1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
5 * <benh@kernel.crashing.org>
8 #include <linux/errno.h>
9 #include <linux/sched.h>
10 #include <linux/kernel.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>
21 #include <asm/processor.h>
23 #include <asm/mmu_context.h>
25 #include <asm/machdep.h>
26 #include <asm/cputable.h>
27 #include <asm/sections.h>
28 #include <asm/firmware.h>
30 #include <asm/vdso_datapage.h>
31 #include <asm/setup.h>
36 #define DBG(fmt...) printk(fmt)
41 /* Max supported size for symbol names */
42 #define MAX_SYMNAME 64
44 /* The alignment of the vDSO */
45 #define VDSO_ALIGNMENT (1 << 16)
47 static unsigned int vdso32_pages;
48 static void *vdso32_kbase;
49 static struct page **vdso32_pagelist;
50 unsigned long vdso32_sigtramp;
51 unsigned long vdso32_rt_sigtramp;
54 extern char vdso32_start, vdso32_end;
58 extern char vdso64_start, vdso64_end;
59 static void *vdso64_kbase = &vdso64_start;
60 static unsigned int vdso64_pages;
61 static struct page **vdso64_pagelist;
62 unsigned long vdso64_rt_sigtramp;
63 #endif /* CONFIG_PPC64 */
65 static int vdso_ready;
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
73 struct vdso_data data;
75 } vdso_data_store __page_aligned_data;
76 struct vdso_data *vdso_data = &vdso_data_store.data;
78 /* Format of the patch table */
81 unsigned long ftr_mask, ftr_value;
86 /* Table of functions to patch based on the CPU type/revision
88 * Currently, we only change sync_dicache to do nothing on processors
89 * with a coherent icache
91 static struct vdso_patch_def vdso_patches[] = {
93 CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
94 "__kernel_sync_dicache", "__kernel_sync_dicache_p5"
99 * Some infos carried around for each of them during parsing at
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 */
115 unsigned long dynsymsize;
122 * This is called from binfmt_elf, we create the special vma for the
123 * vDSO and insert it into the mm struct tree
125 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
127 struct mm_struct *mm = current->mm;
128 struct page **vdso_pagelist;
129 unsigned long vdso_pages;
130 unsigned long vdso_base;
137 if (is_32bit_task()) {
138 vdso_pagelist = vdso32_pagelist;
139 vdso_pages = vdso32_pages;
140 vdso_base = VDSO32_MBASE;
142 vdso_pagelist = vdso64_pagelist;
143 vdso_pages = vdso64_pages;
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.
152 vdso_pagelist = vdso32_pagelist;
153 vdso_pages = vdso32_pages;
154 vdso_base = VDSO32_MBASE;
157 current->mm->context.vdso_base = 0;
159 /* vDSO has a problem and was disabled, just don't "enable" it for the
164 /* Add a page to the vdso size for the data page */
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.
173 if (mmap_write_lock_killable(mm))
175 vdso_base = get_unmapped_area(NULL, vdso_base,
176 (vdso_pages << PAGE_SHIFT) +
177 ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
179 if (IS_ERR_VALUE(vdso_base)) {
184 /* Add required alignment. */
185 vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
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).
