1 files changed, 268 insertions, 0 deletions
diff --git a/arch/sparc/vdso/vma.c b/arch/sparc/vdso/vma.c
new file mode 100644
index 000000000000..0a6f50098e23
--- /dev/null
+++ b/arch/sparc/vdso/vma.c
@@ -0,0 +1,268 @@
+/*
+ * Set up the VMAs to tell the VM about the vDSO.
+ * Copyright 2007 Andi Kleen, SUSE Labs.
+ * Subject to the GPL, v.2
+ */
+
+/*
+ * 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/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;
+
+#define	SAVE_INSTR_SIZE	4
+
+/*
+ * 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)
+{
+	int i;
+	struct page *dp, **dpp = NULL;
+	int dnpages = 0;
+	struct page *cp, **cpp = NULL;
+	int cnpages = (image->size) / PAGE_SIZE;
+
+	/*
+	 * 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;
+
+	if (vdso_fix_stick) {
+		/*
+		 * If the system uses %tick instead of %stick, patch the VDSO
+		 * with instruction reading %tick instead of %stick.
+		 */
+		unsigned int j, k = SAVE_INSTR_SIZE;
+		unsigned char *data = image->data;
+
+		for (j = image->sym_vread_tick_patch_start;
+		     j < image->sym_vread_tick_patch_end; j++) {
+
+			data[image->sym_vread_tick + k] = data[j];
+			k++;
+		}
+	}
+
+	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);
+	if (err)
+		return err;
+#endif
+
+#ifdef CONFIG_COMPAT
+	err = init_vdso_image(&vdso_image_32_builtin, &vdso_mapping32);
+#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;
+
+	down_write(&mm->mmap_sem);
+
+	/*
+	 * 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;
+
+	up_write(&mm->mmap_sem);
+	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);
+	vdso_enabled = val;
+	return err;
+}
+__setup("vdso=", vdso_setup);