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/pgtable.h>
22 #include <asm/processor.h>
24 #include <asm/mmu_context.h>
26 #include <asm/machdep.h>
27 #include <asm/cputable.h>
28 #include <asm/sections.h>
29 #include <asm/firmware.h>
31 #include <asm/vdso_datapage.h>
32 #include <asm/setup.h>
37 #define DBG(fmt...) printk(fmt)
42 /* Max supported size for symbol names */
43 #define MAX_SYMNAME 64
45 /* The alignment of the vDSO */
46 #define VDSO_ALIGNMENT (1 << 16)
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;
55 extern char vdso32_start, vdso32_end;
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 */
66 static int vdso_ready;
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
74 struct vdso_data data;
76 } vdso_data_store __page_aligned_data;
77 struct vdso_data *vdso_data = &vdso_data_store.data;
79 /* Format of the patch table */
82 unsigned long ftr_mask, ftr_value;
87 /* Table of functions to patch based on the CPU type/revision
89 * Currently, we only change sync_dicache to do nothing on processors
90 * with a coherent icache
92 static struct vdso_patch_def vdso_patches[] = {
94 CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
95 "__kernel_sync_dicache", "__kernel_sync_dicache_p5"
100 * Some infos carried around for each of them during parsing at
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 */
116 unsigned long dynsymsize;
123 * This is called from binfmt_elf, we create the special vma for the
124 * vDSO and insert it into the mm struct tree
126 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
128 struct mm_struct *mm = current->mm;
129 struct page **vdso_pagelist;
130 unsigned long vdso_pages;
131 unsigned long vdso_base;
138 if (is_32bit_task()) {
139 vdso_pagelist = vdso32_pagelist;
140 vdso_pages = vdso32_pages;
141 vdso_base = VDSO32_MBASE;
143 vdso_pagelist = vdso64_pagelist;
144 vdso_pages = vdso64_pages;
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.
153 vdso_pagelist = vdso32_pagelist;
154 vdso_pages = vdso32_pages;
155 vdso_base = VDSO32_MBASE;
158 current->mm->context.vdso_base = 0;
160 /* vDSO has a problem and was disabled, just don't "enable" it for the
165 /* Add a page to the vdso size for the data page */
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.
174 if (down_write_killable(&mm->mmap_sem))
176 vdso_base = get_unmapped_area(NULL, vdso_base,
177 (vdso_pages << PAGE_SHIFT) +
178 ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
180 if (IS_ERR_VALUE(vdso_base)) {
185 /* Add required alignment. */
186 vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
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).
193 current->mm->context.vdso_base = vdso_base;
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
205 rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
207 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
210 current->mm->context.vdso_base = 0;
214 up_write(&mm->mmap_sem);
218 up_write(&mm->mmap_sem);
222 const char *arch_vma_name(struct vm_area_struct *vma)
224 if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
232 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
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;
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) {
247 *size = sechdrs[i].sh_size;
248 return (void *)ehdr + sechdrs[i].sh_offset;
255 static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
259 char name[MAX_SYMNAME], *c;
261 for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
262 if (lib->dynsym[i].st_name == 0)
264 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
266 c = strchr(name, '@');
269 if (strcmp(symname, name) == 0)
270 return &lib->dynsym[i];
275 /* Note that we assume the section is .text and the symbol is relative to
278 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
281 Elf32_Sym *sym = find_symbol32(lib, symname);
284 printk(KERN_WARNING "vDSO32: function %s not found !\n",
288 return sym->st_value - VDSO32_LBASE;
291 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
292 struct lib64_elfinfo *v64,
293 const char *orig, const char *fix)
295 Elf32_Sym *sym32_gen, *sym32_fix;
297 sym32_gen = find_symbol32(v32, orig);
298 if (sym32_gen == NULL) {
299 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
303 sym32_gen->st_name = 0;
306 sym32_fix = find_symbol32(v32, fix);
307 if (sym32_fix == NULL) {
308 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
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;
319 #else /* !CONFIG_VDSO32 */
320 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
326 static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
327 struct lib64_elfinfo *v64,
328 const char *orig, const char *fix)
332 #endif /* CONFIG_VDSO32 */
337 static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
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;
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) {
352 *size = sechdrs[i].sh_size;
353 return (void *)ehdr + sechdrs[i].sh_offset;
361 static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
365 char name[MAX_SYMNAME], *c;
367 for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
