2 * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
3 * <benh@kernel.crashing.org>
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/smp.h>
17 #include <linux/smp_lock.h>
18 #include <linux/stddef.h>
19 #include <linux/unistd.h>
20 #include <linux/slab.h>
21 #include <linux/user.h>
22 #include <linux/elf.h>
23 #include <linux/security.h>
24 #include <linux/bootmem.h>
26 #include <asm/pgtable.h>
27 #include <asm/system.h>
28 #include <asm/processor.h>
30 #include <asm/mmu_context.h>
32 #include <asm/machdep.h>
33 #include <asm/cputable.h>
34 #include <asm/sections.h>
35 #include <asm/firmware.h>
37 #include <asm/vdso_datapage.h>
42 #define DBG(fmt...) printk(fmt)
47 /* Max supported size for symbol names */
48 #define MAX_SYMNAME 64
50 extern char vdso32_start, vdso32_end;
51 static void *vdso32_kbase = &vdso32_start;
52 unsigned int vdso32_pages;
53 unsigned long vdso32_sigtramp;
54 unsigned long vdso32_rt_sigtramp;
57 extern char vdso64_start, vdso64_end;
58 static void *vdso64_kbase = &vdso64_start;
59 unsigned int vdso64_pages;
60 unsigned long vdso64_rt_sigtramp;
61 #endif /* CONFIG_PPC64 */
64 * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
65 * Once the early boot kernel code no longer needs to muck around
66 * with it, it will become dynamically allocated
69 struct vdso_data data;
71 } vdso_data_store __attribute__((__section__(".data.page_aligned")));
72 struct vdso_data *vdso_data = &vdso_data_store.data;
74 /* Format of the patch table */
77 unsigned long ftr_mask, ftr_value;
82 /* Table of functions to patch based on the CPU type/revision
84 * Currently, we only change sync_dicache to do nothing on processors
85 * with a coherent icache
87 static struct vdso_patch_def vdso_patches[] = {
89 CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
90 "__kernel_sync_dicache", "__kernel_sync_dicache_p5"
94 "__kernel_gettimeofday", NULL
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 static void dump_one_vdso_page(struct page *pg, struct page *upg)
124 printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT),
127 if (upg/* && pg != upg*/) {
128 printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg)
136 static void dump_vdso_pages(struct vm_area_struct * vma)
140 if (!vma || test_thread_flag(TIF_32BIT)) {
141 printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase);
142 for (i=0; i<vdso32_pages; i++) {
143 struct page *pg = virt_to_page(vdso32_kbase +
145 struct page *upg = (vma && vma->vm_mm) ?
146 follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
148 dump_one_vdso_page(pg, upg);
151 if (!vma || !test_thread_flag(TIF_32BIT)) {
152 printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase);
153 for (i=0; i<vdso64_pages; i++) {
154 struct page *pg = virt_to_page(vdso64_kbase +
156 struct page *upg = (vma && vma->vm_mm) ?
157 follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
159 dump_one_vdso_page(pg, upg);
166 * Keep a dummy vma_close for now, it will prevent VMA merging.
168 static void vdso_vma_close(struct vm_area_struct * vma)
173 * Our nopage() function, maps in the actual vDSO kernel pages, they will
174 * be mapped read-only by do_no_page(), and eventually COW'ed, either
175 * right away for an initial write access, or by do_wp_page().
177 static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
178 unsigned long address, int *type)
180 unsigned long offset = address - vma->vm_start;
183 void *vbase = (vma->vm_mm->task_size > TASK_SIZE_USER32) ?
184 vdso64_kbase : vdso32_kbase;
186 void *vbase = vdso32_kbase;
189 DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",
190 current->comm, address, offset);
192 if (address < vma->vm_start || address > vma->vm_end)
193 return NOPAGE_SIGBUS;
196 * Last page is systemcfg.
