4 files changed, 141 insertions, 0 deletions
diff --git a/arch/nds32/include/asm/bitfield.h b/arch/nds32/include/asm/bitfield.h
index 19b2841219ad..c1619730192a 100644
--- a/arch/nds32/include/asm/bitfield.h
+++ b/arch/nds32/include/asm/bitfield.h
@@ -251,6 +251,11 @@
 #define ITYPE_mskSTYPE		( 0xF  << ITYPE_offSTYPE )
 #define ITYPE_mskCPID		( 0x3  << ITYPE_offCPID )
 
+/* Additional definitions of ITYPE register for FPU */
+#define FPU_DISABLE_EXCEPTION	(0x1  << ITYPE_offSTYPE)
+#define FPU_EXCEPTION		(0x2  << ITYPE_offSTYPE)
+#define FPU_CPID		0	/* FPU Co-Processor ID is 0 */
+
 #define NDS32_VECTOR_mskNONEXCEPTION	0x78
 #define NDS32_VECTOR_offEXCEPTION	8
 #define NDS32_VECTOR_offINTERRUPT	9
@@ -926,6 +931,7 @@
 #define FPCSR_mskDNIT           ( 0x1  << FPCSR_offDNIT )
 #define FPCSR_mskRIT		( 0x1  << FPCSR_offRIT )
 #define FPCSR_mskALL		(FPCSR_mskIVO | FPCSR_mskDBZ | FPCSR_mskOVF | FPCSR_mskUDF | FPCSR_mskIEX)
+#define FPCSR_mskALLE_NO_UDFE	(FPCSR_mskIVOE | FPCSR_mskDBZE | FPCSR_mskOVFE | FPCSR_mskIEXE)
 #define FPCSR_mskALLE		(FPCSR_mskIVOE | FPCSR_mskDBZE | FPCSR_mskOVFE | FPCSR_mskUDFE | FPCSR_mskIEXE)
 #define FPCSR_mskALLT           (FPCSR_mskIVOT | FPCSR_mskDBZT | FPCSR_mskOVFT | FPCSR_mskUDFT | FPCSR_mskIEXT |FPCSR_mskDNIT | FPCSR_mskRIT)
 
@@ -946,6 +952,15 @@
 #define FPCFG_mskIMVER		( 0x1F  << FPCFG_offIMVER )
 #define FPCFG_mskAVER		( 0x1F  << FPCFG_offAVER )
 
+/* 8 Single precision or 4 double precision registers are available */
+#define SP8_DP4_reg		0
+/* 16 Single precision or 8 double precision registers are available */
+#define SP16_DP8_reg		1
+/* 32 Single precision or 16 double precision registers are available */
+#define SP32_DP16_reg		2
+/* 32 Single precision or 32 double precision registers are available */
+#define SP32_DP32_reg		3
+
 /******************************************************************************
  * fucpr: FUCOP_CTL (FPU and Coprocessor Enable Control Register)
  *****************************************************************************/
diff --git a/arch/nds32/include/asm/fpu.h b/arch/nds32/include/asm/fpu.h
new file mode 100644
index 000000000000..f7a7f6b2ea8f
--- /dev/null
+++ b/arch/nds32/include/asm/fpu.h
@@ -0,0 +1,114 @@
+/* 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);
+
+#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
+
+#define FPCSR_INIT  0x0UL
+
+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 */
diff --git a/arch/nds32/include/asm/processor.h b/arch/nds32/include/asm/processor.h
index c2660f566bac..72024f8bc129 100644
--- a/arch/nds32/include/asm/processor.h
+++ b/arch/nds32/include/asm/processor.h
@@ -35,6 +35,8 @@ struct thread_struct {
 	unsigned long address;
 	unsigned long trap_no;
 	unsigned long error_code;
+
+	struct fpu_struct fpu;
 };
 
 #define INIT_THREAD  {	}
@@ -72,6 +74,11 @@ struct task_struct;
 
 /* Free all resources held by a thread. */
 #define release_thread(thread) do { } while(0)
+#if IS_ENABLED(CONFIG_FPU)
+#if !IS_ENABLED(CONFIG_UNLAZU_FPU)
+extern struct task_struct *last_task_used_math;
+#endif
+#endif
 
 /* Prepare to copy thread state - unlazy all lazy status */
 #define prepare_to_copy(tsk)	do { } while (0)
diff --git a/arch/nds32/include/uapi/asm/sigcontext.h b/arch/nds32/include/uapi/asm/sigcontext.h
index 00567b237b0c..1257a78e3ae1 100644
--- a/arch/nds32/include/uapi/asm/sigcontext.h
+++ b/arch/nds32/include/uapi/asm/sigcontext.h
@@ -9,6 +9,10 @@
  * before the signal handler was invoked.  Note: only add new entries
  * to the end of the structure.
  */
+struct fpu_struct {
+	unsigned long long fd_regs[32];
+	unsigned long fpcsr;
+};
 
 struct zol_struct {
 	unsigned long nds32_lc;	/* $LC */
@@ -54,6 +58,7 @@ struct sigcontext {
 	unsigned long fault_address;
 	unsigned long used_math_flag;
 	/* FPU Registers */
+	struct fpu_struct fpu;
 	struct zol_struct zol;
 };