Messages in this thread Patch in this message | | | From | Brian Gerst <> | Subject | [PATCH 06/11] x86-64: Fix %cs value in convert_from_fxsr() | Date | Sat, 28 Aug 2010 12:04:33 -0400 |
| |
While %ds still contains the userspace selector, %cs is KERNEL_CS at this point. Always get %cs from pt_regs.
It actually is possible to get the correct segments for compat tasks, but that involves using the [f]xsave instruction without a REX.W prefix.
Signed-off-by: Brian Gerst <brgerst@gmail.com> --- arch/x86/kernel/i387.c | 18 ++++++++---------- 1 files changed, 8 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index c795675..b1a732d 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -383,19 +383,17 @@ 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); -- 1.7.2.2
| |