[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: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-i386/i387.h b/include/asm-i386/i387.h
index 7b1f011..bc1d6ed 100644
--- a/include/asm-i386/i387.h
+++ b/include/asm-i386/i387.h
@@ -58,13 +58,13 @@
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 */