198 if ((vma->vm_end - address) <= PAGE_SIZE)
199 pg = virt_to_page(vdso_data);
201 pg = virt_to_page(vbase + offset);
204 DBG(" ->page count: %d\n", page_count(pg));
209 static struct vm_operations_struct vdso_vmops = {
210 .close = vdso_vma_close,
211 .nopage = vdso_vma_nopage,
215 * This is called from binfmt_elf, we create the special vma for the
216 * vDSO and insert it into the mm struct tree
218 int arch_setup_additional_pages(struct linux_binprm *bprm,
219 int executable_stack)
221 struct mm_struct *mm = current->mm;
222 struct vm_area_struct *vma;
223 unsigned long vdso_pages;
224 unsigned long vdso_base;
228 if (test_thread_flag(TIF_32BIT)) {
229 vdso_pages = vdso32_pages;
230 vdso_base = VDSO32_MBASE;
232 vdso_pages = vdso64_pages;
233 vdso_base = VDSO64_MBASE;
236 vdso_pages = vdso32_pages;
237 vdso_base = VDSO32_MBASE;
240 current->mm->context.vdso_base = 0;
242 /* vDSO has a problem and was disabled, just don't "enable" it for the
247 /* Add a page to the vdso size for the data page */
251 * pick a base address for the vDSO in process space. We try to put it
252 * at vdso_base which is the "natural" base for it, but we might fail
253 * and end up putting it elsewhere.
255 down_write(&mm->mmap_sem);
256 vdso_base = get_unmapped_area(NULL, vdso_base,
257 vdso_pages << PAGE_SHIFT, 0, 0);
258 if (IS_ERR_VALUE(vdso_base)) {
264 /* Allocate a VMA structure and fill it up */
265 vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL);
271 vma->vm_start = vdso_base;
272 vma->vm_end = vma->vm_start + (vdso_pages << PAGE_SHIFT);
275 * our vma flags don't have VM_WRITE so by default, the process isn't
276 * allowed to write those pages.
277 * gdb can break that with ptrace interface, and thus trigger COW on
278 * those pages but it's then your responsibility to never do that on
279 * the "data" page of the vDSO or you'll stop getting kernel updates
280 * and your nice userland gettimeofday will be totally dead.
281 * It's fine to use that for setting breakpoints in the vDSO code
284 vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;
285 vma->vm_flags |= mm->def_flags;
286 vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
287 vma->vm_ops = &vdso_vmops;
290 rc = insert_vm_struct(mm, vma);
294 /* Put vDSO base into mm struct and account for memory usage */
295 current->mm->context.vdso_base = vdso_base;
296 mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
297 up_write(&mm->mmap_sem);
301 kmem_cache_free(vm_area_cachep, vma);
303 up_write(&mm->mmap_sem);
307 const char *arch_vma_name(struct vm_area_struct *vma)
309 if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
316 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
323 /* Grab section headers and strings so we can tell who is who */
324 sechdrs = (void *)ehdr + ehdr->e_shoff;
325 secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
327 /* Find the section they want */
328 for (i = 1; i < ehdr->e_shnum; i++) {
329 if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
331 *size = sechdrs[i].sh_size;
332 return (void *)ehdr + sechdrs[i].sh_offset;
339 static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
343 char name[MAX_SYMNAME], *c;
345 for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
346 if (lib->dynsym[i].st_name == 0)
348 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
350 c = strchr(name, '@');
353 if (strcmp(symname, name) == 0)
354 return &lib->dynsym[i];
359 /* Note that we assume the section is .text and the symbol is relative to
362 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
365 Elf32_Sym *sym = find_symbol32(lib, symname);
368 printk(KERN_WARNING "vDSO32: function %s not found !\n",
372 return sym->st_value - VDSO32_LBASE;
375 static int vdso_do_func_patch32(struct lib32_elfinfo *v32,
376 struct lib64_elfinfo *v64,
377 const char *orig, const char *fix)
379 Elf32_Sym *sym32_gen, *sym32_fix;
381 sym32_gen = find_symbol32(v32, orig);
382 if (sym32_gen == NULL) {
383 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
387 sym32_gen->st_name = 0;
390 sym32_fix = find_symbol32(v32, fix);
391 if (sym32_fix == NULL) {
392 printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
395 sym32_gen->st_value = sym32_fix->st_value;
396 sym32_gen->st_size = sym32_fix->st_size;
397 sym32_gen->st_info = sym32_fix->st_info;
398 sym32_gen->st_other = sym32_fix->st_other;
