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Commit bfcdf130 authored by Huacai Chen's avatar Huacai Chen Committed by Ralf Baechle
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MIPS: Loongson: Fix COP2 usage for preemptible kernel 



In preemptible kernel, only TIF_USEDFPU flag is reliable to distinguish
whether _init_fpu()/_restore_fp() is needed. Because the value of the
CP0_Status.CU1 isn't changed during preemption.

V2: Fix coding style.

Signed-off-by: default avatarHuacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7515/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent bbbf6d87

arch/mips/loongson/loongson-3/cop2-ex.c

+4 −4
Original line number Diff line number Diff line
@@ -22,13 +22,13 @@ 
static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,

	void *data)

{

	int fpu_enabled;

	int fpu_owned;

	int fr = !test_thread_flag(TIF_32BIT_FPREGS);



	switch (action) {

	case CU2_EXCEPTION:

		preempt_disable();

		fpu_enabled = read_c0_status() & ST0_CU1;

		fpu_owned = __is_fpu_owner();

		if (!fr)

			set_c0_status(ST0_CU1 | ST0_CU2);

		else
@@ -39,8 +39,8 @@ static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action, 
			KSTK_STATUS(current) |= ST0_FR;

		else

			KSTK_STATUS(current) &= ~ST0_FR;

		/* If FPU is enabled, we needn't init or restore fp */

		if(!fpu_enabled) {

		/* If FPU is owned, we needn't init or restore fp */

		if (!fpu_owned) {

			set_thread_flag(TIF_USEDFPU);

			if (!used_math()) {

				_init_fpu();