Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / x86 / um / vdso / vma.c

diff --git a/kernel/arch/x86/um/vdso/vma.c b/kernel/arch/x86/um/vdso/vma.c
new file mode 100644 (file)
index 0000000..916cda4
--- /dev/null
+++ b/kernel/arch/x86/um/vdso/vma.c
@@ -0,0 +1,73 @@
+/*
+ * 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>
+
+static 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,
+               vdsop);
+
+       up_write(&mm->mmap_sem);
+
+       return err;
+}