[PATCH] i386: fix broken FP exception handling

The FXSAVE information leak patch introduced a bug in FP exception
handling: it clears FP exceptions only when there are already
none outstanding.  Mikael Pettersson reported that causes problems
with the Erlang runtime and has tested this fix.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Acked-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/asm-i386/i387.h b/include/asm-i386/i387.h
index 7b1f01191e7063df3ab056dfdb17e6de0bcd828f..bc1d6edae1edfe73b9d77c318fea69b9d0951328 100644 (file)
--- a/include/asm-i386/i387.h
+++ b/include/asm-i386/i387.h
@@ -58,13 +58,13 @@ static inline void __save_init_fpu( struct task_struct *tsk )
        alternative_input(
                "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
                "fxsave %[fx]\n"
-               "bt $7,%[fsw] ; jc 1f ; fnclex\n1:",
+               "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
                X86_FEATURE_FXSR,
                [fx] "m" (tsk->thread.i387.fxsave),
                [fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory");
        /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
           is pending.  Clear the x87 state here by setting it to fixed
-          values. __per_cpu_offset[0] is a random variable that should be in L1 */
+          values. safe_address is a random variable that should be in L1 */
        alternative_input(
                GENERIC_NOP8 GENERIC_NOP2,
                "emms\n\t"              /* clear stack tags */