368 if (lib->dynsym[i].st_name == 0)
370 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
372 c = strchr(name, '@');
375 if (strcmp(symname, name) == 0)
376 return &lib->dynsym[i];
381 /* Note that we assume the section is .text and the symbol is relative to
384 static unsigned long __init find_function64(struct lib64_elfinfo *lib,
387 Elf64_Sym *sym = find_symbol64(lib, symname);
390 printk(KERN_WARNING "vDSO64: function %s not found !\n",
394 #ifdef VDS64_HAS_DESCRIPTORS
395 return *((u64 *)(vdso64_kbase + sym->st_value - VDSO64_LBASE)) -
398 return sym->st_value - VDSO64_LBASE;
402 static int __init vdso_do_func_patch64(struct lib32_elfinfo *v32,
403 struct lib64_elfinfo *v64,
404 const char *orig, const char *fix)
406 Elf64_Sym *sym64_gen, *sym64_fix;
408 sym64_gen = find_symbol64(v64, orig);
409 if (sym64_gen == NULL) {
410 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
414 sym64_gen->st_name = 0;
417 sym64_fix = find_symbol64(v64, fix);
418 if (sym64_fix == NULL) {
419 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
422 sym64_gen->st_value = sym64_fix->st_value;
423 sym64_gen->st_size = sym64_fix->st_size;
424 sym64_gen->st_info = sym64_fix->st_info;
425 sym64_gen->st_other = sym64_fix->st_other;
426 sym64_gen->st_shndx = sym64_fix->st_shndx;
431 #endif /* CONFIG_PPC64 */
434 static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
435 struct lib64_elfinfo *v64)
440 * Locate symbol tables & text section
444 v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
445 v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
446 if (v32->dynsym == NULL || v32->dynstr == NULL) {
447 printk(KERN_ERR "vDSO32: required symbol section not found\n");
450 sect = find_section32(v32->hdr, ".text", NULL);
452 printk(KERN_ERR "vDSO32: the .text section was not found\n");
455 v32->text = sect - vdso32_kbase;
459 v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
460 v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
461 if (v64->dynsym == NULL || v64->dynstr == NULL) {
462 printk(KERN_ERR "vDSO64: required symbol section not found\n");
465 sect = find_section64(v64->hdr, ".text", NULL);
467 printk(KERN_ERR "vDSO64: the .text section was not found\n");
470 v64->text = sect - vdso64_kbase;
471 #endif /* CONFIG_PPC64 */
476 static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
477 struct lib64_elfinfo *v64)
480 * Find signal trampolines
484 vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
486 vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32");
487 vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
490 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
491 struct lib64_elfinfo *v64)
499 sym64 = find_symbol64(v64, "__kernel_datapage_offset");
501 printk(KERN_ERR "vDSO64: Can't find symbol "
502 "__kernel_datapage_offset !\n");
505 *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
506 (vdso64_pages << PAGE_SHIFT) -
507 (sym64->st_value - VDSO64_LBASE);
508 #endif /* CONFIG_PPC64 */
511 sym32 = find_symbol32(v32, "__kernel_datapage_offset");
513 printk(KERN_ERR "vDSO32: Can't find symbol "
514 "__kernel_datapage_offset !\n");
517 *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
518 (vdso32_pages << PAGE_SHIFT) -
519 (sym32->st_value - VDSO32_LBASE);
526 static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
527 struct lib64_elfinfo *v64)
533 start = find_section64(v64->hdr, "__ftr_fixup", &size);
535 do_feature_fixups(cur_cpu_spec->cpu_features,
536 start, start + size);
538 start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size);
540 do_feature_fixups(cur_cpu_spec->mmu_features,
541 start, start + size);
543 start = find_section64(v64->hdr, "__fw_ftr_fixup", &size);
545 do_feature_fixups(powerpc_firmware_features,
546 start, start + size);
548 start = find_section64(v64->hdr, "__lwsync_fixup", &size);
550 do_lwsync_fixups(cur_cpu_spec->cpu_features,
551 start, start + size);
552 #endif /* CONFIG_PPC64 */
555 start = find_section32(v32->hdr, "__ftr_fixup", &size);
557 do_feature_fixups(cur_cpu_spec->cpu_features,
558 start, start + size);
560 start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size);
562 do_feature_fixups(cur_cpu_spec->mmu_features,
563 start, start + size);
566 start = find_section32(v32->hdr, "__fw_ftr_fixup", &size);
568 do_feature_fixups(powerpc_firmware_features,
569 start, start + size);
570 #endif /* CONFIG_PPC64 */
572 start = find_section32(v32->hdr, "__lwsync_fixup", &size);
574 do_lwsync_fixups(cur_cpu_spec->cpu_features,
575 start, start + size);
581 static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
582 struct lib64_elfinfo *v64)
586 for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
587 struct vdso_patch_def *patch = &vdso_patches[i];
588 int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
593 DBG("replacing %s with %s...\n", patch->gen_name,
594 patch->fix_name ? "NONE" : patch->fix_name);
597 * Patch the 32 bits and 64 bits symbols. Note that we do not
598 * patch the "." symbol on 64 bits.
599 * It would be easy to do, but doesn't seem to be necessary,
600 * patching the OPD symbol is enough.
