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v5.9
  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/processor.h>
 22#include <asm/mmu.h>
 23#include <asm/mmu_context.h>
 24#include <asm/prom.h>
 25#include <asm/machdep.h>
 26#include <asm/cputable.h>
 27#include <asm/sections.h>
 28#include <asm/firmware.h>
 29#include <asm/vdso.h>
 30#include <asm/vdso_datapage.h>
 31#include <asm/setup.h>
 32
 33#undef DEBUG
 34
 35#ifdef DEBUG
 36#define DBG(fmt...) printk(fmt)
 37#else
 38#define DBG(fmt...)
 39#endif
 40
 41/* Max supported size for symbol names */
 42#define MAX_SYMNAME	64
 43
 44/* The alignment of the vDSO */
 45#define VDSO_ALIGNMENT	(1 << 16)
 46
 47static unsigned int vdso32_pages;
 48static void *vdso32_kbase;
 49static struct page **vdso32_pagelist;
 50unsigned long vdso32_sigtramp;
 51unsigned long vdso32_rt_sigtramp;
 52
 53#ifdef CONFIG_VDSO32
 54extern char vdso32_start, vdso32_end;
 55#endif
 56
 57#ifdef CONFIG_PPC64
 58extern char vdso64_start, vdso64_end;
 59static void *vdso64_kbase = &vdso64_start;
 60static unsigned int vdso64_pages;
 61static struct page **vdso64_pagelist;
 62unsigned long vdso64_rt_sigtramp;
 63#endif /* CONFIG_PPC64 */
 64
 65static int vdso_ready;
 66
 67/*
 68 * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
 69 * Once the early boot kernel code no longer needs to muck around
 70 * with it, it will become dynamically allocated
 71 */
 72static union {
 73	struct vdso_data	data;
 74	u8			page[PAGE_SIZE];
 75} vdso_data_store __page_aligned_data;
 76struct vdso_data *vdso_data = &vdso_data_store.data;
 77
 78/* Format of the patch table */
 79struct vdso_patch_def
 80{
 81	unsigned long	ftr_mask, ftr_value;
 82	const char	*gen_name;
 83	const char	*fix_name;
 84};
 85
 86/* Table of functions to patch based on the CPU type/revision
 87 *
 88 * Currently, we only change sync_dicache to do nothing on processors
 89 * with a coherent icache
 90 */
 91static struct vdso_patch_def vdso_patches[] = {
 92	{
 93		CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
 94		"__kernel_sync_dicache", "__kernel_sync_dicache_p5"
 95	},
 96};
 97
 98/*
 99 * Some infos carried around for each of them during parsing at
100 * boot time.
101 */
102struct lib32_elfinfo
103{
104	Elf32_Ehdr	*hdr;		/* ptr to ELF */
105	Elf32_Sym	*dynsym;	/* ptr to .dynsym section */
106	unsigned long	dynsymsize;	/* size of .dynsym section */
107	char		*dynstr;	/* ptr to .dynstr section */
108	unsigned long	text;		/* offset of .text section in .so */
109};
110
111struct lib64_elfinfo
 
112{
113	Elf64_Ehdr	*hdr;
114	Elf64_Sym	*dynsym;
115	unsigned long	dynsymsize;
116	char		*dynstr;
117	unsigned long	text;
118};
119
120
121/*
122 * This is called from binfmt_elf, we create the special vma for the
123 * vDSO and insert it into the mm struct tree
124 */
125int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
126{
127	struct mm_struct *mm = current->mm;
128	struct page **vdso_pagelist;
129	unsigned long vdso_pages;
130	unsigned long vdso_base;
131	int rc;
132
133	if (!vdso_ready)
134		return 0;
135
136#ifdef CONFIG_PPC64
137	if (is_32bit_task()) {
138		vdso_pagelist = vdso32_pagelist;
139		vdso_pages = vdso32_pages;
140		vdso_base = VDSO32_MBASE;
141	} else {
142		vdso_pagelist = vdso64_pagelist;
143		vdso_pages = vdso64_pages;
144		/*
145		 * On 64bit we don't have a preferred map address. This
146		 * allows get_unmapped_area to find an area near other mmaps
147		 * and most likely share a SLB entry.
148		 */
149		vdso_base = 0;
150	}
151#else
152	vdso_pagelist = vdso32_pagelist;
153	vdso_pages = vdso32_pages;
154	vdso_base = VDSO32_MBASE;
155#endif
156
157	current->mm->context.vdso_base = 0;
158
159	/* vDSO has a problem and was disabled, just don't "enable" it for the
160	 * process
161	 */
162	if (vdso_pages == 0)
163		return 0;
164	/* Add a page to the vdso size for the data page */
165	vdso_pages ++;
166
167	/*
168	 * pick a base address for the vDSO in process space. We try to put it
169	 * at vdso_base which is the "natural" base for it, but we might fail
170	 * and end up putting it elsewhere.
171	 * Add enough to the size so that the result can be aligned.
172	 */
173	if (mmap_write_lock_killable(mm))
174		return -EINTR;
175	vdso_base = get_unmapped_area(NULL, vdso_base,
176				      (vdso_pages << PAGE_SHIFT) +
177				      ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
178				      0, 0);
179	if (IS_ERR_VALUE(vdso_base)) {
180		rc = vdso_base;
181		goto fail_mmapsem;
182	}
183
184	/* Add required alignment. */
185	vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
186
187	/*
188	 * Put vDSO base into mm struct. We need to do this before calling
189	 * install_special_mapping or the perf counter mmap tracking code
190	 * will fail to recognise it as a vDSO (since arch_vma_name fails).
191	 */
192	current->mm->context.vdso_base = vdso_base;
193
194	/*
195	 * our vma flags don't have VM_WRITE so by default, the process isn't
196	 * allowed to write those pages.
197	 * gdb can break that with ptrace interface, and thus trigger COW on
198	 * those pages but it's then your responsibility to never do that on
199	 * the "data" page of the vDSO or you'll stop getting kernel updates
200	 * and your nice userland gettimeofday will be totally dead.
201	 * It's fine to use that for setting breakpoints in the vDSO code
202	 * pages though.
203	 */
204	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
205				     VM_READ|VM_EXEC|
206				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
207				     vdso_pagelist);
208	if (rc) {
209		current->mm->context.vdso_base = 0;
210		goto fail_mmapsem;
211	}
212
213	mmap_write_unlock(mm);
214	return 0;
 
