| /* |
| * linux/arch/ppc64/kernel/vdso.c |
| * |
| * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp. |
| * <benh@kernel.crashing.org> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/module.h> |
| #include <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/smp_lock.h> |
| #include <linux/stddef.h> |
| #include <linux/unistd.h> |
| #include <linux/slab.h> |
| #include <linux/user.h> |
| #include <linux/elf.h> |
| #include <linux/security.h> |
| #include <linux/bootmem.h> |
| |
| #include <asm/pgtable.h> |
| #include <asm/system.h> |
| #include <asm/processor.h> |
| #include <asm/mmu.h> |
| #include <asm/mmu_context.h> |
| #include <asm/machdep.h> |
| #include <asm/cputable.h> |
| #include <asm/sections.h> |
| #include <asm/systemcfg.h> |
| #include <asm/vdso.h> |
| |
| #undef DEBUG |
| |
| #ifdef DEBUG |
| #define DBG(fmt...) printk(fmt) |
| #else |
| #define DBG(fmt...) |
| #endif |
| |
| |
| /* |
| * The vDSOs themselves are here |
| */ |
| extern char vdso64_start, vdso64_end; |
| extern char vdso32_start, vdso32_end; |
| |
| static void *vdso64_kbase = &vdso64_start; |
| static void *vdso32_kbase = &vdso32_start; |
| |
| unsigned int vdso64_pages; |
| unsigned int vdso32_pages; |
| |
| /* Signal trampolines user addresses */ |
| |
| unsigned long vdso64_rt_sigtramp; |
| unsigned long vdso32_sigtramp; |
| unsigned long vdso32_rt_sigtramp; |
| |
| /* Format of the patch table */ |
| struct vdso_patch_def |
| { |
| u32 pvr_mask, pvr_value; |
| const char *gen_name; |
| const char *fix_name; |
| }; |
| |
| /* Table of functions to patch based on the CPU type/revision |
| * |
| * TODO: Improve by adding whole lists for each entry |
| */ |
| static struct vdso_patch_def vdso_patches[] = { |
| { |
| 0xffff0000, 0x003a0000, /* POWER5 */ |
| "__kernel_sync_dicache", "__kernel_sync_dicache_p5" |
| }, |
| { |
| 0xffff0000, 0x003b0000, /* POWER5 */ |
| "__kernel_sync_dicache", "__kernel_sync_dicache_p5" |
| }, |
| }; |
| |
| /* |
| * Some infos carried around for each of them during parsing at |
| * boot time. |
| */ |
| struct lib32_elfinfo |
| { |
| Elf32_Ehdr *hdr; /* ptr to ELF */ |
| Elf32_Sym *dynsym; /* ptr to .dynsym section */ |
| unsigned long dynsymsize; /* size of .dynsym section */ |
| char *dynstr; /* ptr to .dynstr section */ |
| unsigned long text; /* offset of .text section in .so */ |
| }; |
| |
| struct lib64_elfinfo |
| { |
| Elf64_Ehdr *hdr; |
| Elf64_Sym *dynsym; |
| unsigned long dynsymsize; |
| char *dynstr; |
| unsigned long text; |
| }; |
| |
| |
| #ifdef __DEBUG |
| static void dump_one_vdso_page(struct page *pg, struct page *upg) |
| { |
| printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT), |
| page_count(pg), |
| pg->flags); |
| if (upg/* && pg != upg*/) { |
| printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg) << PAGE_SHIFT), |
| page_count(upg), |
| upg->flags); |
| } |
| printk("\n"); |
| } |
| |
| static void dump_vdso_pages(struct vm_area_struct * vma) |
| { |
| int i; |
| |
| if (!vma || test_thread_flag(TIF_32BIT)) { |
| printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase); |
| for (i=0; i<vdso32_pages; i++) { |
| struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); |
| struct page *upg = (vma && vma->vm_mm) ? |
| follow_page(vma->vm_mm, vma->vm_start + i*PAGE_SIZE, 0) |
| : NULL; |
| dump_one_vdso_page(pg, upg); |
| } |
| } |
| if (!vma || !test_thread_flag(TIF_32BIT)) { |
| printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase); |
