summaryrefslogtreecommitdiffstats
path: root/arch/sparc/vdso/vma.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sparc/vdso/vma.c')
-rw-r--r--arch/sparc/vdso/vma.c457
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..ae9a86cb6
--- /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 = prandom_u32_max(PTRS_PER_PTE);
+ 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);