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2b3bd32ea3
Provide kernel_fpu_begin()/kernel_fpu_end() to allow the kernel itself to use fpu. They can be used by some other kernel components, e.g., the AMDGPU graphic driver for DCN. Reported-by: WANG Xuerui <kernel@xen0n.name> Tested-by: WANG Xuerui <kernel@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
44 lines
778 B
C
44 lines
778 B
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2023 Loongson Technology Corporation Limited
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*/
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#include <linux/cpu.h>
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#include <linux/init.h>
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#include <asm/fpu.h>
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#include <asm/smp.h>
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static DEFINE_PER_CPU(bool, in_kernel_fpu);
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void kernel_fpu_begin(void)
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{
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preempt_disable();
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WARN_ON(this_cpu_read(in_kernel_fpu));
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this_cpu_write(in_kernel_fpu, true);
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if (!is_fpu_owner())
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enable_fpu();
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else
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_save_fp(¤t->thread.fpu);
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write_fcsr(LOONGARCH_FCSR0, 0);
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}
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EXPORT_SYMBOL_GPL(kernel_fpu_begin);
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void kernel_fpu_end(void)
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{
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WARN_ON(!this_cpu_read(in_kernel_fpu));
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if (!is_fpu_owner())
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disable_fpu();
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else
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_restore_fp(¤t->thread.fpu);
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this_cpu_write(in_kernel_fpu, false);
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preempt_enable();
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}
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EXPORT_SYMBOL_GPL(kernel_fpu_end);
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