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-rw-r--r--arch/csky/kernel/vdso.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/csky/kernel/vdso.c b/arch/csky/kernel/vdso.c
new file mode 100644
index 0000000000..16c20d64d1
--- /dev/null
+++ b/arch/csky/kernel/vdso.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/binfmts.h>
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include <asm/page.h>
+#ifdef 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;
+
+ mmap_write_lock(mm);
+ 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;
+}