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Diffstat (limited to '')
| -rw-r--r-- | arch/sparc/vdso/vma.c | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/arch/sparc/vdso/vma.c b/arch/sparc/vdso/vma.c new file mode 100644 index 000000000..cc19e09b0 --- /dev/null +++ b/arch/sparc/vdso/vma.c @@ -0,0 +1,457 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Set up the VMAs to tell the VM about the vDSO. + * Copyright 2007 Andi Kleen, SUSE Labs. + */ + +/* + * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved. + */ + +#include <linux/mm.h> +#include <linux/err.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/linkage.h> +#include <linux/random.h> +#include <linux/elf.h> +#include <asm/cacheflush.h> +#include <asm/spitfire.h> +#include <asm/vdso.h> +#include <asm/vvar.h> +#include <asm/page.h> + +unsigned int __read_mostly vdso_enabled = 1; + +static struct vm_special_mapping vvar_mapping = { + .name = "[vvar]" +}; + +#ifdef CONFIG_SPARC64 +static struct vm_special_mapping vdso_mapping64 = { + .name = "[vdso]" +}; +#endif + +#ifdef CONFIG_COMPAT +static struct vm_special_mapping vdso_mapping32 = { + .name = "[vdso]" +}; +#endif + +struct vvar_data *vvar_data; + +struct vdso_elfinfo32 { + Elf32_Ehdr *hdr; + Elf32_Sym *dynsym; + unsigned long dynsymsize; + const char *dynstr; + unsigned long text; +}; + +struct vdso_elfinfo64 { + Elf64_Ehdr *hdr; + Elf64_Sym *dynsym; + unsigned long dynsymsize; + const char *dynstr; + unsigned long text; +}; + +struct vdso_elfinfo { + union { + struct vdso_elfinfo32 elf32; + struct vdso_elfinfo64 elf64; + } u; +}; + +static void *one_section64(struct vdso_elfinfo64 *e, const char *name, + unsigned long *size) +{ + const char *snames; + Elf64_Shdr *shdrs; + unsigned int i; + + shdrs = (void *)e->hdr + e->hdr->e_shoff; + snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset; + for (i = 1; i < e->hdr->e_shnum; i++) { + if (!strcmp(snames+shdrs[i].sh_name, name)) { + if (size) + *size = shdrs[i].sh_size; + return (void *)e->hdr + shdrs[i].sh_offset; + } + } + return NULL; +} + +static int find_sections64(const struct vdso_image *image, struct vdso_elfinfo *_e) +{ + struct vdso_elfinfo64 *e = &_e->u.elf64; + + e->hdr = image->data; + e->dynsym = one_section64(e, ".dynsym", &e->dynsymsize); + e->dynstr = one_section64(e, ".dynstr", NULL); + + if (!e->dynsym || !e->dynstr) { + pr_err("VDSO64: Missing symbol sections.\n"); + return -ENODEV; + } + return 0; +} + +static Elf64_Sym *find_sym64(const struct vdso_elfinfo64 *e, const char *name) +{ + unsigned int i; + + for (i = 0; i < (e->dynsymsize / sizeof(Elf64_Sym)); i++) { + Elf64_Sym *s = &e->dynsym[i]; + if (s->st_name == 0) + continue; + if (!strcmp(e->dynstr + s->st_name, name)) + return s; + } + return NULL; +} + +static int patchsym64(struct vdso_elfinfo *_e, const char *orig, + const char *new) +{ + struct vdso_elfinfo64 *e = &_e->u.elf64; + Elf64_Sym *osym = find_sym64(e, orig); + Elf64_Sym *nsym = find_sym64(e, new); + + if (!nsym || !osym) { + pr_err("VDSO64: Missing symbols.