diff --git a/arch/arm/include/asm/semihosting.h b/arch/arm/include/asm/semihosting.h
index e59b44ed6068..835ca7e4b683 100644
--- a/arch/arm/include/asm/semihosting.h
+++ b/arch/arm/include/asm/semihosting.h
@@ -12,6 +12,6 @@
  * code for more information.
  */
 int smh_load(const char *fname, void *memp, int avail, int verbose);
-int smh_len(const char *fname);
+long smh_len(const char *fname);
 
 #endif /* __SEMIHOSTING_H__ */
diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
index 92bbabe158fe..6e1b2d182eca 100644
--- a/arch/arm/lib/semihosting.c
+++ b/arch/arm/lib/semihosting.c
@@ -23,17 +23,17 @@
 #define MODE_READ	0x0
 #define MODE_READBIN	0x1
 
-static int smh_read(int fd, void *memp, int len);
-static int smh_open(const char *fname, char *modestr);
-static int smh_close(int fd);
-static int smh_len_fd(int fd);
+static long smh_read(long fd, void *memp, size_t len);
+static long smh_open(const char *fname, char *modestr);
+static long smh_close(long fd);
+static long smh_len_fd(long fd);
 
 /*
  * Call the handler
  */
-static int smh_trap(unsigned int sysnum, void *addr)
+static long smh_trap(unsigned int sysnum, void *addr)
 {
-	register int result asm("r0");
+	register long result asm("r0");
 #if defined(CONFIG_ARM64)
 	asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
 #else
@@ -51,7 +51,9 @@ static int smh_trap(unsigned int sysnum, void *addr)
  */
 int smh_load(const char *fname, void *memp, int avail, int verbose)
 {
-	int ret, fd, len;
+	long ret;
+	long fd;
+	size_t len;
 
 	ret = -1;
 
@@ -61,21 +63,21 @@ int smh_load(const char *fname, void *memp, int avail, int verbose)
 	/* Open the file */
 	fd = smh_open(fname, "rb");
 	if (fd == -1)
-		return ret;
+		return -1;
 
 	/* Get the file length */
 	ret = smh_len_fd(fd);
 	if (ret == -1) {
 		smh_close(fd);
-		return ret;
+		return -1;
 	}
 
 	/* Check that the file will fit in the supplied buffer */
 	if (ret > avail) {
-		printf("%s: ERROR ret %d, avail %u\n", __func__, ret,
+		printf("%s: ERROR ret %ld, avail %u\n", __func__, ret,
 		       avail);
 		smh_close(fd);
-		return ret;
+		return -1;
 	}
 
 	len = ret;
@@ -87,7 +89,7 @@ int smh_load(const char *fname, void *memp, int avail, int verbose)
 		if (verbose) {
 			printf("\n%s\n", fname);
 			printf("    0x%8p dest\n", memp);
-			printf("    0x%08x size\n", len);
+			printf("    0x%08lx size\n", len);
 			printf("    0x%08x avail\n", avail);
 		}
 	}
@@ -101,54 +103,53 @@ int smh_load(const char *fname, void *memp, int avail, int verbose)
 /*
  * Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure
  */
-static int smh_read(int fd, void *memp, int len)
+static long smh_read(long fd, void *memp, size_t len)
 {
-	int ret;
+	long ret;
 	struct smh_read_s {
-		int fd;
+		long fd;
 		void *memp;
-		int len;
+		size_t len;
 	} read;
 
-	debug("%s: fd %d, memp %p, len %d\n", __func__, fd, memp, len);
+	debug("%s: fd %ld, memp %p, len %lu\n", __func__, fd, memp, len);
 
 	read.fd = fd;
 	read.memp = memp;
 	read.len = len;
 
 	ret = smh_trap(SYSREAD, &read);
-	if (ret == 0) {
-		return 0;
-	} else {
+	if (ret < 0) {
 		/*
 		 * The ARM handler allows for returning partial lengths,
 		 * but in practice this never happens so rather than create
 		 * hard to maintain partial read loops and such, just fail
 		 * with an error message.
 		 */
-		printf("%s: ERROR ret %d, fd %d, len %u memp %p\n",
+		printf("%s: ERROR ret %ld, fd %ld, len %lu memp %p\n",
 		       __func__, ret, fd, len, memp);
+		return -1;
 	}
-	return ret;
+
+	return 0;
 }
 