| for (i=0; i<vdso64_pages; i++) { |
| struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); |
| struct page *upg = (vma && vma->vm_mm) ? |
| follow_page(vma->vm_mm, vma->vm_start + i*PAGE_SIZE, 0) |
| : NULL; |
| dump_one_vdso_page(pg, upg); |
| } |
| } |
| } |
| #endif /* DEBUG */ |
| |
| /* |
| * Keep a dummy vma_close for now, it will prevent VMA merging. |
| */ |
| static void vdso_vma_close(struct vm_area_struct * vma) |
| { |
| } |
| |
| /* |
| * Our nopage() function, maps in the actual vDSO kernel pages, they will |
| * be mapped read-only by do_no_page(), and eventually COW'ed, either |
| * right away for an initial write access, or by do_wp_page(). |
| */ |
| static struct page * vdso_vma_nopage(struct vm_area_struct * vma, |
| unsigned long address, int *type) |
| { |
| unsigned long offset = address - vma->vm_start; |
| struct page *pg; |
| void *vbase = test_thread_flag(TIF_32BIT) ? vdso32_kbase : vdso64_kbase; |
| |
| DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n", |
| current->comm, address, offset); |
| |
| if (address < vma->vm_start || address > vma->vm_end) |
| return NOPAGE_SIGBUS; |
| |
| /* |
| * Last page is systemcfg. |
| */ |
| if ((vma->vm_end - address) <= PAGE_SIZE) |
| pg = virt_to_page(_systemcfg); |
| else |
| pg = virt_to_page(vbase + offset); |
| |
| get_page(pg); |
| DBG(" ->page count: %d\n", page_count(pg)); |
| |
| return pg; |
| } |
| |
| static struct vm_operations_struct vdso_vmops = { |
| .close = vdso_vma_close, |
| .nopage = vdso_vma_nopage, |
| }; |
| |
| /* |
| * This is called from binfmt_elf, we create the special vma for the |
| * vDSO and insert it into the mm struct tree |
| */ |
| int arch_setup_additional_pages(struct linux_binprm *bprm, int executable_stack) |
| { |
| struct mm_struct *mm = current->mm; |
| struct vm_area_struct *vma; |
| unsigned long vdso_pages; |
| unsigned long vdso_base; |
| |
| if (test_thread_flag(TIF_32BIT)) { |
| vdso_pages = vdso32_pages; |
| vdso_base = VDSO32_MBASE; |
| } else { |
| vdso_pages = vdso64_pages; |
| vdso_base = VDSO64_MBASE; |
| } |
| |
| current->thread.vdso_base = 0; |
| |
| /* vDSO has a problem and was disabled, just don't "enable" it for the |
| * process |
| */ |
| if (vdso_pages == 0) |
| return 0; |
| |
| vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
| if (vma == NULL) |
| return -ENOMEM; |
| |
| memset(vma, 0, sizeof(*vma)); |
| |
| /* |
| * pick a base address for the vDSO in process space. We try to put it |
| * at vdso_base which is the "natural" base for it, but we might fail |
| * and end up putting it elsewhere. |
| */ |
| vdso_base = get_unmapped_area(NULL, vdso_base, |
| vdso_pages << PAGE_SHIFT, 0, 0); |
| if (vdso_base & ~PAGE_MASK) { |
| kmem_cache_free(vm_area_cachep, vma); |
| return (int)vdso_base; |
| } |
| |
| current->thread.vdso_base = vdso_base; |
| |
| vma->vm_mm = mm; |
| vma->vm_start = current->thread.vdso_base; |
| |
| /* |
| * the VMA size is one page more than the vDSO since systemcfg |
| * is mapped in the last one |
| */ |
| vma->vm_end = vma->vm_start + ((vdso_pages + 1) << PAGE_SHIFT); |
| |
| /* |
| * our vma flags don't have VM_WRITE so by default, the process isn't allowed |
| * to write those pages. |
| * gdb can break that with ptrace interface, and thus trigger COW on those |
| * pages but it's then your responsibility to never do that on the "data" page |
| * of the vDSO or you'll stop getting kernel updates and your nice userland |
