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authorAl Viro <viro@ftp.linux.org.uk>2011-08-18 20:06:39 +0100
committerRichard Weinberger <richard@nod.at>2011-11-02 14:15:05 +0100
commit5c48b108ecbf6505d929e64d50dace13ac2bdf34 (patch)
tree016904f84fbe05aa301c5cdfe712d90f6bb828fe /arch/x86/um/syscalls_64.c
parent7bbe7204e93734fe79d8aac3e08a7cb4624b5004 (diff)
um: take arch/um/sys-x86 to arch/x86/um
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/x86/um/syscalls_64.c')
-rw-r--r--arch/x86/um/syscalls_64.c102
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);
+}