinfo
113 {
114 	Elf64_Ehdr	*hdr;
115 	Elf64_Sym	*dynsym;
116 	unsigned long	dynsymsize;
117 	char		*dynstr;
118 	unsigned long	text;
119 };
120 
121 
122 /*
123  * This is called from binfmt_elf, we create the special vma for the
124  * vDSO and insert it into the mm struct tree
125  */
126 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
127 {
128 	struct mm_struct *mm = current->mm;
129 	struct page **vdso_pagelist;
130 	unsigned long vdso_pages;
131 	unsigned long vdso_base;
132 	int rc;
133 
134 	if (!vdso_ready)
135 		return 0;
136 
137 #ifdef CONFIG_PPC64
138 	if (is_32bit_task()) {
139 		vdso_pagelist = vdso32_pagelist;
140 		vdso_pages = vdso32_pages;
141 		vdso_base = VDSO32_MBASE;
142 	} else {
143 		vdso_pagelist = vdso64_pagelist;
144 		vdso_pages = vdso64_pages;
145 		/*
146 		 * On 64bit we don't have a preferred map address. This
147 		 * allows get_unmapped_area to find an area near other mmaps
148 		 * and most likely share a SLB entry.
149 		 */
150 		vdso_base = 0;
151 	}
152 #else
153 	vdso_pagelist = vdso32_pagelist;
154 	vdso_pages = vdso32_pages;
155 	vdso_base = VDSO32_MBASE;
156 #endif
157 
158 	current->mm->context.vdso_base = 0;
159 
160 	/* vDSO has a problem and was disabled, just don't "enable" it for the
161 	 * process
162 	 */
163 	if (vdso_pages == 0)
164 		return 0;
165 	/* Add a page to the vdso size for the data page */
166 	vdso_pages ++;
167 
168 	/*
169 	 * pick a base address for the vDSO in process space. We try to put it
170 	 * at vdso_base which is the "natural" base for it, but we might fail
171 	 * and end up putting it elsewhere.
172 	 * Add enough to the size so that the result can be aligned.
173 	 */
174 	if (down_write_killable(&mm->mmap_sem))
175 		return -EINTR;
176 	vdso_base = get_unmapped_area(NULL, vdso_base,
177 				      (vdso_pages << PAGE_SHIFT) +
178 				      ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
179 				      0, 0);
180 	if (IS_ERR_VALUE(vdso_base)) {
181 		rc = vdso_base;
182 		goto fail_mmapsem;
183 	}
184 
185 	/* Add required alignment. */
186 	vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
187 
188 	/*
189 	 * Put vDSO base into mm struct. We need to do this before calling
190 	 * install_special_mapping or the perf counter mmap tracking code
191 	 * will fail to recognise it as a vDSO (since arch_vma_name fails).
192 	 */
193 	current->mm->context.vdso_base = vdso_base;
194 
195 	/*
196 	 * our vma flags don't have VM_WRITE so by default, the process isn't
197 	 * allowed to write those pages.
198 	 * gdb can break that with ptrace interface, and thus trigger COW on
199 	 * those pages but it's then your responsibility to never do that on
200 	 * the "data" page of the vDSO or you'll stop getting kernel updates
201 	 * and your nice userland gettimeofday will be totally dead.
202 	 * It's fine to use that for setting breakpoints in the vDSO code
203 	 * pages though.
