Commit 2b3bd32e authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Provide kernel fpu functions 



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: default avatarWANG Xuerui <kernel@xen0n.name>
Tested-by: default avatarWANG Xuerui <kernel@xen0n.name>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent c23e7f01

arch/loongarch/include/asm/fpu.h

+3 −0
Original line number Diff line number Diff line
@@ -21,6 +21,9 @@ 


struct sigcontext;



extern void kernel_fpu_begin(void);

extern void kernel_fpu_end(void);



extern void _init_fpu(unsigned int);

extern void _save_fp(struct loongarch_fpu *);

extern void _restore_fp(struct loongarch_fpu *);

arch/loongarch/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ obj-y += head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \ 
obj-$(CONFIG_ACPI)		+= acpi.o

obj-$(CONFIG_EFI) 		+= efi.o



obj-$(CONFIG_CPU_HAS_FPU)	+= fpu.o

obj-$(CONFIG_CPU_HAS_FPU)	+= fpu.o kfpu.o



obj-$(CONFIG_ARCH_STRICT_ALIGN)	+= unaligned.o

arch/loongarch/kernel/kfpu.c

0 → 100644
+43 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2023 Loongson Technology Corporation Limited

 */



#include <linux/cpu.h>

#include <linux/init.h>

#include <asm/fpu.h>

#include <asm/smp.h>



static DEFINE_PER_CPU(bool, in_kernel_fpu);



void kernel_fpu_begin(void)

{

	preempt_disable();



	WARN_ON(this_cpu_read(in_kernel_fpu));



	this_cpu_write(in_kernel_fpu, true);



	if (!is_fpu_owner())

		enable_fpu();

	else

		_save_fp(&current->thread.fpu);



	write_fcsr(LOONGARCH_FCSR0, 0);

}

EXPORT_SYMBOL_GPL(kernel_fpu_begin);



void kernel_fpu_end(void)

{

	WARN_ON(!this_cpu_read(in_kernel_fpu));



	if (!is_fpu_owner())

		disable_fpu();

	else

		_restore_fp(&current->thread.fpu);



	this_cpu_write(in_kernel_fpu, false);



	preempt_enable();

}

EXPORT_SYMBOL_GPL(kernel_fpu_end);