x86-64, fpu: Fix %cs value in convert_from_fxsr()

While %ds still contains the userspace selector, %cs is KERNEL_CS at
this point.  Always get %cs from pt_regs even for the current task.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1283563039-3466-7-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 8216651..f3775f5 100644 (file)
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -389,19 +389,17 @@ convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
 #ifdef CONFIG_X86_64
        env->fip = fxsave->rip;
        env->foo = fxsave->rdp;
+       /*
+        * should be actually ds/cs at fpu exception time, but
+        * that information is not available in 64bit mode.
+        */
+       env->fcs = task_pt_regs(tsk)->cs;
        if (tsk == current) {
-               /*
-                * should be actually ds/cs at fpu exception time, but
-                * that information is not available in 64bit mode.
-                */
-               asm("mov %%ds, %[fos]" : [fos] "=r" (env->fos));
-               asm("mov %%cs, %[fcs]" : [fcs] "=r" (env->fcs));
+               savesegment(ds, env->fos);
        } else {
-               struct pt_regs *regs = task_pt_regs(tsk);
-
-               env->fos = 0xffff0000 | tsk->thread.ds;
-               env->fcs = regs->cs;
+               env->fos = tsk->thread.ds;
        }
+       env->fos |= 0xffff0000;
 #else
        env->fip = fxsave->fip;
        env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16);