602 vdso_do_func_patch32(v32, v64, patch->gen_name,
605 vdso_do_func_patch64(v32, v64, patch->gen_name,
607 #endif /* CONFIG_PPC64 */
614 static __init int vdso_setup(void)
616 struct lib32_elfinfo v32;
617 struct lib64_elfinfo v64;
619 v32.hdr = vdso32_kbase;
621 v64.hdr = vdso64_kbase;
623 if (vdso_do_find_sections(&v32, &v64))
626 if (vdso_fixup_datapage(&v32, &v64))
629 if (vdso_fixup_features(&v32, &v64))
632 if (vdso_fixup_alt_funcs(&v32, &v64))
635 vdso_setup_trampolines(&v32, &v64);
641 * Called from setup_arch to initialize the bitmap of available
642 * syscalls in the systemcfg page
644 static void __init vdso_setup_syscall_map(void)
647 extern unsigned long *sys_call_table;
649 extern unsigned long *compat_sys_call_table;
651 extern unsigned long sys_ni_syscall;
654 for (i = 0; i < NR_syscalls; i++) {
656 if (sys_call_table[i] != sys_ni_syscall)
657 vdso_data->syscall_map_64[i >> 5] |=
658 0x80000000UL >> (i & 0x1f);
659 if (compat_sys_call_table[i] != sys_ni_syscall)
660 vdso_data->syscall_map_32[i >> 5] |=
661 0x80000000UL >> (i & 0x1f);
662 #else /* CONFIG_PPC64 */
663 if (sys_call_table[i] != sys_ni_syscall)
664 vdso_data->syscall_map_32[i >> 5] |=
665 0x80000000UL >> (i & 0x1f);
666 #endif /* CONFIG_PPC64 */
671 int vdso_getcpu_init(void)
673 unsigned long cpu, node, val;
676 * SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node
677 * in the next 16 bits. The VDSO uses this to implement getcpu().
680 WARN_ON_ONCE(cpu > 0xffff);
682 node = cpu_to_node(cpu);
683 WARN_ON_ONCE(node > 0xffff);
685 val = (cpu & 0xffff) | ((node & 0xffff) << 16);
686 mtspr(SPRN_SPRG_VDSO_WRITE, val);
687 get_paca()->sprg_vdso = val;
693 /* We need to call this before SMP init */
694 early_initcall(vdso_getcpu_init);
697 static int __init vdso_init(void)
703 * Fill up the "systemcfg" stuff for backward compatibility
705 strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
706 vdso_data->version.major = SYSTEMCFG_MAJOR;
707 vdso_data->version.minor = SYSTEMCFG_MINOR;
708 vdso_data->processor = mfspr(SPRN_PVR);
710 * Fake the old platform number for pSeries and add
711 * in LPAR bit if necessary
713 vdso_data->platform = 0x100;
714 if (firmware_has_feature(FW_FEATURE_LPAR))
715 vdso_data->platform |= 1;
716 vdso_data->physicalMemorySize = memblock_phys_mem_size();
717 vdso_data->dcache_size = ppc64_caches.l1d.size;
718 vdso_data->dcache_line_size = ppc64_caches.l1d.line_size;
719 vdso_data->icache_size = ppc64_caches.l1i.size;
720 vdso_data->icache_line_size = ppc64_caches.l1i.line_size;
721 vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
722 vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
723 vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
724 vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
727 * Calculate the size of the 64 bits vDSO
729 vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
730 DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
732 vdso_data->dcache_block_size = L1_CACHE_BYTES;
733 vdso_data->dcache_log_block_size = L1_CACHE_SHIFT;
734 vdso_data->icache_block_size = L1_CACHE_BYTES;
735 vdso_data->icache_log_block_size = L1_CACHE_SHIFT;
736 #endif /* CONFIG_PPC64 */
740 vdso32_kbase = &vdso32_start;
743 * Calculate the size of the 32 bits vDSO
745 vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
746 DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
751 * Setup the syscall map in the vDOS
753 vdso_setup_syscall_map();
756 * Initialize the vDSO images in memory, that is do necessary
757 * fixups of vDSO symbols, locate trampolines, etc...
760 printk(KERN_ERR "vDSO setup failure, not enabled !\n");
769 /* Make sure pages are in the correct state */
770 vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *),
772 BUG_ON(vdso32_pagelist == NULL);
773 for (i = 0; i < vdso32_pages; i++) {
774 struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
776 vdso32_pagelist[i] = pg;
778 vdso32_pagelist[i++] = virt_to_page(vdso_data);
779 vdso32_pagelist[i] = NULL;
783 vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *),
785 BUG_ON(vdso64_pagelist == NULL);
786 for (i = 0; i < vdso64_pages; i++) {
787 struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
789 vdso64_pagelist[i] = pg;
791 vdso64_pagelist[i++] = virt_to_page(vdso_data);
792 vdso64_pagelist[i] = NULL;
793 #endif /* CONFIG_PPC64 */
795 get_page(virt_to_page(vdso_data));
802 arch_initcall(vdso_init);