diff --git a/include/lib/libc/stdlib.h b/include/lib/libc/stdlib.h
index 3b5e915..a0354fa 100644
--- a/include/lib/libc/stdlib.h
+++ b/include/lib/libc/stdlib.h
@@ -27,4 +27,5 @@
 
 long strtol(const char *nptr, char **endptr, int base);
 unsigned long strtoul(const char *nptr, char **endptr, int base);
+long long strtoll(const char *nptr, char **endptr, int base);
 #endif /* STDLIB_H */
diff --git a/lib/libc/libc.mk b/lib/libc/libc.mk
index 851fadf..85a58bf 100644
--- a/lib/libc/libc.mk
+++ b/lib/libc/libc.mk
@@ -28,6 +28,7 @@
 			strrchr.c			\
 			strtok.c			\
 			strtoul.c			\
+			strtoll.c			\
 			strtol.c)
 
 ifeq (${ARCH},aarch64)
diff --git a/lib/libc/libc_asm.mk b/lib/libc/libc_asm.mk
index e959687..e3f5c67 100644
--- a/lib/libc/libc_asm.mk
+++ b/lib/libc/libc_asm.mk
@@ -27,6 +27,7 @@
 			strrchr.c			\
 			strtok.c			\
 			strtoul.c			\
+			strtoll.c			\
 			strtol.c)
 
 ifeq (${ARCH},aarch64)
diff --git a/lib/libc/strtoll.c b/lib/libc/strtoll.c
new file mode 100644
index 0000000..4e101e8
--- /dev/null
+++ b/lib/libc/strtoll.c
@@ -0,0 +1,134 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Copyright (c) 2011 The FreeBSD Foundation
+ * All rights reserved.
+ * Portions of this software were developed by David Chisnall
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+/*
+ * Convert a string to a long long integer.
+ *
+ * Assumes that the upper and lower case
+ * alphabets and digits are each contiguous.
+ */
+long long strtoll(const char *nptr, char **endptr, int base)
+{
+	const char *s;
+	unsigned long long acc;
+	char c;
+	unsigned long long cutoff;
+	int neg, any, cutlim;
+
+	/*
+	 * Skip white space and pick up leading +/- sign if any.
+	 * If base is 0, allow 0x for hex and 0 for octal, else
+	 * assume decimal; if base is already 16, allow 0x.
+	 */
+	s = nptr;
+	do {
+		c = *s++;
+	} while (isspace((unsigned char)c));
+	if (c == '-') {
+		neg = 1;
+		c = *s++;
+	} else {
+		neg = 0;
+		if (c == '+')
+			c = *s++;
+	}
+	if ((base == 0 || base == 16) &&
+	    c == '0' && (*s == 'x' || *s == 'X') &&
+	    ((s[1] >= '0' && s[1] <= '9') ||
+	    (s[1] >= 'A' && s[1] <= 'F') ||
+	    (s[1] >= 'a' && s[1] <= 'f'))) {
+		c = s[1];
+		s += 2;
+		base = 16;
+	}
+	if (base == 0)
+		base = c == '0' ? 8 : 10;
+	acc = any = 0;
+
+	/*
+	 * Compute the cutoff value between legal numbers and illegal
+	 * numbers.  That is the largest legal value, divided by the
+	 * base.  An input number that is greater than this value, if
+	 * followed by a legal input character, is too big.  One that
+	 * is equal to this value may be valid or not; the limit
+	 * between valid and invalid numbers is then based on the last
+	 * digit.  For instance, if the range for quads is
+	 * [-9223372036854775808..9223372036854775807] and the input base
+	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
+	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
+	 * accumulated a value > 922337203685477580, or equal but the
+	 * next digit is > 7 (or 8), the number is too big, and we will
+	 * return a range error.
+	 *
+	 * Set 'any' if any `digits' consumed; make it negative to indicate
+	 * overflow.
+	 */
+	cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
+	    : LLONG_MAX;
+	cutlim = cutoff % base;
+	cutoff /= base;
+	for ( ; ; c = *s++) {
+		if (c >= '0' && c <= '9')
+			c -= '0';
+		else if (c >= 'A' && c <= 'Z')
+			c -= 'A' - 10;
+		else if (c >= 'a' && c <= 'z')
+			c -= 'a' - 10;
+		else
+			break;
+		if (c >= base)
+			break;
+		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
+			any = -1;
+		else {
+			any = 1;
+			acc *= base;
+			acc += c;
+		}
+	}
+	if (any < 0) {
+		acc = neg ? LLONG_MIN : LLONG_MAX;
+	} else if (neg)
+		acc = -acc;
+	if (endptr != NULL)
+		*endptr = (char *)(any ? s - 1 : nptr);
+	return (acc);
+}