MIPS: Tidy up FPU context switching

Rather than saving the scalar FP or vector context in the assembly
resume function, reuse the existing C code we have in fpu.h to do
exactly that. This reduces duplication, results in a much easier to read
resume function & should allow the compiler to optimise out more MSA
code due to is_msa_enabled()/cpu_has_msa being known-zero at compile
time for kernels without MSA support.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10830/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 13 insertions, 8 deletions

diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h
index 1b0625189835..9cbf383b8834 100644
--- a/arch/mips/include/asm/fpu.h
+++ b/arch/mips/include/asm/fpu.h
@@ -164,25 +164,30 @@ static inline int own_fpu(int restore)
 	return ret;
 }
 
-static inline void lose_fpu(int save)
+static inline void lose_fpu_inatomic(int save, struct task_struct *tsk)
 {
-	preempt_disable();
 	if (is_msa_enabled()) {
 		if (save) {
-			save_msa(current);
-			current->thread.fpu.fcr31 =
+			save_msa(tsk);
+			tsk->thread.fpu.fcr31 =
 					read_32bit_cp1_register(CP1_STATUS);
 		}
 		disable_msa();
-		clear_thread_flag(TIF_USEDMSA);
+		clear_tsk_thread_flag(tsk, TIF_USEDMSA);
 		__disable_fpu();
 	} else if (is_fpu_owner()) {
 		if (save)
-			_save_fp(current);
+			_save_fp(tsk);
 		__disable_fpu();
 	}
-	KSTK_STATUS(current) &= ~ST0_CU1;
-	clear_thread_flag(TIF_USEDFPU);
+	KSTK_STATUS(tsk) &= ~ST0_CU1;
+	clear_tsk_thread_flag(tsk, TIF_USEDFPU);
+}
+
+static inline void lose_fpu(int save)
+{
+	preempt_disable();
+	lose_fpu_inatomic(save, current);
 	preempt_enable();
 }