215
216 fail_mmapsem:
217	mmap_write_unlock(mm);
218	return rc;
219}
220
221const char *arch_vma_name(struct vm_area_struct *vma)
222{
223	if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
224		return "[vdso]";
225	return NULL;
226}
227
 
 
228
 
 
 
 
229
230#ifdef CONFIG_VDSO32
231static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
232				  unsigned long *size)
233{
234	Elf32_Shdr *sechdrs;
235	unsigned int i;
236	char *secnames;
237
238	/* Grab section headers and strings so we can tell who is who */
239	sechdrs = (void *)ehdr + ehdr->e_shoff;
240	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
241
242	/* Find the section they want */
243	for (i = 1; i < ehdr->e_shnum; i++) {
244		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
245			if (size)
246				*size = sechdrs[i].sh_size;
247			return (void *)ehdr + sechdrs[i].sh_offset;
248		}
249	}
250	*size = 0;
251	return NULL;
252}
253
254static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
255					const char *symname)
256{
257	unsigned int i;
258	char name[MAX_SYMNAME], *c;
259
260	for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
261		if (lib->dynsym[i].st_name == 0)
262			continue;
263		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
264			MAX_SYMNAME);
265		c = strchr(name, '@');
266		if (c)
267			*c = 0;
268		if (strcmp(symname, name) == 0)
269			return &lib->dynsym[i];
270	}
271	return NULL;
272}
273
274/* Note that we assume the section is .text and the symbol is relative to
275 * the library base
 
 
 
 
276 */
277static unsigned long __init find_function32(struct lib32_elfinfo *lib,
278					    const char *symname)
279{
280	Elf32_Sym *sym = find_symbol32(lib, symname);
 
281
282	if (sym == NULL) {
283		printk(KERN_WARNING "vDSO32: function %s not found !\n",
284		       symname);
285		return 0;
286	}
287	return sym->st_value - VDSO32_LBASE;
288}
289
290static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
291				       struct lib64_elfinfo *v64,
292				       const char *orig, const char *fix)
293{
294	Elf32_Sym *sym32_gen, *sym32_fix;
295
296	sym32_gen = find_symbol32(v32, orig);
297	if (sym32_gen == NULL) {
298		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
299		return -1;
300	}
301	if (fix == NULL) {
302		sym32_gen->st_name = 0;
303		return 0;
304	}
305	sym32_fix = find_symbol32(v32, fix);
306	if (sym32_fix == NULL) {
307		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
308		return -1;
309	}
310	sym32_gen->st_value = sym32_fix->st_value;
311	sym32_gen->st_size = sym32_fix->st_size;
312	sym32_gen->st_info = sym32_fix->st_info;
313	sym32_gen->st_other = sym32_fix->st_other;
314	sym32_gen->st_shndx = sym32_fix->st_shndx;
315
316	return 0;
317}
318#else /* !CONFIG_VDSO32 */
319static unsigned long __init find_function32(struct lib32_elfinfo *lib,
320					    const char *symname)
321{
322	return 0;
323}
324
325static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
326				       struct lib64_elfinfo *v64,
327				       const char *orig, const char *fix)
328{
329	return 0;
330}
331#endif /* CONFIG_VDSO32 */
332
333
334#ifdef CONFIG_PPC64
335
336static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
337				  unsigned long *size)
338{
339	Elf64_Shdr *sechdrs;
340	unsigned int i;
341	char *secnames;
342
343	/* Grab section headers and strings so we can tell who is who */
344	sechdrs = (void *)ehdr + ehdr->e_shoff;
345	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
346
347	/* Find the section they want */
348	for (i = 1; i < ehdr->e_shnum; i++) {
349		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
350			if (size)
351				*size = sechdrs[i].sh_size;
352			return (void *)ehdr + sechdrs[i].sh_offset;
353		}
354	}
355	if (size)
356		*size = 0;
357	return NULL;
358}
359
360static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
361					const char *symname)
362{
363	unsigned int i;
364	char name[MAX_SYMNAME], *c;
365
366	for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
367		if (lib->dynsym[i].st_name == 0)
368			continue;
369		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
370			MAX_SYMNAME);
371		c = strchr(name, '@');
372		if (c)
373			*c = 0;
374		if (strcmp(symname, name) == 0)
375			return &lib->dynsym[i];
376	}
377	return NULL;
378}
 
