1 files changed, 113 insertions, 0 deletions
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
new file mode 100644
index 000000000..73d45931a
--- /dev/null
+++ b/arch/riscv/kernel/vdso.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ * Copyright (C) 2012 ARM Limited
+ * Copyright (C) 2015 Regents of the University of California
+ */
+
+#include <linux/elf.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/binfmts.h>
+#include <linux/err.h>
+#include <asm/page.h>
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+#include <vdso/datapage.h>
+#else
+#include <asm/vdso.h>
+#endif
+
+extern char vdso_start[], vdso_end[];
+
+static unsigned int vdso_pages;
+static struct page **vdso_pagelist;
+
+/*
+ * The vDSO data page.
+ */
+static union {
+	struct vdso_data	data;
+	u8			page[PAGE_SIZE];
+} vdso_data_store __page_aligned_data;
+struct vdso_data *vdso_data = &vdso_data_store.data;
+
+static int __init vdso_init(void)
+{
+	unsigned int i;
+
+	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
+	vdso_pagelist =
+		kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
+	if (unlikely(vdso_pagelist == NULL)) {
+		pr_err("vdso: pagelist allocation failed\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < vdso_pages; i++) {
+		struct page *pg;
+
+		pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
+		vdso_pagelist[i] = pg;
+	}
+	vdso_pagelist[i] = virt_to_page(vdso_data);
+
+	return 0;
+}
+arch_initcall(vdso_init);
+
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+	int uses_interp)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long vdso_base, vdso_len;
+	int ret;
+
+	vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
+	if (IS_ERR_VALUE(vdso_base)) {
+		ret = vdso_base;
+		goto end;
+	}
+
+	/*
+	 * Put vDSO base into mm struct. We need to do this before calling
+	 * install_special_mapping or the perf counter mmap tracking code
+	 * will fail to recognise it as a vDSO (since arch_vma_name fails).
+	 */
+	mm->context.vdso = (void *)vdso_base;
+
+	ret =
+	   install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
+		(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
+		vdso_pagelist);
+
+	if (unlikely(ret)) {
+		mm->context.vdso = NULL;
+		goto end;
+	}
+
+	vdso_base += (vdso_pages << PAGE_SHIFT);
+	ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
+		(VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
+
+	if (unlikely(ret))
+		mm->context.vdso = NULL;
+end:
+	mmap_write_unlock(mm);
+	return ret;
+}
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+	if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
+		return "[vdso]";
+	if (vma->vm_mm && (vma->vm_start ==
+			   (long)vma->vm_mm->context.vdso + PAGE_SIZE))
+		return "[vdso_data]";
+	return NULL;
+}