204 	 */
205 	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
206 				     VM_READ|VM_EXEC|
207 				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
208 				     vdso_pagelist);
209 	if (rc) {
210 		current->mm->context.vdso_base = 0;
211 		goto fail_mmapsem;
212 	}
213 
214 	up_write(&mm->mmap_sem);
215 	return 0;
216 
217  fail_mmapsem:
218 	up_write(&mm->mmap_sem);
219 	return rc;
220 }
221 
222 const char *arch_vma_name(struct vm_area_struct *vma)
223 {
224 	if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
225 		return "[vdso]";
226 	return NULL;
227 }
228 
229 
230 
231 #ifdef CONFIG_VDSO32
232 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
233 				  unsigned long *size)
234 {
235 	Elf32_Shdr *sechdrs;
236 	unsigned int i;
237 	char *secnames;
238 
239 	/* Grab section headers and strings so we can tell who is who */
240 	sechdrs = (void *)ehdr + ehdr->e_shoff;
241 	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
242 
243 	/* Find the section they want */
244 	for (i = 1; i < ehdr->e_shnum; i++) {
245 		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
246 			if (size)
247 				*size = sechdrs[i].sh_size;
248 			return (void *)ehdr + sechdrs[i].sh_offset;
249 		}
250 	}
251 	*size = 0;
252 	return NULL;
253 }
254 
255 static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
256 					const char *symname)
257 {
258 	unsigned int i;
259 	char name[MAX_SYMNAME], *c;
260 
261 	for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
262 		if (lib->dynsym[i].st_name == 0)
263 			continue;
264 		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
265 			MAX_SYMNAME);
266 		c = strchr(name, '@');
267 		if (c)
268 			*c = 0;
269 		if (strcmp(symname, name) == 0)
270 			return &lib->dynsym[i];
271 	}
272 	return NULL;
273 }
274 
275 /* Note that we assume the section is .text and the symbol is relative to
276  * the library base
277  */
278 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
279 					    const char *symname)
280 {
281 	Elf32_Sym *sym = find_symbol32(lib, symname);
282 
283 	if (sym == NULL) {
284 		printk(KERN_WARNING "vDSO32: function %s not found !\n",
285 		       symname);
286 		return 0;
287 	}
288 	return sym->st_value - VDSO32_LBASE;
289 }
290 
291 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
292 				       struct lib64_elfinfo *v64,
293 				       const char *orig, const char *fix)
294 {
295 	Elf32_Sym *sym32_gen, *sym32_fix;
296 
297 	sym32_gen = find_symbol32(v32, orig);
298 	if (sym32_gen == NULL) {
299 		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
300 		return -1;
301 	}
302 	if (fix == NULL) {
303 		sym32_gen->st_name = 0;
304 		return 0;
305 	}
306 	sym32_fix = find_symbol32(v32, fix);
307 	if (sym32_fix == NULL) {
308 		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
309 		return -1;
310 	}
311 	sym32_gen->st_value = sym32_fix->st_value;
312 	sym32_gen->st_size = sym32_fix->st_size;
313 	sym32_gen->st_info = sym32_fix->st_info;
314 	sym32_gen->st_other = sym32_fix->st_other;
315 	sym32_gen->st_shndx = sym32_fix->st_shndx;
316 
317 	return 0;
318 }
319 #else /* !CONFIG_VDSO32 */
320 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
321 					    const char *symname)
322 {
323 	return 0;
324 }
325 
326 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
327 				       struct lib64_elfinfo *v64,
328 				       const char *orig, const char *fix)
329 {
330 	return 0;
331 }
332 #endif /* CONFIG_VDSO32 */
333 
334 
335 #ifdef CONFIG_PPC64
336 
337 static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
338 				  unsigned long *size)
339 {
340 	Elf64_Shdr *sechdrs;
341 	unsigned int i;
342 	char *secnames;
343 
344 	/* Grab section headers and strings so we can tell who is who */
345 	sechdrs = (void *)ehdr + ehdr->e_shoff;
346 	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
347 
348 	/* Find the section they want */
349 	for (i = 1; i < ehdr->e_shnum; i++) {
350 		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
351 			if (size)
352 				*size = sechdrs[i].sh_size;
353 			return (void *)ehdr + sechdrs[i].sh_offset;
354 		}
355 	}
356 	if (size)
357 		*size = 0;
358 	return NULL;
359 }
360 
361 static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
362 					const char *symname)
363 {
364 	unsigned int i;
365 	char name[MAX_SYMNAME], *c;
366 
367 	for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
