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Diffstat (limited to 'arch/x86/um/vdso/vma.c')
-rw-r--r--arch/x86/um/vdso/vma.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
new file mode 100644
index 00000000000..91f4ec9a0a5
--- /dev/null
+++ b/arch/x86/um/vdso/vma.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+#include <linux/init.h>
+
+unsigned int __read_mostly vdso_enabled = 1;
+unsigned long um_vdso_addr;
+
+extern unsigned long task_size;
+extern char vdso_start[], vdso_end[];
+
+static struct page **vdsop;
+
+static int __init init_vdso(void)
+{
+ struct page *um_vdso;
+
+ BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
+
+ um_vdso_addr = task_size - PAGE_SIZE;
+
+ vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
+ if (!vdsop)
+ goto oom;
+
+ um_vdso = alloc_page(GFP_KERNEL);
+ if (!um_vdso) {
+ kfree(vdsop);
+
+ goto oom;
+ }
+
+ copy_page(page_address(um_vdso), vdso_start);
+ *vdsop = um_vdso;
+
+ return 0;
+
+oom:
+ printk(KERN_ERR "Cannot allocate vdso\n");
+ vdso_enabled = 0;
+
+ return -ENOMEM;
+}
+subsys_initcall(init_vdso);
+
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+ int err;
+ struct mm_struct *mm = current->mm;
+
+ if (!vdso_enabled)
+ return 0;
+
+ down_write(&mm->mmap_sem);
+
+ err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
+ VM_READ|VM_EXEC|
+ VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+ VM_ALWAYSDUMP,
+ vdsop);
+
+ up_write(&mm->mmap_sem);
+
+ return err;
+}