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authorSuresh Siddha <suresh.b.siddha@intel.com>2008-05-07 12:09:52 -0700
committerThomas Gleixner <tglx@linutronix.de>2008-05-10 19:31:45 +0200
commitfd3c3ed5d1e3ceb37635cbe6d220ab94aae0781d (patch)
tree67cc2a950e670e5362173efd88ea6ded708b7e6c /arch/x86
parent0646153921892cc7a81320a6920beaca06b3e9f0 (diff)
x86: fix fpu restore from sig return
If the task never used fpu, initialize the fpu before restoring the FP state from the signal handler context. This will allocate the fpu state, if the task never needed it before. Reported-and-bisected-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Tested-by: Eric Sesterhenn <snakebyte@gmx.de> Cc: Frederik Deweerdt <deweerdt@free.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/i387.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index db6839b53195..e03cc952f233 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -450,7 +450,6 @@ static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
{
struct task_struct *tsk = current;
- clear_fpu(tsk);
return __copy_from_user(&tsk->thread.xstate->fsave, buf,
sizeof(struct i387_fsave_struct));
}
@@ -461,7 +460,6 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
struct user_i387_ia32_struct env;
int err;
- clear_fpu(tsk);
err = __copy_from_user(&tsk->thread.xstate->fxsave, &buf->_fxsr_env[0],
sizeof(struct i387_fxsave_struct));
/* mxcsr reserved bits must be masked to zero for security reasons */
@@ -478,6 +476,16 @@ int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
int err;
if (HAVE_HWFP) {
+ struct task_struct *tsk = current;
+
+ clear_fpu(tsk);
+
+ if (!used_math()) {
+ err = init_fpu(tsk);
+ if (err)
+ return err;
+ }
+
if (cpu_has_fxsr)
err = restore_i387_fxsave(buf);
else