379
380/* Note that we assume the section is .text and the symbol is relative to
381 * the library base
382 */
383static unsigned long __init find_function64(struct lib64_elfinfo *lib,
384					    const char *symname)
385{
386	Elf64_Sym *sym = find_symbol64(lib, symname);
 
387
388	if (sym == NULL) {
389		printk(KERN_WARNING "vDSO64: function %s not found !\n",
390		       symname);
391		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
392	}
393	return sym->st_value - VDSO64_LBASE;
 
394}
395
396static int __init vdso_do_func_patch64(struct lib32_elfinfo *v32,
397				       struct lib64_elfinfo *v64,
398				       const char *orig, const char *fix)
 
 
399{
400	Elf64_Sym *sym64_gen, *sym64_fix;
 
 
 
 
401
402	sym64_gen = find_symbol64(v64, orig);
403	if (sym64_gen == NULL) {
404		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
405		return -1;
406	}
407	if (fix == NULL) {
408		sym64_gen->st_name = 0;
409		return 0;
410	}
411	sym64_fix = find_symbol64(v64, fix);
412	if (sym64_fix == NULL) {
413		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
414		return -1;
415	}
416	sym64_gen->st_value = sym64_fix->st_value;
417	sym64_gen->st_size = sym64_fix->st_size;
418	sym64_gen->st_info = sym64_fix->st_info;
419	sym64_gen->st_other = sym64_fix->st_other;
420	sym64_gen->st_shndx = sym64_fix->st_shndx;
421
422	return 0;
423}
424
425#endif /* CONFIG_PPC64 */
426
 
 
 
 
 
 
 
 
 
427
428static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
429					struct lib64_elfinfo *v64)
430{
431	void *sect;
432
433	/*
434	 * Locate symbol tables & text section
 
 
435	 */
 
436
437#ifdef CONFIG_VDSO32
438	v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
439	v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
440	if (v32->dynsym == NULL || v32->dynstr == NULL) {
441		printk(KERN_ERR "vDSO32: required symbol section not found\n");
442		return -1;
443	}
444	sect = find_section32(v32->hdr, ".text", NULL);
445	if (sect == NULL) {
446		printk(KERN_ERR "vDSO32: the .text section was not found\n");
447		return -1;
448	}
449	v32->text = sect - vdso32_kbase;
450#endif
451
452#ifdef CONFIG_PPC64
453	v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
454	v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
455	if (v64->dynsym == NULL || v64->dynstr == NULL) {
456		printk(KERN_ERR "vDSO64: required symbol section not found\n");
457		return -1;
458	}
459	sect = find_section64(v64->hdr, ".text", NULL);
460	if (sect == NULL) {
461		printk(KERN_ERR "vDSO64: the .text section was not found\n");
462		return -1;
463	}
464	v64->text = sect - vdso64_kbase;
465#endif /* CONFIG_PPC64 */
466
467	return 0;
468}
469
470static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
471					  struct lib64_elfinfo *v64)
472{
473	/*
474	 * Find signal trampolines
 
 
 
 
 
 
 
475	 */
 
 
 
 
 
