This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / sh / kernel / vsyscall / vsyscall.c

diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
new file mode 100644 (file)
index 0000000..e1c78ca
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -0,0 +1,151 @@
+/*
+ * 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>
+#include <linux/vs_memory.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, GFP_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;
+
+       vx_vmpages_inc(mm);
+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;
+}