1 files changed, 150 insertions, 0 deletions

diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
new file mode 100644
index 000000000000..075d6cc1a2d7
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -0,0 +1,150 @@
+/*
+ * arch/sh/kernel/vsyscall.c
+ *
+ *  Copyright (C) 2006 Paul Mundt
+ *
+ * vDSO randomization
+ * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <linux/module.h>
+#include <linux/elf.h>
+
+/*
+ * Should the kernel map a VDSO page into processes and pass its
+ * address down to glibc upon exec()?
+ */
+unsigned int __read_mostly vdso_enabled = 1;
+EXPORT_SYMBOL_GPL(vdso_enabled);
+
+static int __init vdso_setup(char *s)
+{
+        vdso_enabled = simple_strtoul(s, NULL, 0);
+        return 1;
+}
+__setup("vdso=", vdso_setup);
+
+/*
+ * These symbols are defined by vsyscall.o to mark the bounds
+ * of the ELF DSO images included therein.
+ */
+extern const char vsyscall_trapa_start, vsyscall_trapa_end;
+static void *syscall_page;
+
+int __init vsyscall_init(void)
+{
+        syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+
+        /*
+         * XXX: Map this page to a fixmap entry if we get around
+         * to adding the page to ELF core dumps
+         */
+
+        memcpy(syscall_page,
+               &vsyscall_trapa_start,
+               &vsyscall_trapa_end - &vsyscall_trapa_start);
+
+        return 0;
+}
+
+static struct page *syscall_vma_nopage(struct vm_area_struct *vma,
+                                       unsigned long address, int *type)
+{
+        unsigned long offset = address - vma->vm_start;
+        struct page *page;
+
+        if (address < vma->vm_start || address > vma->vm_end)
+                return NOPAGE_SIGBUS;
+
+        page = virt_to_page(syscall_page + offset);
+
+        get_page(page);
+
+        return page;
+}
+
+/* Prevent VMA merging */
+static void syscall_vma_close(struct vm_area_struct *vma)
+{
+}
+
+static struct vm_operations_struct syscall_vm_ops = {
+        .nopage = syscall_vma_nopage,
+        .close  = syscall_vma_close,
+};
+
+/* Setup a VMA at program startup for the vsyscall page */
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+                                int executable_stack)
+{
+        struct vm_area_struct *vma;
+        struct mm_struct *mm = current->mm;
+        unsigned long addr;
+        int ret;
+
+        down_write(&mm->mmap_sem);
+        addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
+        if (IS_ERR_VALUE(addr)) {
+                ret = addr;
+                goto up_fail;
+        }
+
+        vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL);
+        if (!vma) {
+                ret = -ENOMEM;
+                goto up_fail;
+        }
+
+        vma->vm_start = addr;
+        vma->vm_end = addr + PAGE_SIZE;
+        /* MAYWRITE to allow gdb to COW and set breakpoints */
+        vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
+        vma->vm_flags |= mm->def_flags;
+        vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+        vma->vm_ops = &syscall_vm_ops;
+        vma->vm_mm = mm;
+
+        ret = insert_vm_struct(mm, vma);
+        if (unlikely(ret)) {
+                kmem_cache_free(vm_area_cachep, vma);
+                goto up_fail;
+        }
+
+        current->mm->context.vdso = (void *)addr;
+
+        mm->total_vm++;
+up_fail:
+        up_write(&mm->mmap_sem);
+        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]";
+
+        return NULL;
+}
+
+struct vm_area_struct *get_gate_vma(struct task_struct *task)
+{
+        return NULL;
+}
+
+int in_gate_area(struct task_struct *task, unsigned long address)
+{
+        return 0;
+}
+
+int in_gate_area_no_task(unsigned long address)
+{
+        return 0;
+}