368 		if (lib->dynsym[i].st_name == 0)
369 			continue;
370 		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
371 			MAX_SYMNAME);
372 		c = strchr(name, '@');
373 		if (c)
374 			*c = 0;
375 		if (strcmp(symname, name) == 0)
376 			return &lib->dynsym[i];
377 	}
378 	return NULL;
379 }
380 
381 /* Note that we assume the section is .text and the symbol is relative to
382  * the library base
383  */
384 static unsigned long __init find_function64(struct lib64_elfinfo *lib,
385 					    const char *symname)
386 {
387 	Elf64_Sym *sym = find_symbol64(lib, symname);
388 
389 	if (sym == NULL) {
390 		printk(KERN_WARNING "vDSO64: function %s not found !\n",
391 		       symname);
392 		return 0;
393 	}
394 	return sym->st_value - VDSO64_LBASE;
395 }
396 
397 static int __init vdso_do_func_patch64(struct lib32_elfinfo *v32,
398 				       struct lib64_elfinfo *v64,
399 				       const char *orig, const char *fix)
400 {
401 	Elf64_Sym *sym64_gen, *sym64_fix;
402 
403 	sym64_gen = find_symbol64(v64, orig);
404 	if (sym64_gen == NULL) {
405 		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
406 		return -1;
407 	}
408 	if (fix == NULL) {
409 		sym64_gen->st_name = 0;
410 		return 0;
411 	}
412 	sym64_fix = find_symbol64(v64, fix);
413 	if (sym64_fix == NULL) {
414 		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
415 		return -1;
416 	}
417 	sym64_gen->st_value = sym64_fix->st_value;
418 	sym64_gen->st_size = sym64_fix->st_size;
419 	sym64_gen->st_info = sym64_fix->st_info;
420 	sym64_gen->st_other = sym64_fix->st_other;
421 	sym64_gen->st_shndx = sym64_fix->st_shndx;
422 
423 	return 0;
424 }
425 
426 #endif /* CONFIG_PPC64 */
427 
428 
429 static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
430 					struct lib64_elfinfo *v64)
431 {
432 	void *sect;
433 
434 	/*
435 	 * Locate symbol tables & text section
436 	 */
437 
438 #ifdef CONFIG_VDSO32
439 	v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
440 	v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
441 	if (v32->dynsym == NULL || v32->dynstr == NULL) {
442 		printk(KERN_ERR "vDSO32: required symbol section not found\n");
443 		return -1;
444 	}
445 	sect = find_section32(v32->hdr, ".text", NULL);
446 	if (sect == NULL) {
447 		printk(KERN_ERR "vDSO32: the .text section was not found\n");
448 		return -1;
449 	}
450 	v32->text = sect - vdso32_kbase;
451 #endif
452 
453 #ifdef CONFIG_PPC64
454 	v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
455 	v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
456 	if (v64->dynsym == NULL || v64->dynstr == NULL) {
457 		printk(KERN_ERR "vDSO64: required symbol section not found\n");
458 		return -1;
459 	}
460 	sect = find_section64(v64->hdr, ".text", NULL);
461 	if (sect == NULL) {
462 		printk(KERN_ERR "vDSO64: the .text section was not found\n");
463 		return -1;
464 	}
465 	v64->text = sect - vdso64_kbase;
466 #endif /* CONFIG_PPC64 */
467 
468 	return 0;
469 }
470 
471 static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
472 					  struct lib64_elfinfo *v64)
473 {
474 	/*
475 	 * Find signal trampolines
476 	 */
477 
478 #ifdef CONFIG_PPC64
479 	vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
480 #endif
481 	vdso32_sigtramp	   = find_function32(v32, "__kernel_sigtramp32");
482 	vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
483 }
484 
485 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
486 				       struct lib64_elfinfo *v64)
487 {
488 #ifdef CONFIG_VDSO32
489 	Elf32_Sym *sym32;
490 #endif
491 #ifdef CONFIG_PPC64
492 	Elf64_Sym *sym64;
493 
494        	sym64 = find_symbol64(v64, "__kernel_datapage_offset");
495 	if (sym64 == NULL) {
496 		printk(KERN_ERR "vDSO64: Can't find symbol "
497 		       "__kernel_datapage_offset !\n");
498 		return -1;
499 	}
500 	*((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
501 		(vdso64_pages << PAGE_SHIFT) -
502 		(sym64->st_value - VDSO64_LBASE);
503 #endif /* CONFIG_PPC64 */
504 
505 #ifdef CONFIG_VDSO32
506 	sym32 = find_symbol32(v32, "__kernel_datapage_offset");
507 	if (sym32 == NULL) {
508 		printk(KERN_ERR "vDSO32: Can't find symbol "
509 		       "__kernel_datapage_offset !\n");
510 		return -1;
511 	}
512 	*((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
513 		(vdso32_pages << PAGE_SHIFT) -
514 		(sym32->st_value - VDSO32_LBASE);
515 #endif
516 
517 	return 0;
518 }
519 
520 
