diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
index bb06a1b7eef0c0914b1dc7013f7774a960088e7b..6482ed877f974b787e711e046a92ec69617c6e8b 100644
--- a/arch/nds32/Kconfig.cpu
+++ b/arch/nds32/Kconfig.cpu
@@ -28,6 +28,19 @@ config LAZY_FPU
 
 	  For nomal case, say Y.
 
+config SUPPORT_DENORMAL_ARITHMETIC
+	bool "Denormal arithmetic support"
+	depends on FPU
+	default n
+	help
+	  Say Y here to enable arithmetic of denormalized number. Enabling
+	  this feature can enhance the precision for tininess number.
+	  However, performance loss in float pointe calculations is
+	  possibly significant due to additional FPU exception.
+
+	  If the calculated tolerance for tininess number is not critical,
+	  say N to prevent performance loss.
+
 config HWZOL
 	bool "hardware zero overhead loop support"
 	depends on CPU_D10 || CPU_D15
diff --git a/arch/nds32/include/asm/elf.h b/arch/nds32/include/asm/elf.h
index f5f9cf7e054401431f89b72af891c5a44b20baba..95f3ea253e4c34e269c9b5d3ba1ccbc0a98d1f20 100644
--- a/arch/nds32/include/asm/elf.h
+++ b/arch/nds32/include/asm/elf.h
@@ -9,6 +9,7 @@
  */
 
 #include <asm/ptrace.h>
+#include <asm/fpu.h>
 
 typedef unsigned long elf_greg_t;
 typedef unsigned long elf_freg_t[3];
@@ -159,8 +160,18 @@ struct elf32_hdr;
 
 #endif
 
+
+#if IS_ENABLED(CONFIG_FPU)
+#define FPU_AUX_ENT	NEW_AUX_ENT(AT_FPUCW, FPCSR_INIT)
+#else
+#define FPU_AUX_ENT	NEW_AUX_ENT(AT_IGNORE, 0)
+#endif
+
 #define ARCH_DLINFO						\
 do {								\
+	/* Optional FPU initialization */			\
+	FPU_AUX_ENT;						\
+								\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR,				\
 		    (elf_addr_t)current->mm->context.vdso);	\
 } while (0)
diff --git a/arch/nds32/include/asm/fpu.h b/arch/nds32/include/asm/fpu.h
index 9b1107b58e23ec74729f29caf00a09a51ac3773f..019f1bcfc5ee17e4f5390ebaa7806ec90395e9f2 100644
--- a/arch/nds32/include/asm/fpu.h
+++ b/arch/nds32/include/asm/fpu.h
@@ -28,7 +28,18 @@ extern int do_fpuemu(struct pt_regs *regs, struct fpu_struct *fpu);
 #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;
 
diff --git a/arch/nds32/include/asm/syscalls.h b/arch/nds32/include/asm/syscalls.h
index 78778ecff60c44efd0cb2f663699d22bc2dc5b42..da32101b455d764a125649f3791cc3f4332db15c 100644
--- a/arch/nds32/include/asm/syscalls.h
+++ b/arch/nds32/include/asm/syscalls.h
@@ -7,6 +7,7 @@
 asmlinkage long sys_cacheflush(unsigned long addr, unsigned long len, unsigned int op);
 asmlinkage long sys_fadvise64_64_wrapper(int fd, int advice, loff_t offset, loff_t len);
 asmlinkage long sys_rt_sigreturn_wrapper(void);
+asmlinkage long sys_udftrap(int option);
 
 #include <asm-generic/syscalls.h>
 
diff --git a/arch/nds32/include/uapi/asm/auxvec.h b/arch/nds32/include/uapi/asm/auxvec.h
index 56043ce4972f052ea9da1c7c52b19a8232abaf68..2d3213f5e59583162babb3b6ad05eafa116828ad 100644
--- a/arch/nds32/include/uapi/asm/auxvec.h
+++ b/arch/nds32/include/uapi/asm/auxvec.h
@@ -4,6 +4,13 @@
 #ifndef __ASM_AUXVEC_H
 #define __ASM_AUXVEC_H
 
