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authorHuacai Chen <chenhuacai@loongson.cn>2023-05-01 12:19:27 +0300
committerHuacai Chen <chenhuacai@loongson.cn>2023-05-01 12:19:27 +0300
commit2b3bd32ea3a22ea2d5e591da4ac2c2b1fb17c0e0 (patch)
tree471e30e5fb3a312649f60e7ff597039a6e8d99d8 /arch
parentc23e7f01cf621290770069d968ca4c8356a50d00 (diff)
downloadlinux-2b3bd32ea3a22ea2d5e591da4ac2c2b1fb17c0e0.tar.xz
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: WANG Xuerui <kernel@xen0n.name> Tested-by: WANG Xuerui <kernel@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch')
-rw-r--r--arch/loongarch/include/asm/fpu.h3
-rw-r--r--arch/loongarch/kernel/Makefile2
-rw-r--r--arch/loongarch/kernel/kfpu.c43
3 files changed, 47 insertions, 1 deletions
diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
index 358b254d9c1d..192f8e35d912 100644
--- a/arch/loongarch/include/asm/fpu.h
+++ b/arch/loongarch/include/asm/fpu.h
@@ -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 *);
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 78d4e3384305..9a72d91cd104 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -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
diff --git a/arch/loongarch/kernel/kfpu.c b/arch/loongarch/kernel/kfpu.c
new file mode 100644
index 000000000000..5c46ae8c6cac
--- /dev/null
+++ b/arch/loongarch/kernel/kfpu.c
@@ -0,0 +1,43 @@
+// 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);