476
477#ifdef CONFIG_PPC64
478	vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
479#endif
480	vdso32_sigtramp	   = find_function32(v32, "__kernel_sigtramp32");
481	vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
482}
483
484static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
485				       struct lib64_elfinfo *v64)
486{
487#ifdef CONFIG_VDSO32
488	Elf32_Sym *sym32;
489#endif
490#ifdef CONFIG_PPC64
491	Elf64_Sym *sym64;
492
493       	sym64 = find_symbol64(v64, "__kernel_datapage_offset");
494	if (sym64 == NULL) {
495		printk(KERN_ERR "vDSO64: Can't find symbol "
496		       "__kernel_datapage_offset !\n");
497		return -1;
498	}
499	*((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
500		(vdso64_pages << PAGE_SHIFT) -
501		(sym64->st_value - VDSO64_LBASE);
502#endif /* CONFIG_PPC64 */
503
504#ifdef CONFIG_VDSO32
505	sym32 = find_symbol32(v32, "__kernel_datapage_offset");
506	if (sym32 == NULL) {
507		printk(KERN_ERR "vDSO32: Can't find symbol "
508		       "__kernel_datapage_offset !\n");
509		return -1;
510	}
511	*((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
512		(vdso32_pages << PAGE_SHIFT) -
513		(sym32->st_value - VDSO32_LBASE);
514#endif
515
516	return 0;
517}
 
518
 
 
 
519
520static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
521				      struct lib64_elfinfo *v64)
 
 
 
 
 
 
522{
523	unsigned long size;
524	void *start;
525
526#ifdef CONFIG_PPC64
527	start = find_section64(v64->hdr, "__ftr_fixup", &size);
528	if (start)
529		do_feature_fixups(cur_cpu_spec->cpu_features,
530				  start, start + size);
531
532	start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size);
533	if (start)
534		do_feature_fixups(cur_cpu_spec->mmu_features,
535				  start, start + size);
536
537	start = find_section64(v64->hdr, "__fw_ftr_fixup", &size);
538	if (start)
539		do_feature_fixups(powerpc_firmware_features,
540				  start, start + size);
541
542	start = find_section64(v64->hdr, "__lwsync_fixup", &size);
543	if (start)
544		do_lwsync_fixups(cur_cpu_spec->cpu_features,
545				 start, start + size);
546#endif /* CONFIG_PPC64 */
547
548#ifdef CONFIG_VDSO32
549	start = find_section32(v32->hdr, "__ftr_fixup", &size);
550	if (start)
551		do_feature_fixups(cur_cpu_spec->cpu_features,
552				  start, start + size);
553
554	start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size);
555	if (start)
556		do_feature_fixups(cur_cpu_spec->mmu_features,
557				  start, start + size);
558
559#ifdef CONFIG_PPC64
560	start = find_section32(v32->hdr, "__fw_ftr_fixup", &size);
561	if (start)
562		do_feature_fixups(powerpc_firmware_features,
563				  start, start + size);
564#endif /* CONFIG_PPC64 */
565
566	start = find_section32(v32->hdr, "__lwsync_fixup", &size);
567	if (start)
568		do_lwsync_fixups(cur_cpu_spec->cpu_features,
569				 start, start + size);
570#endif
571
572	return 0;
573}
574
575static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
576				       struct lib64_elfinfo *v64)
577{
578	int i;
579
580	for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
581		struct vdso_patch_def *patch = &vdso_patches[i];
582		int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
583			== patch->ftr_value;
584		if (!match)
585			continue;
586
587		DBG("replacing %s with %s...\n", patch->gen_name,
588		    patch->fix_name ? "NONE" : patch->fix_name);
589
590		/*
591		 * Patch the 32 bits and 64 bits symbols. Note that we do not
592		 * patch the "." symbol on 64 bits.
593		 * It would be easy to do, but doesn't seem to be necessary,
594		 * patching the OPD symbol is enough.
595		 */
596		vdso_do_func_patch32(v32, v64, patch->gen_name,
597				     patch->fix_name);
598#ifdef CONFIG_PPC64
599		vdso_do_func_patch64(v32, v64, patch->gen_name,
600				     patch->fix_name);
601#endif /* CONFIG_PPC64 */
602	}
603
604	return 0;
605}
606
607
608static __init int vdso_setup(void)
609{
610	struct lib32_elfinfo	v32;
611	struct lib64_elfinfo	v64;
612
613	v32.hdr = vdso32_kbase;
614#ifdef CONFIG_PPC64
615	v64.hdr = vdso64_kbase;
616#endif
617	if (vdso_do_find_sections(&v32, &v64))
618		return -1;
619
620	if (vdso_fixup_datapage(&v32, &v64))
621		return -1;
622
623	if (vdso_fixup_features(&v32, &v64))
624		return -1;
625
626	if (vdso_fixup_alt_funcs(&v32, &v64))
627		return -1;
628
629	vdso_setup_trampolines(&v32, &v64);
630
631	return 0;
632}
633
634/*
635 * Called from setup_arch to initialize the bitmap of available
636 * syscalls in the systemcfg page
637 */
638static void __init vdso_setup_syscall_map(void)
639{
640	unsigned int i;
641	extern unsigned long *sys_call_table;
642#ifdef CONFIG_PPC64
643	extern unsigned long *compat_sys_call_table;
644#endif
645	extern unsigned long sys_ni_syscall;
646
647
648	for (i = 0; i < NR_syscalls; i++) {
649#ifdef CONFIG_PPC64
650		if (sys_call_table[i] != sys_ni_syscall)
651			vdso_data->syscall_map_64[i >> 5] |=
652				0x80000000UL >> (i & 0x1f);
653		if (IS_ENABLED(CONFIG_COMPAT) &&
654		    compat_sys_call_table[i] != sys_ni_syscall)
655			vdso_data->syscall_map_32[i >> 5] |=
656				0x80000000UL >> (i & 0x1f);
657#else /* CONFIG_PPC64 */
658		if (sys_call_table[i] != sys_ni_syscall)
659			vdso_data->syscall_map_32[i >> 5] |=
660				0x80000000UL >> (i & 0x1f);
661#endif /* CONFIG_PPC64 */
662	}
663}
664
665#ifdef CONFIG_PPC64
666int vdso_getcpu_init(void)
667{
668	unsigned long cpu, node, val;
669
670	/*
671	 * SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node
672	 * in the next 16 bits.  The VDSO uses this to implement getcpu().
673	 */
674	cpu = get_cpu();
675	WARN_ON_ONCE(cpu > 0xffff);
676
677	node = cpu_to_node(cpu);
678	WARN_ON_ONCE(node > 0xffff);
679
680	val = (cpu & 0xffff) | ((node & 0xffff) << 16);
681	mtspr(SPRN_SPRG_VDSO_WRITE, val);
682	get_paca()->sprg_vdso = val;
683
684	put_cpu();
685
686	return 0;
687}
688/* We need to call this before SMP init */
689early_initcall(vdso_getcpu_init);
690#endif
691
692static int __init vdso_init(void)
693{
694	int i;
 
