[PATCH v2] x86/fpu: XRSTOR is expected to raise #GP

From: Jann Horn
Date: Tue Nov 27 2018 - 08:32:09 EST


commit 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess
fixups") incorrectly replaced the fixup entry for XSTATE_OP with a
user-#PF-only fixup. XRSTOR can also raise #GP if the xstate content is
invalid, and _ASM_EXTABLE_UA doesn't expect that.
Change this fixup back to _ASM_EXTABLE so that #GP gets fixed up.

Reported-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Fixes: 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess fixups")
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
---
arch/x86/include/asm/fpu/internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 5f7290e6e954..69dcdf195b61 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -226,7 +226,7 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
"3: movl $-2,%[err]\n\t" \
"jmp 2b\n\t" \
".popsection\n\t" \
- _ASM_EXTABLE_UA(1b, 3b) \
+ _ASM_EXTABLE(1b, 3b) \
: [err] "=r" (err) \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")
--
2.20.0.rc0.387.gc7a69e6b6c-goog