1 files changed, 129 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
new file mode 100644
index 000000000000..358b254d9c1d
--- /dev/null
+++ b/arch/loongarch/include/asm/fpu.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Author: Huacai Chen <chenhuacai@loongson.cn>
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FPU_H
+#define _ASM_FPU_H
+
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/ptrace.h>
+#include <linux/thread_info.h>
+#include <linux/bitops.h>
+
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/current.h>
+#include <asm/loongarch.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+
+struct sigcontext;
+
+extern void _init_fpu(unsigned int);
+extern void _save_fp(struct loongarch_fpu *);
+extern void _restore_fp(struct loongarch_fpu *);
+
+/*
+ * Mask the FCSR Cause bits according to the Enable bits, observing
+ * that Unimplemented is always enabled.
+ */
+static inline unsigned long mask_fcsr_x(unsigned long fcsr)
+{
+	return fcsr & ((fcsr & FPU_CSR_ALL_E) <<
+			(ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E)));
+}
+
+static inline int is_fp_enabled(void)
+{
+	return (csr_read32(LOONGARCH_CSR_EUEN) & CSR_EUEN_FPEN) ?
+		1 : 0;
+}
+
+#define enable_fpu()		set_csr_euen(CSR_EUEN_FPEN)
+
+#define disable_fpu()		clear_csr_euen(CSR_EUEN_FPEN)
+
+#define clear_fpu_owner()	clear_thread_flag(TIF_USEDFPU)
+
+static inline int is_fpu_owner(void)
+{
+	return test_thread_flag(TIF_USEDFPU);
+}
+
+static inline void __own_fpu(void)
+{
+	enable_fpu();
+	set_thread_flag(TIF_USEDFPU);
+	KSTK_EUEN(current) |= CSR_EUEN_FPEN;
+}
+
+static inline void own_fpu_inatomic(int restore)
+{
+	if (cpu_has_fpu && !is_fpu_owner()) {
+		__own_fpu();
+		if (restore)
+			_restore_fp(&current->thread.fpu);
+	}
+}
+
+static inline void own_fpu(int restore)
+{
+	preempt_disable();
+	own_fpu_inatomic(restore);
+	preempt_enable();
+}
+
+static inline void lose_fpu_inatomic(int save, struct task_struct *tsk)
+{
+	if (is_fpu_owner()) {
+		if (save)
+			_save_fp(&tsk->thread.fpu);
+		disable_fpu();
+		clear_tsk_thread_flag(tsk, TIF_USEDFPU);
+	}
+	KSTK_EUEN(tsk) &= ~(CSR_EUEN_FPEN | CSR_EUEN_LSXEN | CSR_EUEN_LASXEN);
+}
+
+static inline void lose_fpu(int save)
+{
+	preempt_disable();
+	lose_fpu_inatomic(save, current);
+	preempt_enable();
+}
+
+static inline void init_fpu(void)
+{
+	unsigned int fcsr = current->thread.fpu.fcsr;
+
+	__own_fpu();
+	_init_fpu(fcsr);
+	set_used_math();
+}
+
+static inline void save_fp(struct task_struct *tsk)
+{
+	if (cpu_has_fpu)
+		_save_fp(&tsk->thread.fpu);
+}
+
+static inline void restore_fp(struct task_struct *tsk)
+{
+	if (cpu_has_fpu)
+		_restore_fp(&tsk->thread.fpu);
+}
+
+static inline union fpureg *get_fpu_regs(struct task_struct *tsk)
+{
+	if (tsk == current) {
+		preempt_disable();
+		if (is_fpu_owner())
+			_save_fp(&current->thread.fpu);
+		preempt_enable();
+	}
+
+	return tsk->thread.fpu.fpr;
+}
+
+#endif /* _ASM_FPU_H */