+/*
+ * This entry gives some information about the FPU initialization
+ * performed by the kernel.
+ */
+#define AT_FPUCW	18	/* Used FPU control word.  */
+
+
 /* VDSO location */
 #define AT_SYSINFO_EHDR	33
 
diff --git a/arch/nds32/include/uapi/asm/sigcontext.h b/arch/nds32/include/uapi/asm/sigcontext.h
index 1257a78e3ae19ffd35fb2b80e6eeb0e65571dfe7..58afc416473e578817a23073693dfd87a61251c1 100644
--- a/arch/nds32/include/uapi/asm/sigcontext.h
+++ b/arch/nds32/include/uapi/asm/sigcontext.h
@@ -12,6 +12,15 @@
 struct fpu_struct {
 	unsigned long long fd_regs[32];
 	unsigned long fpcsr;
+	/*
+	 * UDF_trap is used to recognize whether underflow trap is enabled
+	 * or not. When UDF_trap == 1, this process will be traped and then
+	 * get a SIGFPE signal when encountering an underflow exception.
+	 * UDF_trap is only modified through setfputrap syscall. Therefore,
+	 * UDF_trap needn't be saved or loaded to context in each context
+	 * switch.
+	 */
+	unsigned long UDF_trap;
 };
 
 struct zol_struct {
diff --git a/arch/nds32/include/uapi/asm/udftrap.h b/arch/nds32/include/uapi/asm/udftrap.h
new file mode 100644
index 0000000000000000000000000000000000000000..433f79d679c0acedcbf4dfd6e356b3fc2047998d
--- /dev/null
+++ b/arch/nds32/include/uapi/asm/udftrap.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2005-2018 Andes Technology Corporation */
+#ifndef	_ASM_SETFPUTRAP
+#define	_ASM_SETFPUTRAP
+
+/*
+ * Options for setfputrap system call
+ */
+#define	DISABLE_UDFTRAP	0	/* disable underflow exception trap */
+#define	ENABLE_UDFTRAP	1	/* enable undeflos exception trap */
+#define	GET_UDFTRAP	2	/* only get undeflos exception trap status */
+
+#endif /* _ASM_CACHECTL */
diff --git a/arch/nds32/include/uapi/asm/unistd.h b/arch/nds32/include/uapi/asm/unistd.h
index 603e826e04491a5167156961829e9f4ed9ff6e6d..c2c3a3e340836ff3bee656fb31ca9578ce904f08 100644
--- a/arch/nds32/include/uapi/asm/unistd.h
+++ b/arch/nds32/include/uapi/asm/unistd.h
@@ -9,4 +9,6 @@
 
 /* Additional NDS32 specific syscalls. */
 #define __NR_cacheflush		(__NR_arch_specific_syscall)
+#define __NR_udftrap		(__NR_arch_specific_syscall + 1)
 __SYSCALL(__NR_cacheflush, sys_cacheflush)
+__SYSCALL(__NR_udftrap, sys_udftrap)
diff --git a/arch/nds32/kernel/fpu.c b/arch/nds32/kernel/fpu.c
index 2942df6f93e66a00684c96ee8231730e86b5eff9..fddd40c7a16f9880d2082cb71aa3431ac4192ac5 100644
--- a/arch/nds32/kernel/fpu.c
+++ b/arch/nds32/kernel/fpu.c
@@ -12,7 +12,10 @@
 
 const struct fpu_struct init_fpuregs = {
 	.fd_regs = {[0 ... 31] = sNAN64},
-	.fpcsr = FPCSR_INIT
+	.fpcsr = FPCSR_INIT,
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+	.UDF_trap = 0
+#endif
 };
 
 void save_fpu(struct task_struct *tsk)
@@ -174,6 +177,9 @@ inline void do_fpu_context_switch(struct pt_regs *regs)
 	} else {
 		/* First time FPU user.  */
 		load_fpu(&init_fpuregs);
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+		current->thread.fpu.UDF_trap = init_fpuregs.UDF_trap;
+#endif
 		set_used_math();
 	}
 