\n"); + return -ENODEV; + } + osym->st_value = nsym->st_value; + osym->st_size = nsym->st_size; + osym->st_info = nsym->st_info; + osym->st_other = nsym->st_other; + osym->st_shndx = nsym->st_shndx; + + return 0; +} + +static void *one_section32(struct vdso_elfinfo32 *e, const char *name, + unsigned long *size) +{ + const char *snames; + Elf32_Shdr *shdrs; + unsigned int i; + + shdrs = (void *)e->hdr + e->hdr->e_shoff; + snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset; + for (i = 1; i < e->hdr->e_shnum; i++) { + if (!strcmp(snames+shdrs[i].sh_name, name)) { + if (size) + *size = shdrs[i].sh_size; + return (void *)e->hdr + shdrs[i].sh_offset; + } + } + return NULL; +} + +static int find_sections32(const struct vdso_image *image, struct vdso_elfinfo *_e) +{ + struct vdso_elfinfo32 *e = &_e->u.elf32; + + e->hdr = image->data; + e->dynsym = one_section32(e, ".dynsym", &e->dynsymsize); + e->dynstr = one_section32(e, ".dynstr", NULL); + + if (!e->dynsym || !e->dynstr) { + pr_err("VDSO32: Missing symbol sections.\n"); + return -ENODEV; + } + return 0; +} + +static Elf32_Sym *find_sym32(const struct vdso_elfinfo32 *e, const char *name) +{ + unsigned int i; + + for (i = 0; i < (e->dynsymsize / sizeof(Elf32_Sym)); i++) { + Elf32_Sym *s = &e->dynsym[i]; + if (s->st_name == 0) + continue; + if (!strcmp(e->dynstr + s->st_name, name)) + return s; + } + return NULL; +} + +static int patchsym32(struct vdso_elfinfo *_e, const char *orig, + const char *new) +{ + struct vdso_elfinfo32 *e = &_e->u.elf32; + Elf32_Sym *osym = find_sym32(e, orig); + Elf32_Sym *nsym = find_sym32(e, new); + + if (!nsym || !osym) { + pr_err("VDSO32: Missing symbols.\n"); + return -ENODEV; + } + osym->st_value = nsym->st_value; + osym->st_size = nsym->st_size; + osym->st_info = nsym->st_info; + osym->st_other = nsym->st_other; + osym->st_shndx = nsym->st_shndx; + + return 0; +} + +static int find_sections(const struct vdso_image *image, struct vdso_elfinfo *e, + bool elf64) +{ + if (elf64) + return find_sections64(image, e); + else + return find_sections32(image, e); +} + +static int patch_one_symbol(struct vdso_elfinfo *e, const char *orig, + const char *new_target, bool elf64) +{ + if (elf64) + return patchsym64(e, orig, new_target); + else + return patchsym32(e, orig, new_target); +} + +static int stick_patch(const struct vdso_image *image, struct vdso_elfinfo *e, bool elf64) +{ + int err; + + err = find_sections(image, e, elf64); + if (err) + return err; + + err = patch_one_symbol(e, + "__vdso_gettimeofday", + "__vdso_gettimeofday_stick", elf64); + if (err) + return err; + + return patch_one_symbol(e, + "__vdso_clock_gettime", + "__vdso_clock_gettime_stick", elf64); + return 0; +} + +/* + * Allocate pages for the vdso and vvar, and copy in the vdso text from the + * kernel image. + */ +int __init init_vdso_image(const struct vdso_image *image, + struct vm_special_mapping *vdso_mapping, bool elf64) +{ + int cnpages = (image->size) / PAGE_SIZE; + struct page *dp, **dpp = NULL; + struct page *cp, **cpp = NULL; + struct vdso_elfinfo ei; + int i, dnpages = 0; + + if (tlb_type != spitfire) { + int err = stick_patch(image, &ei, elf64); + if (err) + return err; + } + + /* + * First, the vdso text. This is initialied data, an integral number of + * pages long. + */ + if (WARN_ON(image->size % PAGE_SIZE != 0)) + goto oom; + + cpp = kcalloc(cnpages, sizeof(struct page *), GFP_KERNEL); + vdso_mapping->pages = cpp; + + if (!cpp) + goto oom; + + for (i = 0; i < cnpages; i++) { + cp = alloc_page(GFP_KERNEL); + if (!cp) + goto oom; + cpp[i] = cp; + copy_page(page_address(cp), image->data + i * PAGE_SIZE); + } + + /* + * Now the vvar page. This is uninitialized data. + */ + + if (vvar_data == NULL) { + dnpages = (sizeof(struct