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 0000000000..136c78f28f
--- /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_u32_below(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);