521 static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
522 				      struct lib64_elfinfo *v64)
523 {
524 	unsigned long size;
525 	void *start;
526 
527 #ifdef CONFIG_PPC64
528 	start = find_section64(v64->hdr, "__ftr_fixup", &size);
529 	if (start)
530 		do_feature_fixups(cur_cpu_spec->cpu_features,
531 				  start, start + size);
532 
533 	start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size);
534 	if (start)
535 		do_feature_fixups(cur_cpu_spec->mmu_features,
536 				  start, start + size);
537 
538 	start = find_section64(v64->hdr, "__fw_ftr_fixup", &size);
539 	if (start)
540 		do_feature_fixups(powerpc_firmware_features,
541 				  start, start + size);
542 
543 	start = find_section64(v64->hdr, "__lwsync_fixup", &size);
544 	if (start)
545 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
546 				 start, start + size);
547 #endif /* CONFIG_PPC64 */
548 
549 #ifdef CONFIG_VDSO32
550 	start = find_section32(v32->hdr, "__ftr_fixup", &size);
551 	if (start)
552 		do_feature_fixups(cur_cpu_spec->cpu_features,
553 				  start, start + size);
554 
555 	start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size);
556 	if (start)
557 		do_feature_fixups(cur_cpu_spec->mmu_features,
558 				  start, start + size);
559 
560 #ifdef CONFIG_PPC64
561 	start = find_section32(v32->hdr, "__fw_ftr_fixup", &size);
562 	if (start)
563 		do_feature_fixups(powerpc_firmware_features,
564 				  start, start + size);
565 #endif /* CONFIG_PPC64 */
566 
567 	start = find_section32(v32->hdr, "__lwsync_fixup", &size);
568 	if (start)
569 		do_lwsync_fixups(cur_cpu_spec->cpu_features,
570 				 start, start + size);
571 #endif
572 
573 	return 0;
574 }
575 
576 static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
577 				       struct lib64_elfinfo *v64)
578 {
579 	int i;
580 
581 	for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
582 		struct vdso_patch_def *patch = &vdso_patches[i];
583 		int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
584 			== patch->ftr_value;
585 		if (!match)
586 			continue;
587 
588 		DBG("replacing %s with %s...\n", patch->gen_name,
589 		    patch->fix_name ? "NONE" : patch->fix_name);
590 
591 		/*
592 		 * Patch the 32 bits and 64 bits symbols. Note that we do not
593 		 * patch the "." symbol on 64 bits.
594 		 * It would be easy to do, but doesn't seem to be necessary,
595 		 * patching the OPD symbol is enough.
596 		 */
597 		vdso_do_func_patch32(v32, v64, patch->gen_name,
598 				     patch->fix_name);
599 #ifdef CONFIG_PPC64
600 		vdso_do_func_patch64(v32, v64, patch->gen_name,
601 				     patch->fix_name);
602 #endif /* CONFIG_PPC64 */
603 	}
604 
605 	return 0;
606 }
607 
608 
609 static __init int vdso_setup(void)
610 {
611 	struct lib32_elfinfo	v32;
612 	struct lib64_elfinfo	v64;
613 
614 	v32.hdr = vdso32_kbase;
615 #ifdef CONFIG_PPC64
616 	v64.hdr = vdso64_kbase;
617 #endif
618 	if (vdso_do_find_sections(&v32, &v64))
619 		return -1;
620 
621 	if (vdso_fixup_datapage(&v32, &v64))
622 		return -1;
623 
624 	if (vdso_fixup_features(&v32, &v64))
625 		return -1;
626 
627 	if (vdso_fixup_alt_funcs(&v32, &v64))
628 		return -1;
629 
630 	vdso_setup_trampolines(&v32, &v64);
631 
632 	return 0;
633 }
634 
635 /*
636  * Called from setup_arch to initialize the bitmap of available
637  * syscalls in the systemcfg page
638  */
639 static void __init vdso_setup_syscall_map(void)
640 {
641 	unsigned int i;
642 	extern unsigned long *sys_call_table;
643 #ifdef CONFIG_PPC64
644 	extern unsigned long *compat_sys_call_table;
645 #endif
646 	extern unsigned long sys_ni_syscall;
647 
648 
649 	for (i = 0; i < NR_syscalls; i++) {
650 #ifdef CONFIG_PPC64
651 		if (sys_call_table[i] != sys_ni_syscall)
652 			vdso_data->syscall_map_64[i >> 5] |=
653 				0x80000000UL >> (i & 0x1f);
654 		if (IS_ENABLED(CONFIG_COMPAT) &&
655 		    compat_sys_call_table[i] != sys_ni_syscall)
656 			vdso_data->syscall_map_32[i >> 5] |=
657 				0x80000000UL >> (i & 0x1f);
658 #else /* CONFIG_PPC64 */
659 		if (sys_call_table[i] != sys_ni_syscall)
660 			vdso_data->syscall_map_32[i >> 5] |=
661 				0x80000000UL >> (i & 0x1f);
662 #endif /* CONFIG_PPC64 */
663 	}
664 }
665 
666 #ifdef CONFIG_PPC64
667 int vdso_getcpu_init(void)
668 {
669 	unsigned long cpu, node, val;
670 
671 	/*
672 	 * SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node
673 	 * in the next 16 bits.  The VDSO uses this to implement getcpu().
