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authorChuck Ebbert <76306.1226@compuserve.com>2006-04-29 14:07:49 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-29 17:13:16 -0400
commit543f2a3382bd7abd7380903518c61f00c7c87577 (patch)
treeca6dff499b29f40b5ff62aaaed48def6e4c81016
parent693f7d362055261882659475d2ef022e32edbff1 (diff)
[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>
-rw-r--r--include/asm-i386/i387.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/asm-i386/i387.h b/include/asm-i386/i387.h
index 7b1f01191e70..bc1d6edae1ed 100644
--- 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 )
58 alternative_input( 58 alternative_input(
59 "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4, 59 "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
60 "fxsave %[fx]\n" 60 "fxsave %[fx]\n"
61 "bt $7,%[fsw] ; jc 1f ; fnclex\n1:", 61 "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
62 X86_FEATURE_FXSR, 62 X86_FEATURE_FXSR,
63 [fx] "m" (tsk->thread.i387.fxsave), 63 [fx] "m" (tsk->thread.i387.fxsave),
64 [fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory"); 64 [fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory");
65 /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception 65 /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
66 is pending. Clear the x87 state here by setting it to fixed 66 is pending. Clear the x87 state here by setting it to fixed
67 values. __per_cpu_offset[0] is a random variable that should be in L1 */ 67 values. safe_address is a random variable that should be in L1 */
68 alternative_input( 68 alternative_input(
69 GENERIC_NOP8 GENERIC_NOP2, 69 GENERIC_NOP8 GENERIC_NOP2,
70 "emms\n\t" /* clear stack tags */ 70 "emms\n\t" /* clear stack tags */