399 sym32_gen->st_shndx = sym32_fix->st_shndx;
407 static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
414 /* Grab section headers and strings so we can tell who is who */
415 sechdrs = (void *)ehdr + ehdr->e_shoff;
416 secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
418 /* Find the section they want */
419 for (i = 1; i < ehdr->e_shnum; i++) {
420 if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
422 *size = sechdrs[i].sh_size;
423 return (void *)ehdr + sechdrs[i].sh_offset;
431 static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
435 char name[MAX_SYMNAME], *c;
437 for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
438 if (lib->dynsym[i].st_name == 0)
440 strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
442 c = strchr(name, '@');
445 if (strcmp(symname, name) == 0)
446 return &lib->dynsym[i];
451 /* Note that we assume the section is .text and the symbol is relative to
454 static unsigned long __init find_function64(struct lib64_elfinfo *lib,
457 Elf64_Sym *sym = find_symbol64(lib, symname);
460 printk(KERN_WARNING "vDSO64: function %s not found !\n",
464 #ifdef VDS64_HAS_DESCRIPTORS
465 return *((u64 *)(vdso64_kbase + sym->st_value - VDSO64_LBASE)) -
468 return sym->st_value - VDSO64_LBASE;
472 static int vdso_do_func_patch64(struct lib32_elfinfo *v32,
473 struct lib64_elfinfo *v64,
474 const char *orig, const char *fix)
476 Elf64_Sym *sym64_gen, *sym64_fix;
478 sym64_gen = find_symbol64(v64, orig);
479 if (sym64_gen == NULL) {
480 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
484 sym64_gen->st_name = 0;
487 sym64_fix = find_symbol64(v64, fix);
488 if (sym64_fix == NULL) {
489 printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
492 sym64_gen->st_value = sym64_fix->st_value;
493 sym64_gen->st_size = sym64_fix->st_size;
494 sym64_gen->st_info = sym64_fix->st_info;
495 sym64_gen->st_other = sym64_fix->st_other;
496 sym64_gen->st_shndx = sym64_fix->st_shndx;
501 #endif /* CONFIG_PPC64 */
504 static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
505 struct lib64_elfinfo *v64)
510 * Locate symbol tables & text section
513 v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
514 v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
515 if (v32->dynsym == NULL || v32->dynstr == NULL) {
516 printk(KERN_ERR "vDSO32: required symbol section not found\n");
519 sect = find_section32(v32->hdr, ".text", NULL);
521 printk(KERN_ERR "vDSO32: the .text section was not found\n");
524 v32->text = sect - vdso32_kbase;
527 v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
528 v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
529 if (v64->dynsym == NULL || v64->dynstr == NULL) {
530 printk(KERN_ERR "vDSO64: required symbol section not found\n");
533 sect = find_section64(v64->hdr, ".text", NULL);
535 printk(KERN_ERR "vDSO64: the .text section was not found\n");
538 v64->text = sect - vdso64_kbase;
539 #endif /* CONFIG_PPC64 */
544 static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
545 struct lib64_elfinfo *v64)
548 * Find signal trampolines
552 vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
554 vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32");
555 vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
558 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
559 struct lib64_elfinfo *v64)
565 sym64 = find_symbol64(v64, "__kernel_datapage_offset");
567 printk(KERN_ERR "vDSO64: Can't find symbol "
568 "__kernel_datapage_offset !\n");
571 *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
572 (vdso64_pages << PAGE_SHIFT) -
573 (sym64->st_value - VDSO64_LBASE);
574 #endif /* CONFIG_PPC64 */
576 sym32 = find_symbol32(v32, "__kernel_datapage_offset");
578 printk(KERN_ERR "vDSO32: Can't find symbol "
579 "__kernel_datapage_offset !\n");
582 *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
583 (vdso32_pages << PAGE_SHIFT) -
584 (sym32->st_value - VDSO32_LBASE);
589 static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
590 struct lib64_elfinfo *v64)
594 for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
595 struct vdso_patch_def *patch = &vdso_patches[i];
596 int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
601 DBG("replacing %s with %s...\n", patch->gen_name,
602 patch->fix_name ? "NONE" : patch->fix_name);
605 * Patch the 32 bits and 64 bits symbols. Note that we do not
606 * patch the "." symbol on 64 bits.