 /*
  * Open a file on the host. Mode is "r" or "rb" currently. Returns a file
  * descriptor or -1 on error.
  */
-static int smh_open(const char *fname, char *modestr)
+static long smh_open(const char *fname, char *modestr)
 {
-	int ret, fd, mode;
+	long fd;
+	unsigned long mode;
 	struct smh_open_s {
 		const char *fname;
-		unsigned int mode;
-		unsigned int len;
+		unsigned long mode;
+		size_t len;
 	} open;
 
 	debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr);
 
-	ret = -1;
-
 	/* Check the file mode */
 	if (!(strcmp(modestr, "r"))) {
 		mode = MODE_READ;
@@ -157,7 +158,7 @@ static int smh_open(const char *fname, char *modestr)
 	} else {
 		printf("%s: ERROR mode \'%s\' not supported\n", __func__,
 		       modestr);
-		return ret;
+		return -1;
 	}
 
 	open.fname = fname;
@@ -167,7 +168,7 @@ static int smh_open(const char *fname, char *modestr)
 	/* Open the file on the host */
 	fd = smh_trap(SYSOPEN, &open);
 	if (fd == -1)
-		printf("%s: ERROR fd %d for file \'%s\'\n", __func__, fd,
+		printf("%s: ERROR fd %ld for file \'%s\'\n", __func__, fd,
 		       fname);
 
 	return fd;
@@ -176,17 +177,15 @@ static int smh_open(const char *fname, char *modestr)
 /*
  * Close the file using the file descriptor
  */
-static int smh_close(int fd)
+static long smh_close(long fd)
 {
-	int ret;
-	long fdlong;
+	long ret;
 
-	debug("%s: fd %d\n", __func__, fd);
+	debug("%s: fd %ld\n", __func__, fd);
 
-	fdlong = (long)fd;
-	ret = smh_trap(SYSCLOSE, &fdlong);
+	ret = smh_trap(SYSCLOSE, &fd);
 	if (ret == -1)
-		printf("%s: ERROR fd %d\n", __func__, fd);
+		printf("%s: ERROR fd %ld\n", __func__, fd);
 
 	return ret;
 }
@@ -194,17 +193,15 @@ static int smh_close(int fd)
 /*
  * Get the file length from the file descriptor
  */
-static int smh_len_fd(int fd)
+static long smh_len_fd(long fd)
 {
-	int ret;
-	long fdlong;
+	long ret;
 
-	debug("%s: fd %d\n", __func__, fd);
+	debug("%s: fd %ld\n", __func__, fd);
 
-	fdlong = (long)fd;
-	ret = smh_trap(SYSFLEN, &fdlong);
+	ret = smh_trap(SYSFLEN, &fd);
 	if (ret == -1)
-		printf("%s: ERROR ret %d\n", __func__, ret);
+		printf("%s: ERROR ret %ld, fd %ld\n", __func__, ret, fd);
 
 	return ret;
 }
@@ -212,27 +209,31 @@ static int smh_len_fd(int fd)
 /*
  * Get the file length from the filename
  */
-int smh_len(const char *fname)
+long smh_len(const char *fname)
 {
-	int ret, fd, len;
+	long ret;
+	long fd;
+	long len;
 
 	debug("%s: file \'%s\'\n", __func__, fname);
 
 	/* Open the file */
 	fd = smh_open(fname, "rb");
-	if (fd == -1)
+	if (fd < 0)
 		return fd;
 
 	/* Get the file length */
 	len = smh_len_fd(fd);
+	if (len < 0)
+		return len;
 
 	/* Close the file */
 	ret = smh_close(fd);
-	if (ret == -1)
+	if (ret < 0)
 		return ret;
 
-	debug("%s: returning len %d\n", __func__, len);
+	debug("%s: returning len %ld\n", __func__, len);
 
 	/* Return the file length (or -1 error indication) */
-	return len;
+	return (long)len;
 }