| * gettimeofday will be totally dead. It's fine to use that for setting |
| * breakpoints in the vDSO code pages though |
| */ |
| vma->vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC | VM_RESERVED; |
| vma->vm_flags |= mm->def_flags; |
| vma->vm_page_prot = protection_map[vma->vm_flags & 0x7]; |
| vma->vm_ops = &vdso_vmops; |
| |
| down_write(&mm->mmap_sem); |
| if (insert_vm_struct(mm, vma)) { |
| up_write(&mm->mmap_sem); |
| kmem_cache_free(vm_area_cachep, vma); |
| return -ENOMEM; |
| } |
| mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
| up_write(&mm->mmap_sem); |
| |
| return 0; |
| } |
| |
| static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname, |
| unsigned long *size) |
| { |
| Elf32_Shdr *sechdrs; |
| unsigned int i; |
| char *secnames; |
| |
| /* Grab section headers and strings so we can tell who is who */ |
| sechdrs = (void *)ehdr + ehdr->e_shoff; |
| secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset; |
| |
| /* Find the section they want */ |
| for (i = 1; i < ehdr->e_shnum; i++) { |
| if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) { |
| if (size) |
| *size = sechdrs[i].sh_size; |
| return (void *)ehdr + sechdrs[i].sh_offset; |
| } |
| } |
| *size = 0; |
| return NULL; |
| } |
| |
| static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname, |
| unsigned long *size) |
| { |
| Elf64_Shdr *sechdrs; |
| unsigned int i; |
| char *secnames; |
| |
| /* Grab section headers and strings so we can tell who is who */ |
| sechdrs = (void *)ehdr + ehdr->e_shoff; |
| secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset; |
| |
| /* Find the section they want */ |
| for (i = 1; i < ehdr->e_shnum; i++) { |
| if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) { |
| if (size) |
| *size = sechdrs[i].sh_size; |
| return (void *)ehdr + sechdrs[i].sh_offset; |
| } |
| } |
| if (size) |
| *size = 0; |
| return NULL; |
| } |
| |
| static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib, const char *symname) |
| { |
| unsigned int i; |
| char name[32], *c; |
| |
| for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) { |
| if (lib->dynsym[i].st_name == 0) |
| continue; |
| strlcpy(name, lib->dynstr + lib->dynsym[i].st_name, 32); |
| c = strchr(name, '@'); |
| if (c) |
| *c = 0; |
| if (strcmp(symname, name) == 0) |
| return &lib->dynsym[i]; |
| } |
| return NULL; |
| } |
| |
| static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib, const char *symname) |
| { |
| unsigned int i; |
| char name[32], *c; |
| |
| for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) { |
| if (lib->dynsym[i].st_name == 0) |
| continue; |
| strlcpy(name, lib->dynstr + lib->dynsym[i].st_name, 32); |
| c = strchr(name, '@'); |
| if (c) |
| *c = 0; |
| if (strcmp(symname, name) == 0) |
| return &lib->dynsym[i]; |
| } |
| return NULL; |
| } |
| |
| /* Note that we assume the section is .text and the symbol is relative to |
| * the library base |
| */ |
| static unsigned long __init find_function32(struct lib32_elfinfo *lib, const char *symname) |
| { |
| Elf32_Sym *sym = find_symbol32(lib, symname); |
| |
| if (sym == NULL) { |
| printk(KERN_WARNING "vDSO32: function %s not found !\n", symname); |
| return 0; |
| } |
| return sym->st_value - VDSO32_LBASE; |
| } |
| |
| /* Note that we assume the section is .text and the symbol is relative to |
| * the library base |
| */ |