 
 
 
 
 
695
 
 
 
 
 
 
 
 
696#ifdef CONFIG_PPC64
697	/*
698	 * Fill up the "systemcfg" stuff for backward compatibility
699	 */
700	strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
701	vdso_data->version.major = SYSTEMCFG_MAJOR;
702	vdso_data->version.minor = SYSTEMCFG_MINOR;
703	vdso_data->processor = mfspr(SPRN_PVR);
704	/*
705	 * Fake the old platform number for pSeries and add
706	 * in LPAR bit if necessary
707	 */
708	vdso_data->platform = 0x100;
709	if (firmware_has_feature(FW_FEATURE_LPAR))
710		vdso_data->platform |= 1;
711	vdso_data->physicalMemorySize = memblock_phys_mem_size();
712	vdso_data->dcache_size = ppc64_caches.l1d.size;
713	vdso_data->dcache_line_size = ppc64_caches.l1d.line_size;
714	vdso_data->icache_size = ppc64_caches.l1i.size;
715	vdso_data->icache_line_size = ppc64_caches.l1i.line_size;
716	vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
717	vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
718	vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
719	vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
720
721	/*
722	 * Calculate the size of the 64 bits vDSO
723	 */
724	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
725	DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
726#endif /* CONFIG_PPC64 */
727
728
729#ifdef CONFIG_VDSO32
730	vdso32_kbase = &vdso32_start;
731
732	/*
733	 * Calculate the size of the 32 bits vDSO
734	 */
735	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
736	DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
737#endif
738
739
740	/*
741	 * Setup the syscall map in the vDOS
742	 */
743	vdso_setup_syscall_map();
744
745	/*
746	 * Initialize the vDSO images in memory, that is do necessary
747	 * fixups of vDSO symbols, locate trampolines, etc...
748	 */
749	if (vdso_setup()) {
750		printk(KERN_ERR "vDSO setup failure, not enabled !\n");
751		vdso32_pages = 0;
752#ifdef CONFIG_PPC64
753		vdso64_pages = 0;
754#endif
755		return 0;
756	}
757
758#ifdef CONFIG_VDSO32
759	/* Make sure pages are in the correct state */
760	vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *),
761				  GFP_KERNEL);
762	BUG_ON(vdso32_pagelist == NULL);
763	for (i = 0; i < vdso32_pages; i++) {
764		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
765		get_page(pg);
766		vdso32_pagelist[i] = pg;
767	}
768	vdso32_pagelist[i++] = virt_to_page(vdso_data);
769	vdso32_pagelist[i] = NULL;
770#endif
771
772#ifdef CONFIG_PPC64
773	vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *),
774				  GFP_KERNEL);
775	BUG_ON(vdso64_pagelist == NULL);
776	for (i = 0; i < vdso64_pages; i++) {
777		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
778		get_page(pg);
779		vdso64_pagelist[i] = pg;
780	}
781	vdso64_pagelist[i++] = virt_to_page(vdso_data);
782	vdso64_pagelist[i] = NULL;
783#endif /* CONFIG_PPC64 */
784
785	get_page(virt_to_page(vdso_data));
 