@@ -183,10 +189,12 @@ inline void fill_sigfpe_signo(unsigned int fpcsr, int *signo)
 {
 	if (fpcsr & FPCSR_mskOVFT)
 		*signo = FPE_FLTOVF;
-	else if (fpcsr & FPCSR_mskIVOT)
-		*signo = FPE_FLTINV;
+#ifndef CONFIG_SUPPORT_DENORMAL_ARITHMETIC
 	else if (fpcsr & FPCSR_mskUDFT)
 		*signo = FPE_FLTUND;
+#endif
+	else if (fpcsr & FPCSR_mskIVOT)
+		*signo = FPE_FLTINV;
 	else if (fpcsr & FPCSR_mskDBZT)
 		*signo = FPE_FLTDIV;
 	else if (fpcsr & FPCSR_mskIEXT)
@@ -197,11 +205,20 @@ inline void handle_fpu_exception(struct pt_regs *regs)
 {
 	unsigned int fpcsr;
 	int si_code = 0, si_signo = SIGFPE;
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+	unsigned long redo_except = FPCSR_mskDNIT|FPCSR_mskUDFT;
+#else
+	unsigned long redo_except = FPCSR_mskDNIT;
+#endif
 
 	lose_fpu();
 	fpcsr = current->thread.fpu.fpcsr;
 
-	if (fpcsr & FPCSR_mskDNIT) {
+	if (fpcsr & redo_except) {
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+		if (fpcsr & FPCSR_mskUDFT)
+			current->thread.fpu.fpcsr &= ~FPCSR_mskIEX;
+#endif
 		si_signo = do_fpuemu(regs, &current->thread.fpu);
 		fpcsr = current->thread.fpu.fpcsr;
 		if (!si_signo)
diff --git a/arch/nds32/kernel/sys_nds32.c b/arch/nds32/kernel/sys_nds32.c
index 9de93ab4c52b7244960ec83163f92d9253df67bb..0835277636ce31f1a3ba75dbbcd33a7d0f0d31eb 100644
--- a/arch/nds32/kernel/sys_nds32.c
+++ b/arch/nds32/kernel/sys_nds32.c
@@ -6,6 +6,8 @@
 
 #include <asm/cachectl.h>
 #include <asm/proc-fns.h>
+#include <asm/udftrap.h>
+#include <asm/fpu.h>
 
 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	       unsigned long, prot, unsigned long, flags,
@@ -48,3 +50,33 @@ SYSCALL_DEFINE3(cacheflush, unsigned int, start, unsigned int, end, int, cache)
 
 	return 0;
 }
+
+SYSCALL_DEFINE1(udftrap, int, option)
+{
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+	int old_udftrap;
+
+	if (!used_math()) {
+		load_fpu(&init_fpuregs);
+		current->thread.fpu.UDF_trap = init_fpuregs.UDF_trap;
+		set_used_math();
+	}
+
+	old_udftrap = current->thread.fpu.UDF_trap;
+	switch (option) {
+	case DISABLE_UDFTRAP:
+		current->thread.fpu.UDF_trap = 0;
+		break;
+	case ENABLE_UDFTRAP:
+		current->thread.fpu.UDF_trap = FPCSR_mskUDFE;
+		break;
+	case GET_UDFTRAP:
+		break;
+	default:
+		return -EINVAL;
+	}
+	return old_udftrap;
+#else
+	return -ENOTSUPP;
+#endif
+}
diff --git a/arch/nds32/math-emu/fpuemu.c b/arch/nds32/math-emu/fpuemu.c
index 2a01333d6e5fef75d500e02d8e2c619bbd031d30..75cf1643fa78e6ede16924169cdddb49187e05ce 100644
--- a/arch/nds32/math-emu/fpuemu.c
+++ b/arch/nds32/math-emu/fpuemu.c
@@ -304,7 +304,12 @@ static int fpu_emu(struct fpu_struct *fpu_reg, unsigned long insn)
 	/*
 	 * If an exception is required, generate a tidy SIGFPE exception.
 	 */
+#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC)
+	if (((fpu_reg->fpcsr << 5) & fpu_reg->fpcsr & FPCSR_mskALLE_NO_UDFE) ||
+	    ((fpu_reg->fpcsr & FPCSR_mskUDF) && (fpu_reg->UDF_trap)))
+#else
 	if ((fpu_reg->fpcsr << 5) & fpu_reg->fpcsr & FPCSR_mskALLE)
+#endif
 		return SIGFPE;
 	return 0;
 }