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: Huacai 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: Ralf Baechle <ralf@linux-mips.org>
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@ -22,13 +22,13 @@
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static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
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void *data)
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{
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int fpu_enabled;
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int fpu_owned;
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int fr = !test_thread_flag(TIF_32BIT_FPREGS);
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switch (action) {
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case CU2_EXCEPTION:
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preempt_disable();
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fpu_enabled = read_c0_status() & ST0_CU1;
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fpu_owned = __is_fpu_owner();
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if (!fr)
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set_c0_status(ST0_CU1 | ST0_CU2);
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else
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@ -39,8 +39,8 @@ static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
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KSTK_STATUS(current) |= ST0_FR;
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else
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KSTK_STATUS(current) &= ~ST0_FR;
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/* If FPU is enabled, we needn't init or restore fp */
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if(!fpu_enabled) {
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/* If FPU is owned, we needn't init or restore fp */
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if (!fpu_owned) {
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set_thread_flag(TIF_USEDFPU);
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if (!used_math()) {
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_init_fpu();
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