786
787	smp_wmb();
788	vdso_ready = 1;
789
790	return 0;
791}
792arch_initcall(vdso_init);
v5.14.15
  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#include <linux/syscalls.h>
 21#include <linux/time_namespace.h>
 22#include <vdso/datapage.h>
 23
 24#include <asm/syscall.h>
 25#include <asm/processor.h>
 26#include <asm/mmu.h>
 27#include <asm/mmu_context.h>
 28#include <asm/prom.h>
 29#include <asm/machdep.h>
 30#include <asm/cputable.h>
 31#include <asm/sections.h>
 32#include <asm/firmware.h>
 33#include <asm/vdso.h>
 34#include <asm/vdso_datapage.h>
 35#include <asm/setup.h>
 36
 
 
 
 
 
 
 
 
 
 
 
 37/* The alignment of the vDSO */
 38#define VDSO_ALIGNMENT	(1 << 16)
 39
 
 
 
 
 
 
 
 40extern char vdso32_start, vdso32_end;
 
 
 
 41extern char vdso64_start, vdso64_end;
 
 
 
 
 
 
 
 42
 43/*
 44 * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
 45 * Once the early boot kernel code no longer needs to muck around
 46 * with it, it will become dynamically allocated
 47 */
 48static union {
 49	struct vdso_arch_data	data;
 50	u8			page[PAGE_SIZE];
 51} vdso_data_store __page_aligned_data;
 52struct vdso_arch_data *vdso_data = &vdso_data_store.data;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 53
 54enum vvar_pages {
 55	VVAR_DATA_PAGE_OFFSET,
 56	VVAR_TIMENS_PAGE_OFFSET,
 57	VVAR_NR_PAGES,
 
 
 
 
 
 
 
 58};
 59
 60static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma,
 61		       unsigned long text_size)
 62{
 63	unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 64
 65	if (new_size != text_size)
 66		return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 67
 68	current->mm->context.vdso = (void __user *)new_vma->vm_start;
 
 
 
 
 
 
 
 
 69
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 70	return 0;
 71}
 72
 73static int vdso32_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
 74{
 75	return vdso_mremap(sm, new_vma, &vdso32_end - &vdso32_start);
 76}
 77
 78static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
 79{
 80	return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
 
 
 81}
 82
 83static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 84			     struct vm_area_struct *vma, struct vm_fault *vmf);
 85
 86static struct vm_special_mapping vvar_spec __ro_after_init = {
 87	.name = "[vvar]",
 88	.fault = vvar_fault,
 89};
 90
 91static struct vm_special_mapping vdso32_spec __ro_after_init = {
 92	.name = "[vdso]",
 93	.mremap = vdso32_mremap,
 94};
 
 
 
 95
 96static struct vm_special_mapping vdso64_spec __ro_after_init = {
 97	.name = "[vdso]",
 98	.mremap = vdso64_mremap,
 99};
 
 
 
 
 
 
 
 
 
 
 
100
101#ifdef CONFIG_TIME_NS
102struct vdso_data *arch_get_vdso_data(void *vvar_page)
103{
104	return ((struct vdso_arch_data *)vvar_page)->data;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
105}
106
107/*
108 * The vvar mapping contains data for a specific time namespace, so when a task
109 * changes namespace we must unmap its vvar data for the old namespace.
110 * Subsequent faults will map in data for the new namespace.
111 *
112 * For more details see timens_setup_vdso_data().
113 */
114int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
 
115{
116	struct mm_struct *mm = task->mm;
117	struct vm_area_struct *vma;
118
119	mmap_read_lock(mm);
 
 
 
 
 
 
120
121	for (vma = mm->mmap; vma; vma = vma->vm_next) {
122		unsigned long size = vma->vm_end - vma->vm_start;
 
 
 
123
124		if (vma_is_special_mapping(vma, &vvar_spec))
125			zap_page_range(vma, vma->vm_start, size);
 
 
 
 
 
 
 
 
 
 
 
126	}
 
 
 
 
 
127
128	mmap_read_unlock(mm);
 
 
 
 
 
129	return 0;
130}
131
132static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
 
 
133{
134	if (likely(vma->vm_mm == current->mm))
135		return current->nsproxy->time_ns->vvar_page;
 
 
136
137	/*
138	 * VM_PFNMAP | VM_IO protect .fault() handler from being called
139	 * through interfaces like /proc/$pid/mem or
140	 * process_vm_{readv,writev}() as long as there's no .access()
141	 * in special_mapping_vmops.
142	 * For more details check_vma_flags() and __access_remote_vm()
143	 */
144	WARN(1, "vvar_page accessed remotely");
145
 
 
 
