1 files changed, 122 insertions, 0 deletions
diff --git a/arch/parisc/kernel/vdso.c b/arch/parisc/kernel/vdso.c
new file mode 100644
index 000000000..47e5960a2
--- /dev/null
+++ b/arch/parisc/kernel/vdso.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (c) 2022 Helge Deller <deller@gmx.de>
+ *
+ *  based on arch/s390/kernel/vdso.c which is
+ *  Copyright IBM Corp. 2008
+ *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/elf.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/compat.h>
+#include <linux/nsproxy.h>
+#include <linux/time_namespace.h>
+#include <linux/random.h>
+
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/sections.h>
+#include <asm/vdso.h>
+#include <asm/cacheflush.h>
+
+extern char vdso32_start, vdso32_end;
+extern char vdso64_start, vdso64_end;
+
+static int vdso_mremap(const struct vm_special_mapping *sm,
+		       struct vm_area_struct *vma)
+{
+	current->mm->context.vdso_base = vma->vm_start;
+	return 0;
+}
+
+#ifdef CONFIG_64BIT
+static struct vm_special_mapping vdso64_mapping = {
+	.name = "[vdso]",
+	.mremap = vdso_mremap,
+};
+#endif
+
+static struct vm_special_mapping vdso32_mapping = {
+	.name = "[vdso]",
+	.mremap = vdso_mremap,
+};
+
+/*
+ * 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)
+{
+
+	unsigned long vdso_text_start, vdso_text_len, map_base;
+	struct vm_special_mapping *vdso_mapping;
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	int rc;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+#ifdef CONFIG_64BIT
+	if (!is_compat_task()) {
+		vdso_text_len = &vdso64_end - &vdso64_start;
+		vdso_mapping = &vdso64_mapping;
+	} else
+#endif
+	{
+		vdso_text_len = &vdso32_end - &vdso32_start;
+		vdso_mapping = &vdso32_mapping;
+	}
+
+	map_base = mm->mmap_base;
+	if (current->flags & PF_RANDOMIZE)
+		map_base -= prandom_u32_max(0x20) * PAGE_SIZE;
+
+	vdso_text_start = get_unmapped_area(NULL, map_base, vdso_text_len, 0, 0);
+
+	/* VM_MAYWRITE for COW so gdb can set breakpoints */
+	vma = _install_special_mapping(mm, vdso_text_start, vdso_text_len,
+				       VM_READ|VM_EXEC|
+				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+				       vdso_mapping);
+	if (IS_ERR(vma)) {
+		do_munmap(mm, vdso_text_start, PAGE_SIZE, NULL);
+		rc = PTR_ERR(vma);
+	} else {
+		current->mm->context.vdso_base = vdso_text_start;
+		rc = 0;
+	}
+
+	mmap_write_unlock(mm);
+	return rc;
+}
+
+static struct page ** __init vdso_setup_pages(void *start, void *end)
+{
+	int pages = (end - start) >> PAGE_SHIFT;
+	struct page **pagelist;
+	int i;
+
+	pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
+	if (!pagelist)
+		panic("%s: Cannot allocate page list for VDSO", __func__);
+	for (i = 0; i < pages; i++)
+		pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
+	return pagelist;
+}
+
+static int __init vdso_init(void)
+{
+#ifdef CONFIG_64BIT
+	vdso64_mapping.pages = vdso_setup_pages(&vdso64_start, &vdso64_end);
+#endif
+	if (IS_ENABLED(CONFIG_COMPAT) || !IS_ENABLED(CONFIG_64BIT))
+		vdso32_mapping.pages = vdso_setup_pages(&vdso32_start, &vdso32_end);
+	return 0;
+}
+arch_initcall(vdso_init);