192 current->mm->context.vdso_base = vdso_base;
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
204 rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
206 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
209 current->mm->context.vdso_base = 0;
213 mmap_write_unlock(mm);
217 mmap_write_unlock(mm);
221 const char *arch_vma_name(struct vm_area_struct *vma)
223 if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
231 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
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;
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) {
246 *size = sechdrs[i].sh_size;
247 return (void *)ehdr + sechdrs[i].sh_offset;
254 static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
258 char name[MAX_SYMNAME], *c;
260 for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
261 if (lib->dynsym[i].st_name == 0)
263 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
265 c = strchr(name, '@');
268 if (strcmp(symname, name) == 0)
269 return &lib->dynsym[i];
274 /* Note that we assume the section is .text and the symbol is relative to
277 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
280 Elf32_Sym *sym = find_symbol32(lib, symname);
283 printk(KERN_WARNING "vDSO32: function %s not found !\n",
287 return sym->st_value - VDSO32_LBASE;
290 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
291 struct lib64_elfinfo *v64,
292 const char *orig, const char *fix)
294 Elf32_Sym *sym32_gen, *sym32_fix;
296 sym32_gen = find_symbol32(v32, orig);
297 if (sym32_gen == NULL) {
298 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
302 sym32_gen->st_name = 0;
305 sym32_fix = find_symbol32(v32, fix);
306 if (sym32_fix == NULL) {
307 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
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;
318 #else /* !CONFIG_VDSO32 */
319 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
325 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
326 struct lib64_elfinfo *v64,
327 const char *orig, const char *fix)
331 #endif /* CONFIG_VDSO32 */
336 static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
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;
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) {
351 *size = sechdrs[i].sh_size;
352 return (void *)ehdr + sechdrs[i].sh_offset;
360 static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
364 char name[MAX_SYMNAME], *c;
366 for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
367 if (lib->dynsym[i].st_name == 0)
369 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
371 c = strchr(name, '@');
374 if (strcmp(symname, name) == 0)
375 return &lib->dynsym[i];
380 /* Note that we assume the section is .text and the symbol is relative to
383 static unsigned long __init find_function64(struct lib64_elfinfo *lib,
386 Elf64_Sym *sym = find_symbol64(lib, symname);
389 printk(KERN_WARNING "vDSO64: function %s not found !\n",
393 return sym->st_value - VDSO64_LBASE;
396 static int __init vdso_do_func_patch64(struct lib32_elfinfo *v32,
397 struct lib64_elfinfo *v64,
398 const char *orig, const char *fix)
400 Elf64_Sym *sym64_gen, *sym64_fix;
402 sym64_gen = find_symbol64(v64, orig);
403 if (sym64_gen == NULL) {
404 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
408 sym64_gen->st_name = 0;
411 sym64_fix = find_symbol64(v64, fix);
412 if (sym64_fix == NULL) {
413 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
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;
425 #endif /* CONFIG_PPC64 */
428 static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
429 struct lib64_elfinfo *v64)
434 * Locate symbol tables & text section
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");
444 sect = find_section32(v32->hdr, ".text", NULL);
446 printk(KERN_ERR "vDSO32: the .text section was not found\n");
449 v32->text = sect - vdso32_kbase;
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");
459 sect = find_section64(v64->hdr, ".text", NULL);
461 printk(KERN_ERR "vDSO64: the .text section was not found\n");
464 v64->text = sect - vdso64_kbase;
465 #endif /* CONFIG_PPC64 */
470 static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
471 struct lib64_elfinfo *v64)
474 * Find signal trampolines
478 vdso64_rt_sigtramp = find_function64(v64, "__kernel_start_sigtramp_rt64");
480 vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32");
481 vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
484 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
485 struct lib64_elfinfo *v64)
493 sym64 = find_symbol64(v64, "__kernel_datapage_offset");
495 printk(KERN_ERR "vDSO64: Can't find symbol "
496 "__kernel_datapage_offset !\n");
499 *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
500 (vdso64_pages << PAGE_SHIFT) -
501 (sym64->st_value - VDSO64_LBASE);
502 #endif /* CONFIG_PPC64 */
505 sym32 = find_symbol32(v32, "__kernel_datapage_offset");
507 printk(KERN_ERR "vDSO32: Can't find symbol "
508 "__kernel_datapage_offset !\n");
511 *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
512 (vdso32_pages << PAGE_SHIFT) -
513 (sym32->st_value - VDSO32_LBASE);
520 static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
521 struct lib64_elfinfo *v64)
527 start = find_section64(v64->hdr, "__ftr_fixup", &size);
529 do_feature_fixups(cur_cpu_spec->cpu_features,
530 start, start + size);
532 start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size);
534 do_feature_fixups(cur_cpu_spec->mmu_features,
535 start, start + size);
537 start = find_section64(v64->hdr, "__fw_ftr_fixup", &size);
539 do_feature_fixups(powerpc_firmware_features,
540 start, start + size);
542 start = find_section64(v64->hdr, "__lwsync_fixup", &size);
544 do_lwsync_fixups(cur_cpu_spec->cpu_features,
545 start, start + size);
546 #endif /* CONFIG_PPC64 */
549 start = find_section32(v32->hdr, "__ftr_fixup", &size);
551 do_feature_fixups(cur_cpu_spec->cpu_features,
552 start, start + size);
554 start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size);
556 do_feature_fixups(cur_cpu_spec->mmu_features,
557 start, start + size);
560 start = find_section32(v32->hdr, "__fw_ftr_fixup", &size);
562 do_feature_fixups(powerpc_firmware_features,
563 start, start + size);
564 #endif /* CONFIG_PPC64 */
566 start = find_section32(v32->hdr, "__lwsync_fixup", &size);
568 do_lwsync_fixups(cur_cpu_spec->cpu_features,
569 start, start + size);
575 static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
576 struct lib64_elfinfo *v64)
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)
587 DBG("replacing %s with %s...\n", patch->gen_name,
588 patch->fix_name ? "NONE" : patch->fix_name);
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.