674 	 */
675 	cpu = get_cpu();
676 	WARN_ON_ONCE(cpu > 0xffff);
677 
678 	node = cpu_to_node(cpu);
679 	WARN_ON_ONCE(node > 0xffff);
680 
681 	val = (cpu & 0xfff) | ((node & 0xffff) << 16);
682 	mtspr(SPRN_SPRG_VDSO_WRITE, val);
683 	get_paca()->sprg_vdso = val;
684 
685 	put_cpu();
686 
687 	return 0;
688 }
689 /* We need to call this before SMP init */
690 early_initcall(vdso_getcpu_init);
691 #endif
692 
693 static int __init vdso_init(void)
694 {
695 	int i;
696 
697 #ifdef CONFIG_PPC64
698 	/*
699 	 * Fill up the "systemcfg" stuff for backward compatibility
700 	 */
701 	strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
702 	vdso_data->version.major = SYSTEMCFG_MAJOR;
703 	vdso_data->version.minor = SYSTEMCFG_MINOR;
704 	vdso_data->processor = mfspr(SPRN_PVR);
705 	/*
706 	 * Fake the old platform number for pSeries and add
707 	 * in LPAR bit if necessary
708 	 */
709 	vdso_data->platform = 0x100;
710 	if (firmware_has_feature(FW_FEATURE_LPAR))
711 		vdso_data->platform |= 1;
712 	vdso_data->physicalMemorySize = memblock_phys_mem_size();
713 	vdso_data->dcache_size = ppc64_caches.l1d.size;
714 	vdso_data->dcache_line_size = ppc64_caches.l1d.line_size;
715 	vdso_data->icache_size = ppc64_caches.l1i.size;
716 	vdso_data->icache_line_size = ppc64_caches.l1i.line_size;
717 	vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
718 	vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
719 	vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
720 	vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
721 
722 	/*
723 	 * Calculate the size of the 64 bits vDSO
724 	 */
725 	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
726 	DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
727 #endif /* CONFIG_PPC64 */
728 
729 
730 #ifdef CONFIG_VDSO32
731 	vdso32_kbase = &vdso32_start;
732 
733 	/*
734 	 * Calculate the size of the 32 bits vDSO
735 	 */
736 	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
737 	DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
738 #endif
739 
740 
741 	/*
742 	 * Setup the syscall map in the vDOS
743 	 */
744 	vdso_setup_syscall_map();
745 
746 	/*
747 	 * Initialize the vDSO images in memory, that is do necessary
748 	 * fixups of vDSO symbols, locate trampolines, etc...
749 	 */
750 	if (vdso_setup()) {
751 		printk(KERN_ERR "vDSO setup failure, not enabled !\n");
752 		vdso32_pages = 0;
753 #ifdef CONFIG_PPC64
754 		vdso64_pages = 0;
755 #endif
756 		return 0;
757 	}
758 
759 #ifdef CONFIG_VDSO32
760 	/* Make sure pages are in the correct state */
761 	vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *),
762 				  GFP_KERNEL);
763 	BUG_ON(vdso32_pagelist == NULL);
764 	for (i = 0; i < vdso32_pages; i++) {
765 		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
766 		get_page(pg);
767 		vdso32_pagelist[i] = pg;
768 	}
769 	vdso32_pagelist[i++] = virt_to_page(vdso_data);
770 	vdso32_pagelist[i] = NULL;
771 #endif
772 
773 #ifdef CONFIG_PPC64
774 	vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *),
775 				  GFP_KERNEL);
776 	BUG_ON(vdso64_pagelist == NULL);
777 	for (i = 0; i < vdso64_pages; i++) {
778 		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
779 		get_page(pg);
780 		vdso64_pagelist[i] = pg;
781 	}
782 	vdso64_pagelist[i++] = virt_to_page(vdso_data);
783 	vdso64_pagelist[i] = NULL;
784 #endif /* CONFIG_PPC64 */
785 
786 	get_page(virt_to_page(vdso_data));
787 
788 	smp_wmb();
789 	vdso_ready = 1;
790 
791 	return 0;
792 }
793 arch_initcall(vdso_init);
794