607 * It would be easy to do, but doesn't seem to be necessary,
608 * patching the OPD symbol is enough.
610 vdso_do_func_patch32(v32, v64, patch->gen_name,
613 vdso_do_func_patch64(v32, v64, patch->gen_name,
615 #endif /* CONFIG_PPC64 */
622 static __init int vdso_setup(void)
624 struct lib32_elfinfo v32;
625 struct lib64_elfinfo v64;
627 v32.hdr = vdso32_kbase;
629 v64.hdr = vdso64_kbase;
631 if (vdso_do_find_sections(&v32, &v64))
634 if (vdso_fixup_datapage(&v32, &v64))
637 if (vdso_fixup_alt_funcs(&v32, &v64))
640 vdso_setup_trampolines(&v32, &v64);
646 * Called from setup_arch to initialize the bitmap of available
647 * syscalls in the systemcfg page
649 static void __init vdso_setup_syscall_map(void)
652 extern unsigned long *sys_call_table;
653 extern unsigned long sys_ni_syscall;
656 for (i = 0; i < __NR_syscalls; i++) {
658 if (sys_call_table[i*2] != sys_ni_syscall)
659 vdso_data->syscall_map_64[i >> 5] |=
660 0x80000000UL >> (i & 0x1f);
661 if (sys_call_table[i*2+1] != sys_ni_syscall)
662 vdso_data->syscall_map_32[i >> 5] |=
663 0x80000000UL >> (i & 0x1f);
664 #else /* CONFIG_PPC64 */
665 if (sys_call_table[i] != sys_ni_syscall)
666 vdso_data->syscall_map_32[i >> 5] |=
667 0x80000000UL >> (i & 0x1f);
668 #endif /* CONFIG_PPC64 */
673 void __init vdso_init(void)
679 * Fill up the "systemcfg" stuff for backward compatiblity
681 strcpy(vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
682 vdso_data->version.major = SYSTEMCFG_MAJOR;
683 vdso_data->version.minor = SYSTEMCFG_MINOR;
684 vdso_data->processor = mfspr(SPRN_PVR);
686 * Fake the old platform number for pSeries and iSeries and add
687 * in LPAR bit if necessary
689 vdso_data->platform = machine_is(iseries) ? 0x200 : 0x100;
690 if (firmware_has_feature(FW_FEATURE_LPAR))
691 vdso_data->platform |= 1;
692 vdso_data->physicalMemorySize = lmb_phys_mem_size();
693 vdso_data->dcache_size = ppc64_caches.dsize;
694 vdso_data->dcache_line_size = ppc64_caches.dline_size;
695 vdso_data->icache_size = ppc64_caches.isize;
696 vdso_data->icache_line_size = ppc64_caches.iline_size;
699 * Calculate the size of the 64 bits vDSO
701 vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
702 DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
703 #endif /* CONFIG_PPC64 */
707 * Calculate the size of the 32 bits vDSO
709 vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
710 DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
714 * Setup the syscall map in the vDOS
716 vdso_setup_syscall_map();
718 * Initialize the vDSO images in memory, that is do necessary
719 * fixups of vDSO symbols, locate trampolines, etc...
722 printk(KERN_ERR "vDSO setup failure, not enabled !\n");
730 /* Make sure pages are in the correct state */
731 for (i = 0; i < vdso32_pages; i++) {
732 struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
733 ClearPageReserved(pg);
738 for (i = 0; i < vdso64_pages; i++) {
739 struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
740 ClearPageReserved(pg);
743 #endif /* CONFIG_PPC64 */
745 get_page(virt_to_page(vdso_data));
748 int in_gate_area_no_task(unsigned long addr)
753 int in_gate_area(struct task_struct *task, unsigned long addr)
758 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)