1 files changed, 102 insertions, 0 deletions

diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c
new file mode 100644
index 000000000000..f3d82bb6e15a
--- /dev/null
+++ b/arch/x86/um/syscalls_64.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Copyright 2003 PathScale, Inc.
+ *
+ * Licensed under the GPL
+ */
+
+#include "linux/linkage.h"
+#include "linux/personality.h"
+#include "linux/utsname.h"
+#include "asm/prctl.h" /* XXX This should get the constants from libc */
+#include "asm/uaccess.h"
+#include "os.h"
+
+long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
+{
+        unsigned long *ptr = addr, tmp;
+        long ret;
+        int pid = task->mm->context.id.u.pid;
+
+        /*
+         * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
+         * be safe), we need to call arch_prctl on the host because
+         * setting %fs may result in something else happening (like a
+         * GDT or thread.fs being set instead).  So, we let the host
+         * fiddle the registers and thread struct and restore the
+         * registers afterwards.
+         *
+         * So, the saved registers are stored to the process (this
+         * needed because a stub may have been the last thing to run),
+         * arch_prctl is run on the host, then the registers are read
+         * back.
+         */
+        switch (code) {
+        case ARCH_SET_FS:
+        case ARCH_SET_GS:
+                ret = restore_registers(pid, &current->thread.regs.regs);
+                if (ret)
+                        return ret;
+                break;
+        case ARCH_GET_FS:
+        case ARCH_GET_GS:
+                /*
+                 * With these two, we read to a local pointer and
+                 * put_user it to the userspace pointer that we were
+                 * given.  If addr isn't valid (because it hasn't been
+                 * faulted in or is just bogus), we want put_user to
+                 * fault it in (or return -EFAULT) instead of having
+                 * the host return -EFAULT.
+                 */
+                ptr = &tmp;
+        }
+
+        ret = os_arch_prctl(pid, code, ptr);
+        if (ret)
+                return ret;
+
+        switch (code) {
+        case ARCH_SET_FS:
+                current->thread.arch.fs = (unsigned long) ptr;
+                ret = save_registers(pid, &current->thread.regs.regs);
+                break;
+        case ARCH_SET_GS:
+                ret = save_registers(pid, &current->thread.regs.regs);
+                break;
+        case ARCH_GET_FS:
+                ret = put_user(tmp, addr);
+                break;
+        case ARCH_GET_GS:
+                ret = put_user(tmp, addr);
+                break;
+        }
+
+        return ret;
+}
+
+long sys_arch_prctl(int code, unsigned long addr)
+{
+        return arch_prctl(current, code, (unsigned long __user *) addr);
+}
+
+long sys_clone(unsigned long clone_flags, unsigned long newsp,
+               void __user *parent_tid, void __user *child_tid)
+{
+        long ret;
+
+        if (!newsp)
+                newsp = UPT_SP(&current->thread.regs.regs);
+        current->thread.forking = 1;
+        ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
+                      child_tid);
+        current->thread.forking = 0;
+        return ret;
+}
+
+void arch_switch_to(struct task_struct *to)
+{
+        if ((to->thread.arch.fs == 0) || (to->mm == NULL))
+                return;
+
+        arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
+}