From f8483988cadd7dd22de928db29ed3bcbe02faf78 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Wed, 25 Feb 2015 13:08:05 +0000 Subject: [PATCH] MIPS: lose_fpu(): Disable FPU when MSA enabled 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: 33c771ba5c5d ("MIPS: save/disable MSA in lose_fpu") Signed-off-by: James Hogan Cc: Ralf Baechle Cc: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9323/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/fpu.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h index dd083e999b08..9f26b079cc6a 100644 --- a/arch/mips/include/asm/fpu.h +++ b/arch/mips/include/asm/fpu.h @@ -170,6 +170,7 @@ 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);