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-rw-r--r--arch/nds32/include/asm/fpu.h126
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/nds32/include/asm/fpu.h b/arch/nds32/include/asm/fpu.h
new file mode 100644
index 000000000000..019f1bcfc5ee
--- /dev/null
+++ b/arch/nds32/include/asm/fpu.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2005-2018 Andes Technology Corporation */
+
+#ifndef __ASM_NDS32_FPU_H
+#define __ASM_NDS32_FPU_H
+
+#if IS_ENABLED(CONFIG_FPU)
+#ifndef __ASSEMBLY__
+#include <linux/sched/task_stack.h>
+#include <linux/preempt.h>
+#include <asm/ptrace.h>
+
+extern bool has_fpu;
+
+extern void save_fpu(struct task_struct *__tsk);
+extern void load_fpu(const struct fpu_struct *fpregs);
+extern bool do_fpu_exception(unsigned int subtype, struct pt_regs *regs);
+extern int do_fpuemu(struct pt_regs *regs, struct fpu_struct *fpu);
+
+#define test_tsk_fpu(regs) (regs->fucop_ctl & FUCOP_CTL_mskCP0EN)
+
+/*
+ * Initially load the FPU with signalling NANS. This bit pattern
+ * has the property that no matter whether considered as single or as
+ * double precision, it still represents a signalling NAN.
+ */
+
+#define sNAN64 0xFFFFFFFFFFFFFFFFULL
+#define sNAN32 0xFFFFFFFFUL
+
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+/*
+ * Denormalized number is unsupported by nds32 FPU. Hence the operation
+ * is treated as underflow cases when the final result is a denormalized
+ * number. To enhance precision, underflow exception trap should be
+ * enabled by default and kerenl will re-execute it by fpu emulator
+ * when getting underflow exception.
+ */
+#define FPCSR_INIT FPCSR_mskUDFE
+#else
+#define FPCSR_INIT 0x0UL
+#endif
+
+extern const struct fpu_struct init_fpuregs;
+
+static inline void disable_ptreg_fpu(struct pt_regs *regs)
+{
+ regs->fucop_ctl &= ~FUCOP_CTL_mskCP0EN;
+}
+
+static inline void enable_ptreg_fpu(struct pt_regs *regs)
+{
+ regs->fucop_ctl |= FUCOP_CTL_mskCP0EN;
+}
+
+static inline void enable_fpu(void)
+{
+ unsigned long fucop_ctl;
+
+ fucop_ctl = __nds32__mfsr(NDS32_SR_FUCOP_CTL) | FUCOP_CTL_mskCP0EN;
+ __nds32__mtsr(fucop_ctl, NDS32_SR_FUCOP_CTL);
+ __nds32__isb();
+}
+
+static inline void disable_fpu(void)
+{
+ unsigned long fucop_ctl;
+
+ fucop_ctl = __nds32__mfsr(NDS32_SR_FUCOP_CTL) & ~FUCOP_CTL_mskCP0EN;
+ __nds32__mtsr(fucop_ctl, NDS32_SR_FUCOP_CTL);
+ __nds32__isb();
+}
+
+static inline void lose_fpu(void)
+{
+ preempt_disable();
+#if IS_ENABLED(CONFIG_LAZY_FPU)
+ if (last_task_used_math == current) {
+ last_task_used_math = NULL;
+#else
+ if (test_tsk_fpu(task_pt_regs(current))) {
+#endif
+ save_fpu(current);
+ }
+ disable_ptreg_fpu(task_pt_regs(current));
+ preempt_enable();
+}
+
+static inline void own_fpu(void)
+{
+ preempt_disable();
+#if IS_ENABLED(CONFIG_LAZY_FPU)
+ if (last_task_used_math != current) {
+ if (last_task_used_math != NULL)
+ save_fpu(last_task_used_math);
+ load_fpu(&current->thread.fpu);
+ last_task_used_math = current;
+ }
+#else
+ if (!test_tsk_fpu(task_pt_regs(current))) {
+ load_fpu(&current->thread.fpu);
+ }
+#endif
+ enable_ptreg_fpu(task_pt_regs(current));
+ preempt_enable();
+}
+
+#if !IS_ENABLED(CONFIG_LAZY_FPU)
+static inline void unlazy_fpu(struct task_struct *tsk)
+{
+ preempt_disable();
+ if (test_tsk_fpu(task_pt_regs(tsk)))
+ save_fpu(tsk);
+ preempt_enable();
+}
+#endif /* !CONFIG_LAZY_FPU */
+static inline void clear_fpu(struct pt_regs *regs)
+{
+ preempt_disable();
+ if (test_tsk_fpu(regs))
+ disable_ptreg_fpu(regs);
+ preempt_enable();
+}
+#endif /* CONFIG_FPU */
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_NDS32_FPU_H */