| static unsigned long __init find_function64(struct lib64_elfinfo *lib, const char *symname) |
| { |
| Elf64_Sym *sym = find_symbol64(lib, symname); |
| |
| if (sym == NULL) { |
| printk(KERN_WARNING "vDSO64: function %s not found !\n", symname); |
| return 0; |
| } |
| #ifdef VDS64_HAS_DESCRIPTORS |
| return *((u64 *)(vdso64_kbase + sym->st_value - VDSO64_LBASE)) - VDSO64_LBASE; |
| #else |
| return sym->st_value - VDSO64_LBASE; |
| #endif |
| } |
| |
| |
| static __init int vdso_do_find_sections(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64) |
| { |
| void *sect; |
| |
| /* |
| * Locate symbol tables & text section |
| */ |
| |
| v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize); |
| v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL); |
| if (v32->dynsym == NULL || v32->dynstr == NULL) { |
| printk(KERN_ERR "vDSO32: a required symbol section was not found\n"); |
| return -1; |
| } |
| sect = find_section32(v32->hdr, ".text", NULL); |
| if (sect == NULL) { |
| printk(KERN_ERR "vDSO32: the .text section was not found\n"); |
| return -1; |
| } |
| v32->text = sect - vdso32_kbase; |
| |
| v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize); |
| v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL); |
| if (v64->dynsym == NULL || v64->dynstr == NULL) { |
| printk(KERN_ERR "vDSO64: a required symbol section was not found\n"); |
| return -1; |
| } |
| sect = find_section64(v64->hdr, ".text", NULL); |
| if (sect == NULL) { |
| printk(KERN_ERR "vDSO64: the .text section was not found\n"); |
| return -1; |
| } |
| v64->text = sect - vdso64_kbase; |
| |
| return 0; |
| } |
| |
| static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64) |
| { |
| /* |
| * Find signal trampolines |
| */ |
| |
| vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64"); |
| vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32"); |
| vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32"); |
| } |
| |
| static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64) |
| { |
| Elf32_Sym *sym32; |
| Elf64_Sym *sym64; |
| |
| sym32 = find_symbol32(v32, "__kernel_datapage_offset"); |
| if (sym32 == NULL) { |
| printk(KERN_ERR "vDSO32: Can't find symbol __kernel_datapage_offset !\n"); |
| return -1; |
| } |
| *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) = |
| (vdso32_pages << PAGE_SHIFT) - (sym32->st_value - VDSO32_LBASE); |
| |
| sym64 = find_symbol64(v64, "__kernel_datapage_offset"); |
| if (sym64 == NULL) { |
| printk(KERN_ERR "vDSO64: Can't find symbol __kernel_datapage_offset !\n"); |
| return -1; |
| } |
| *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) = |
| (vdso64_pages << PAGE_SHIFT) - (sym64->st_value - VDSO64_LBASE); |
| |
| return 0; |
| } |
| |
| static int vdso_do_func_patch32(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64, |
| const char *orig, const char *fix) |
| { |
| Elf32_Sym *sym32_gen, *sym32_fix; |
| |
| sym32_gen = find_symbol32(v32, orig); |
| if (sym32_gen == NULL) { |
| printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig); |
| return -1; |
| } |
| sym32_fix = find_symbol32(v32, fix); |
| if (sym32_fix == NULL) { |
| printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix); |
| return -1; |
| } |
| sym32_gen->st_value = sym32_fix->st_value; |
| sym32_gen->st_size = sym32_fix->st_size; |
| sym32_gen->st_info = sym32_fix->st_info; |
| sym32_gen->st_other = sym32_fix->st_other; |
| sym32_gen->st_shndx = sym32_fix->st_shndx; |
| |
| return 0; |
| } |
| |