vvar_data) / PAGE_SIZE) + 1; + if (WARN_ON(dnpages != 1)) + goto oom; + dpp = kcalloc(dnpages, sizeof(struct page *), GFP_KERNEL); + vvar_mapping.pages = dpp; + + if (!dpp) + goto oom; + + dp = alloc_page(GFP_KERNEL); + if (!dp) + goto oom; + + dpp[0] = dp; + vvar_data = page_address(dp); + memset(vvar_data, 0, PAGE_SIZE); + + vvar_data->seq = 0; + } + + return 0; + oom: + if (cpp != NULL) { + for (i = 0; i < cnpages; i++) { + if (cpp[i] != NULL) + __free_page(cpp[i]); + } + kfree(cpp); + vdso_mapping->pages = NULL; + } + + if (dpp != NULL) { + for (i = 0; i < dnpages; i++) { + if (dpp[i] != NULL) + __free_page(dpp[i]); + } + kfree(dpp); + vvar_mapping.pages = NULL; + } + + pr_warn("Cannot allocate vdso\n"); + vdso_enabled = 0; + return -ENOMEM; +} + +static int __init init_vdso(void) +{ + int err = 0; +#ifdef CONFIG_SPARC64 + err = init_vdso_image(&vdso_image_64_builtin, &vdso_mapping64, true); + if (err) + return err; +#endif + +#ifdef CONFIG_COMPAT + err = init_vdso_image(&vdso_image_32_builtin, &vdso_mapping32, false); +#endif + return err; + +} +subsys_initcall(init_vdso); + +struct linux_binprm; + +/* Shuffle the vdso up a bit, randomly. */ +static unsigned long vdso_addr(unsigned long start, unsigned int len) +{ + unsigned int offset; + + /* This loses some more bits than a modulo, but is cheaper */ + offset = get_random_int() & (PTRS_PER_PTE - 1); + return start + (offset << PAGE_SHIFT); +} + +static int map_vdso(const struct vdso_image *image, + struct vm_special_mapping *vdso_mapping) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long text_start, addr = 0; + int ret = 0; + + mmap_write_lock(mm); + + /* + * First, get an unmapped region: then randomize it, and make sure that + * region is free. + */ + if (current->flags & PF_RANDOMIZE) { + addr = get_unmapped_area(NULL, 0, + image->size - image->sym_vvar_start, + 0, 0); + if (IS_ERR_VALUE(addr)) { + ret = addr; + goto up_fail; + } + addr = vdso_addr(addr, image->size - image->sym_vvar_start); + } + addr = get_unmapped_area(NULL, addr, + image->size - image->sym_vvar_start, 0, 0); + if (IS_ERR_VALUE(addr)) { + ret = addr; + goto up_fail; + } + + text_start = addr - image->sym_vvar_start; + current->mm->context.vdso = (void __user *)text_start; + + /* + * MAYWRITE to allow gdb to COW and set breakpoints + */ + vma = _install_special_mapping(mm, + text_start, + image->size, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, + vdso_mapping); + + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto up_fail; + } + + vma = _install_special_mapping(mm, + addr, + -image->sym_vvar_start, + VM_READ|VM_MAYREAD, + &vvar_mapping); + + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + do_munmap(mm, text_start, image->size, NULL); + } + +up_fail: + if (ret) + current->mm->context.vdso = NULL; + + mmap_write_unlock(mm); + return ret; +} + +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + + if (!vdso_enabled) + return 0; + +#if defined CONFIG_COMPAT + if (!(is_32bit_task())) + return map_vdso(&vdso_image_64_builtin, &vdso_mapping64); + else + return map_vdso(&vdso_image_32_builtin, &vdso_mapping32); +#else + return map_vdso(&vdso_image_64_builtin, &vdso_mapping64); +#endif + +} + +static __init int vdso_setup(char *s) +{ + int err; + unsigned long val; + + err = kstrtoul(s, 10, &val); + if (err) + return err; + vdso_enabled = val; + return 0; +} +__setup("vdso=", vdso_setup); |