 
 
 
 
 
 
 
 
 
 
 
146	return NULL;
147}
148#else
149static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
 
150{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
151	return NULL;
152}
153#endif
154
155static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
156			     struct vm_area_struct *vma, struct vm_fault *vmf)
 
 
 
157{
158	struct page *timens_page = find_timens_vvar_page(vma);
159	unsigned long pfn;
160
161	switch (vmf->pgoff) {
162	case VVAR_DATA_PAGE_OFFSET:
163		if (timens_page)
164			pfn = page_to_pfn(timens_page);
165		else
166			pfn = virt_to_pfn(vdso_data);
167		break;
168#ifdef CONFIG_TIME_NS
169	case VVAR_TIMENS_PAGE_OFFSET:
170		/*
171		 * If a task belongs to a time namespace then a namespace
172		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
173		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
174		 * offset.
175		 * See also the comment near timens_setup_vdso_data().
176		 */
177		if (!timens_page)
178			return VM_FAULT_SIGBUS;
179		pfn = virt_to_pfn(vdso_data);
180		break;
181#endif /* CONFIG_TIME_NS */
182	default:
183		return VM_FAULT_SIGBUS;
184	}
185
186	return vmf_insert_pfn(vma, vmf->address, pfn);
187}
188
189/*
190 * This is called from binfmt_elf, we create the special vma for the
191 * vDSO and insert it into the mm struct tree
192 */
193static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
194{
195	unsigned long vdso_size, vdso_base, mappings_size;
196	struct vm_special_mapping *vdso_spec;
197	unsigned long vvar_size = VVAR_NR_PAGES * PAGE_SIZE;
198	struct mm_struct *mm = current->mm;
199	struct vm_area_struct *vma;
200
201	if (is_32bit_task()) {
202		vdso_spec = &vdso32_spec;
203		vdso_size = &vdso32_end - &vdso32_start;
204		vdso_base = VDSO32_MBASE;
205	} else {
206		vdso_spec = &vdso64_spec;
207		vdso_size = &vdso64_end - &vdso64_start;
208		/*
209		 * On 64bit we don't have a preferred map address. This
210		 * allows get_unmapped_area to find an area near other mmaps
211		 * and most likely share a SLB entry.
212		 */
213		vdso_base = 0;
214	}
 
 
 
 
 
215
216	mappings_size = vdso_size + vvar_size;
217	mappings_size += (VDSO_ALIGNMENT - 1) & PAGE_MASK;
 
 
218
219	/*
220	 * pick a base address for the vDSO in process space. We try to put it
221	 * at vdso_base which is the "natural" base for it, but we might fail
222	 * and end up putting it elsewhere.
223	 * Add enough to the size so that the result can be aligned.
224	 */
225	vdso_base = get_unmapped_area(NULL, vdso_base, mappings_size, 0, 0);
226	if (IS_ERR_VALUE(vdso_base))
227		return vdso_base;
228
229	/* Add required alignment. */
230	vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
 
 
231
232	/*
233	 * Put vDSO base into mm struct. We need to do this before calling
234	 * install_special_mapping or the perf counter mmap tracking code
235	 * will fail to recognise it as a vDSO.
236	 */
237	mm->context.vdso = (void __user *)vdso_base + vvar_size;
238
239	vma = _install_special_mapping(mm, vdso_base, vvar_size,
240				       VM_READ | VM_MAYREAD | VM_IO |
241				       VM_DONTDUMP | VM_PFNMAP, &vvar_spec);
242	if (IS_ERR(vma))
243		return PTR_ERR(vma);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
244
 
 
 
 
 
 
245	/*
246	 * our vma flags don't have VM_WRITE so by default, the process isn't
247	 * allowed to write those pages.
248	 * gdb can break that with ptrace interface, and thus trigger COW on
249	 * those pages but it's then your responsibility to never do that on
250	 * the "data" page of the vDSO or you'll stop getting kernel updates
251	 * and your nice userland gettimeofday will be totally dead.
252	 * It's fine to use that for setting breakpoints in the vDSO code
253	 * pages though.
254	 */
255	vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size,
256				       VM_READ | VM_EXEC | VM_MAYREAD |
257				       VM_MAYWRITE | VM_MAYEXEC, vdso_spec);
258	if (IS_ERR(vma))
259		do_munmap(mm, vdso_base, vvar_size, NULL);
260
261	return PTR_ERR_OR_ZERO(vma);
 
 
 
 
262}
263
264int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
265{
266	struct mm_struct *mm = current->mm;
267	int rc;
 
 
 
268
269	mm->context.vdso = NULL;
 
 
 
 
 
 
 
 
 
270
271	if (mmap_write_lock_killable(mm))
272		return -EINTR;
 
 
 
 
 
 
 
 
 