| static int vdso_do_func_patch64(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64, |
| const char *orig, const char *fix) |
| { |
| Elf64_Sym *sym64_gen, *sym64_fix; |
| |
| sym64_gen = find_symbol64(v64, orig); |
| if (sym64_gen == NULL) { |
| printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig); |
| return -1; |
| } |
| sym64_fix = find_symbol64(v64, fix); |
| if (sym64_fix == NULL) { |
| printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix); |
| return -1; |
| } |
| sym64_gen->st_value = sym64_fix->st_value; |
| sym64_gen->st_size = sym64_fix->st_size; |
| sym64_gen->st_info = sym64_fix->st_info; |
| sym64_gen->st_other = sym64_fix->st_other; |
| sym64_gen->st_shndx = sym64_fix->st_shndx; |
| |
| return 0; |
| } |
| |
| static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32, |
| struct lib64_elfinfo *v64) |
| { |
| u32 pvr; |
| int i; |
| |
| pvr = mfspr(SPRN_PVR); |
| for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) { |
| struct vdso_patch_def *patch = &vdso_patches[i]; |
| int match = (pvr & patch->pvr_mask) == patch->pvr_value; |
| |
| DBG("patch %d (mask: %x, pvr: %x) : %s\n", |
| i, patch->pvr_mask, patch->pvr_value, match ? "match" : "skip"); |
| |
| if (!match) |
| continue; |
| |
| DBG("replacing %s with %s...\n", patch->gen_name, patch->fix_name); |
| |
| /* |
| * Patch the 32 bits and 64 bits symbols. Note that we do not patch |
| * the "." symbol on 64 bits. It would be easy to do, but doesn't |
| * seem to be necessary, patching the OPD symbol is enough. |
| */ |
| vdso_do_func_patch32(v32, v64, patch->gen_name, patch->fix_name); |
| vdso_do_func_patch64(v32, v64, patch->gen_name, patch->fix_name); |
| } |
| |
| return 0; |
| } |
| |
| |
| static __init int vdso_setup(void) |
| { |
| struct lib32_elfinfo v32; |
| struct lib64_elfinfo v64; |
| |
| v32.hdr = vdso32_kbase; |
| v64.hdr = vdso64_kbase; |
| |
| if (vdso_do_find_sections(&v32, &v64)) |
| return -1; |
| |
| if (vdso_fixup_datapage(&v32, &v64)) |
| return -1; |
| |
| if (vdso_fixup_alt_funcs(&v32, &v64)) |
| return -1; |
| |
| vdso_setup_trampolines(&v32, &v64); |
| |
| return 0; |
| } |
| |
| void __init vdso_init(void) |
| { |
| int i; |
| |
| vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT; |
| vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT; |
| |
| DBG("vdso64_kbase: %p, 0x%x pages, vdso32_kbase: %p, 0x%x pages\n", |
| vdso64_kbase, vdso64_pages, vdso32_kbase, vdso32_pages); |
| |
| /* |
| * Initialize the vDSO images in memory, that is do necessary |
| * fixups of vDSO symbols, locate trampolines, etc... |
| */ |
| if (vdso_setup()) { |
| printk(KERN_ERR "vDSO setup failure, not enabled !\n"); |
| /* XXX should free pages here ? */ |
| vdso64_pages = vdso32_pages = 0; |
| return; |
| } |
| |
| /* Make sure pages are in the correct state */ |
| for (i = 0; i < vdso64_pages; i++) { |
| struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); |
| ClearPageReserved(pg); |
| get_page(pg); |
| } |
| for (i = 0; i < vdso32_pages; i++) { |
| struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); |
| ClearPageReserved(pg); |
| get_page(pg); |
| } |
| |
| get_page(virt_to_page(_systemcfg)); |
| } |
| |
| int in_gate_area_no_task(unsigned long addr) |
| { |
| return 0; |
| } |
| |
| int in_gate_area(struct task_struct *task, unsigned long addr) |
| { |
| return 0; |
| } |
| |
| struct vm_area_struct *get_gate_vma(struct task_struct *tsk) |
| { |
| return NULL; |
| } |
| |