7 files changed, 134 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
index 909049366555..a96b1fea24fe 100644
--- a/arch/riscv/include/asm/string.h
+++ b/arch/riscv/include/asm/string.h
@@ -18,6 +18,16 @@ extern asmlinkage void *__memcpy(void *, const void *, size_t);
 #define __HAVE_ARCH_MEMMOVE
 extern asmlinkage void *memmove(void *, const void *, size_t);
 extern asmlinkage void *__memmove(void *, const void *, size_t);
+
+#define __HAVE_ARCH_STRCMP
+extern asmlinkage int strcmp(const char *cs, const char *ct);
+
+#define __HAVE_ARCH_STRLEN
+extern asmlinkage __kernel_size_t strlen(const char *);
+
+#define __HAVE_ARCH_STRNCMP
+extern asmlinkage int strncmp(const char *cs, const char *ct, size_t count);
+
 /* For those files which don't want to check by kasan. */
 #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
 #define memcpy(dst, src, len) __memcpy(dst, src, len)
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index 5ab1c7e1a6ed..a72879b4249a 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/arch/riscv/kernel/riscv_ksyms.c
@@ -12,6 +12,9 @@
 EXPORT_SYMBOL(memset);
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
+EXPORT_SYMBOL(strcmp);
+EXPORT_SYMBOL(strlen);
+EXPORT_SYMBOL(strncmp);
 EXPORT_SYMBOL(__memset);
 EXPORT_SYMBOL(__memcpy);
 EXPORT_SYMBOL(__memmove);
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)
diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index dd58e1d99397..d16bf715a586 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -2,6 +2,7 @@
 OBJECT_FILES_NON_STANDARD := y
 
 purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o
+purgatory-y += strcmp.o strlen.o strncmp.o
 
 targets += $(purgatory-y)
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
@@ -18,6 +19,15 @@ $(obj)/memcpy.o: $(srctree)/arch/riscv/lib/memcpy.S FORCE
 $(obj)/memset.o: $(srctree)/arch/riscv/lib/memset.S FORCE
 	$(call if_changed_rule,as_o_S)
 
+$(obj)/strcmp.o: $(srctree)/arch/riscv/lib/strcmp.S FORCE
+	$(call if_changed_rule,as_o_S)
+
+$(obj)/strlen.o: $(srctree)/arch/riscv/lib/strlen.S FORCE
+	$(call if_changed_rule,as_o_S)
+
+$(obj)/strncmp.o: $(srctree)/arch/riscv/lib/strncmp.S FORCE
+	$(call if_changed_rule,as_o_S)
+
 $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
@@ -77,6 +87,9 @@ CFLAGS_ctype.o			+= $(PURGATORY_CFLAGS)
 AFLAGS_REMOVE_entry.o		+= -Wa,-gdwarf-2
 AFLAGS_REMOVE_memcpy.o		+= -Wa,-gdwarf-2
 AFLAGS_REMOVE_memset.o		+= -Wa,-gdwarf-2
+AFLAGS_REMOVE_strcmp.o		+= -Wa,-gdwarf-2
+AFLAGS_REMOVE_strlen.o		+= -Wa,-gdwarf-2
+AFLAGS_REMOVE_strncmp.o		+= -Wa,-gdwarf-2
 
 $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
 		$(call if_changed,ld)