596 vdso_do_func_patch32(v32, v64, patch->gen_name,
599 vdso_do_func_patch64(v32, v64, patch->gen_name,
601 #endif /* CONFIG_PPC64 */
608 static __init int vdso_setup(void)
610 struct lib32_elfinfo v32;
611 struct lib64_elfinfo v64;
613 v32.hdr = vdso32_kbase;
615 v64.hdr = vdso64_kbase;
617 if (vdso_do_find_sections(&v32, &v64))
620 if (vdso_fixup_datapage(&v32, &v64))
623 if (vdso_fixup_features(&v32, &v64))
626 if (vdso_fixup_alt_funcs(&v32, &v64))
629 vdso_setup_trampolines(&v32, &v64);
635 * Called from setup_arch to initialize the bitmap of available
636 * syscalls in the systemcfg page
638 static void __init vdso_setup_syscall_map(void)
641 extern unsigned long *sys_call_table;
643 extern unsigned long *compat_sys_call_table;
645 extern unsigned long sys_ni_syscall;
648 for (i = 0; i < NR_syscalls; i++) {
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 */
666 int vdso_getcpu_init(void)
668 unsigned long cpu, node, val;
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().
675 WARN_ON_ONCE(cpu > 0xffff);
677 node = cpu_to_node(cpu);
678 WARN_ON_ONCE(node > 0xffff);
680 val = (cpu & 0xffff) | ((node & 0xffff) << 16);
681 mtspr(SPRN_SPRG_VDSO_WRITE, val);
682 get_paca()->sprg_vdso = val;
688 /* We need to call this before SMP init */
689 early_initcall(vdso_getcpu_init);
692 static int __init vdso_init(void)
698 * Fill up the "systemcfg" stuff for backward compatibility
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);
705 * Fake the old platform number for pSeries and add
706 * in LPAR bit if necessary
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;
722 * Calculate the size of the 64 bits vDSO
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 */
730 vdso32_kbase = &vdso32_start;
733 * Calculate the size of the 32 bits vDSO
735 vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
736 DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
741 * Setup the syscall map in the vDOS
743 vdso_setup_syscall_map();
746 * Initialize the vDSO images in memory, that is do necessary
747 * fixups of vDSO symbols, locate trampolines, etc...
750 printk(KERN_ERR "vDSO setup failure, not enabled !\n");
759 /* Make sure pages are in the correct state */
760 vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *),
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);
766 vdso32_pagelist[i] = pg;
768 vdso32_pagelist[i++] = virt_to_page(vdso_data);
769 vdso32_pagelist[i] = NULL;
773 vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *),
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);
779 vdso64_pagelist[i] = pg;
781 vdso64_pagelist[i++] = virt_to_page(vdso_data);
782 vdso64_pagelist[i] = NULL;
783 #endif /* CONFIG_PPC64 */
785 get_page(virt_to_page(vdso_data));
792 arch_initcall(vdso_init);