Commit 00f1187a authored by James Hogan's avatar James Hogan Committed by Sasha Levin

MIPS: lose_fpu(): Disable FPU when MSA enabled

[ Upstream commit f8483988 ]

The lose_fpu() function only disables the FPU in CP0_Status.CU1 if the
FPU is in use and MSA isn't enabled.

This isn't necessarily a problem because KSTK_STATUS(current), the
version of CP0_Status stored on the kernel stack on entry from user
mode, does always get updated and gets restored when returning to user
mode, but I don't think it was intended, and it is inconsistent with the
case of only the FPU being in use. Sometimes leaving the FPU enabled may
also mask kernel bugs where FPU operations are executed when the FPU
might not be enabled.

So lets disable the FPU in the MSA case too.

Fixes: 33c771ba ("MIPS: save/disable MSA in lose_fpu")
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9323/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 707ff225
......@@ -150,6 +150,7 @@ static inline void lose_fpu(int save)
}
disable_msa();
clear_thread_flag(TIF_USEDMSA);
__disable_fpu();
} else if (is_fpu_owner()) {
if (save)
_save_fp(current);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment