4 files changed, 108 insertions, 0 deletions
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 25d5c9664e57..6c74b0bedd60 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -3,6 +3,9 @@ lib-y			+= delay.o
 lib-y			+= memcpy.o
 lib-y			+= memset.o
 lib-y			+= memmove.o
+lib-y			+= strcmp.o
+lib-y			+= strlen.o
+lib-y			+= strncmp.o
 lib-$(CONFIG_MMU)	+= uaccess.o
 lib-$(CONFIG_64BIT)	+= tishift.o
 
diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
new file mode 100644
index 000000000000..8babd712b958
--- /dev/null
+++ b/arch/riscv/lib/strcmp.S
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm-generic/export.h>
+
+/* int strcmp(const char *cs, const char *ct) */
+SYM_FUNC_START(strcmp)
+	/*
+	 * Returns
+	 *   a0 - comparison result, value like strcmp
+	 *
+	 * Parameters
+	 *   a0 - string1
+	 *   a1 - string2
+	 *
+	 * Clobbers
+	 *   t0, t1
+	 */
+1:
+	lbu	t0, 0(a0)
+	lbu	t1, 0(a1)
+	addi	a0, a0, 1
+	addi	a1, a1, 1
+	bne	t0, t1, 2f
+	bnez	t0, 1b
+	li	a0, 0
+	ret
+2:
+	/*
+	 * strcmp only needs to return (< 0, 0, > 0) values
+	 * not necessarily -1, 0, +1
+	 */
+	sub	a0, t0, t1
+	ret
+SYM_FUNC_END(strcmp)
diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
new file mode 100644
index 000000000000..0a3b11853efd
--- /dev/null
+++ b/arch/riscv/lib/strlen.S
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm-generic/export.h>
+
+/* int strlen(const char *s) */
+SYM_FUNC_START(strlen)
+	/*
+	 * Returns
+	 *   a0 - string length
+	 *
+	 * Parameters
+	 *   a0 - String to measure
+	 *
+	 * Clobbers:
+	 *   t0, t1
+	 */
+	mv	t1, a0
+1:
+	lbu	t0, 0(t1)
+	beqz	t0, 2f
+	addi	t1, t1, 1
+	j	1b
+2:
+	sub	a0, t1, a0
+	ret
+SYM_FUNC_END(strlen)
diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
new file mode 100644
index 000000000000..1f644d0a93f6
--- /dev/null
+++ b/arch/riscv/lib/strncmp.S
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm-generic/export.h>
+
+/* int strncmp(const char *cs, const char *ct, size_t count) */
+SYM_FUNC_START(strncmp)
+	/*
+	 * Returns
+	 *   a0 - comparison result, value like strncmp
+	 *
+	 * Parameters
+	 *   a0 - string1
+	 *   a1 - string2
+	 *   a2 - number of characters to compare
+	 *
+	 * Clobbers
+	 *   t0, t1, t2
+	 */
+	li	t2, 0
+1:
+	beq	a2, t2, 2f
+	lbu	t0, 0(a0)
+	lbu	t1, 0(a1)
+	addi	a0, a0, 1
+	addi	a1, a1, 1
+	bne	t0, t1, 3f
+	addi	t2, t2, 1
+	bnez	t0, 1b
+2:
+	li	a0, 0
+	ret
+3:
+	/*
+	 * strncmp only needs to return (< 0, 0, > 0) values
+	 * not necessarily -1, 0, +1
+	 */
+	sub	a0, t0, t1
+	ret
+SYM_FUNC_END(strncmp)