273
274	rc = __arch_setup_additional_pages(bprm, uses_interp);
275	if (rc)
276		mm->context.vdso = NULL;
277
278	mmap_write_unlock(mm);
279	return rc;
280}
281
282#define VDSO_DO_FIXUPS(type, value, bits, sec) do {					\
283	void *__start = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_start);	\
284	void *__end = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_end);	\
285											\
286	do_##type##_fixups((value), __start, __end);					\
287} while (0)
288
289static void __init vdso_fixup_features(void)
290{
 
 
 
291#ifdef CONFIG_PPC64
292	VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 64, ftr_fixup);
293	VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 64, mmu_ftr_fixup);
294	VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 64, fw_ftr_fixup);
295	VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 64, lwsync_fixup);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
296#endif /* CONFIG_PPC64 */
297
298#ifdef CONFIG_VDSO32
299	VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 32, ftr_fixup);
300	VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 32, mmu_ftr_fixup);
 
 
 
 
 
 
 
 
301#ifdef CONFIG_PPC64
302	VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 32, fw_ftr_fixup);
 
 
 
303#endif /* CONFIG_PPC64 */
304	VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 32, lwsync_fixup);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
305#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
306}
307
308/*
309 * Called from setup_arch to initialize the bitmap of available
310 * syscalls in the systemcfg page
311 */
312static void __init vdso_setup_syscall_map(void)
313{
314	unsigned int i;
 
 
 
 
 
 
315
316	for (i = 0; i < NR_syscalls; i++) {
317		if (sys_call_table[i] != (unsigned long)&sys_ni_syscall)
318			vdso_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
 
 
319		if (IS_ENABLED(CONFIG_COMPAT) &&
320		    compat_sys_call_table[i] != (unsigned long)&sys_ni_syscall)
321			vdso_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
 
 
 
 
 
 
322	}
323}
324
325#ifdef CONFIG_PPC64
326int vdso_getcpu_init(void)
327{
328	unsigned long cpu, node, val;
329
330	/*
331	 * SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node
332	 * in the next 16 bits.  The VDSO uses this to implement getcpu().
333	 */
334	cpu = get_cpu();
335	WARN_ON_ONCE(cpu > 0xffff);
336
337	node = cpu_to_node(cpu);
338	WARN_ON_ONCE(node > 0xffff);
339
340	val = (cpu & 0xffff) | ((node & 0xffff) << 16);
341	mtspr(SPRN_SPRG_VDSO_WRITE, val);
342	get_paca()->sprg_vdso = val;
343
344	put_cpu();
345
346	return 0;
347}
348/* We need to call this before SMP init */
349early_initcall(vdso_getcpu_init);
350#endif
351
352static struct page ** __init vdso_setup_pages(void *start, void *end)
353{
354	int i;
355	struct page **pagelist;
356	int pages = (end - start) >> PAGE_SHIFT;
357
358	pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
359	if (!pagelist)
360		panic("%s: Cannot allocate page list for VDSO", __func__);
361
362	for (i = 0; i < pages; i++)
363		pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
364
365	return pagelist;
366}
367
368static int __init vdso_init(void)
369{
370#ifdef CONFIG_PPC64
371	/*
372	 * Fill up the "systemcfg" stuff for backward compatibility
373	 */
374	strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
375	vdso_data->version.major = SYSTEMCFG_MAJOR;
376	vdso_data->version.minor = SYSTEMCFG_MINOR;
377	vdso_data->processor = mfspr(SPRN_PVR);
378	/*
379	 * Fake the old platform number for pSeries and add
380	 * in LPAR bit if necessary
381	 */
382	vdso_data->platform = 0x100;
383	if (firmware_has_feature(FW_FEATURE_LPAR))
384		vdso_data->platform |= 1;
385	vdso_data->physicalMemorySize = memblock_phys_mem_size();
386	vdso_data->dcache_size = ppc64_caches.l1d.size;
387	vdso_data->dcache_line_size = ppc64_caches.l1d.line_size;
388	vdso_data->icache_size = ppc64_caches.l1i.size;
389	vdso_data->icache_line_size = ppc64_caches.l1i.line_size;
390	vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
391	vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
392	vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
393	vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
 
 
 
 
 
 
394#endif /* CONFIG_PPC64 */
395
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
396	vdso_setup_syscall_map();
397
398	vdso_fixup_features();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
399
400	if (IS_ENABLED(CONFIG_VDSO32))
401		vdso32_spec.pages = vdso_setup_pages(&vdso32_start, &vdso32_end);
 
 
 
 
 
 
 
 
 
 
402
403	if (IS_ENABLED(CONFIG_PPC64))
404		vdso64_spec.pages = vdso_setup_pages(&vdso64_start, &vdso64_end);
405
406	smp_wmb();
 
407
408	return 0;
409}
410arch_initcall(vdso_init);