From 11df93a1dd1bc281e07f2315565f2f3236911bd0 Mon Sep 17 00:00:00 2001
From: Djordje Todorovic <djordje.todorovic@htecgroup.com>
Date: Wed, 14 Aug 2024 13:54:06 +0200
Subject: [PATCH 1/4] configure: Add --with-endian option

---
 Makefile.in  |  6 +++++-
 configure    | 16 ++++++++++++++++
 configure.ac |  4 ++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Makefile.in b/Makefile.in
index e6fc8ec8224..2bfbf698f37 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -84,7 +84,11 @@ ifneq ($(XLEN),32)
 	XLEN := 64
 endif
 
-make_tuple = riscv$(1)-unknown-$(2)
+ifeq (@endian@,big)
+ENDIAN_POSTFIX := be
+endif
+
+make_tuple = riscv$(1)$(ENDIAN_POSTFIX)-unknown-$(2)
 LINUX_TUPLE  ?= $(call make_tuple,$(XLEN),linux-gnu)
 NEWLIB_TUPLE ?= $(call make_tuple,$(XLEN),elf)
 MUSL_TUPLE ?= $(call make_tuple,$(XLEN),linux-musl)
diff --git a/configure b/configure
index 2fc589e7db6..ecc38fe896b 100755
--- a/configure
+++ b/configure
@@ -641,6 +641,7 @@ configure_host
 target_cxxflags
 target_cflags
 cmodel
+endian
 gcc_checking
 musl_multilib_names
 newlib_multilib_names
@@ -730,6 +731,7 @@ with_multilib_generator
 with_extra_multilib_test
 enable_gcc_checking
 with_cmodel
+with_endian
 with_target_cflags
 with_target_cxxflags
 with_host
@@ -1426,6 +1428,7 @@ Optional Packages:
                           --with-extra-multilib-test="rv64gcv-lp64;rv64gcv_zba-lp64"
   --with-cmodel           Select the code model to use when building libc and
                           libgcc [--with-cmodel=medlow]
+  --with-endian           Select the target endianess [--with-endian=little]
   --with-target-cflags    Add extra target flags for C for library code
   --with-target-cxxflags  Add extra target flags for C++ for library code
   --with-host=x86_64-w64-mingw32
@@ -4080,6 +4083,19 @@ WITH_SIM=$with_sim
 WITH_LANGUAGES=$with_languages
 
 
+# Check whether --with-endian was given.
+if test "${with_endian+set}" = set; then :
+  withval=$with_endian;
+fi
+
+if test "x$with_endian" != x; then :
+  endian=$with_endian
+
+else
+  endian=little
+
+fi
+
 # Check whether --enable-multilib was given.
 if test ${enable_multilib+y}
 then :
diff --git a/configure.ac b/configure.ac
index 80ca038bbe0..bae4c57ffae 100644
--- a/configure.ac
+++ b/configure.ac
@@ -188,6 +188,10 @@ AS_IF([test "x$with_cmodel" != xno],
 	[AC_SUBST(cmodel, -mcmodel=$with_cmodel)],
 	[AC_SUBST(cmodel, -mcmodel=medlow)])
 
+AS_IF([test "x$with_endian" != x],
+	[AC_SUBST(endian, endian=$with_endian)],
+	[AC_SUBST(endian, endian=little)])
+
 AC_ARG_WITH(target_cflags,
 	[AS_HELP_STRING([--with-target-cflags],
 		[Add extra target flags for C for library code])],

From c9d6ddce5118cf12f2343a3b68a4ad098207e7ee Mon Sep 17 00:00:00 2001
From: Djordje Todorovic <djordje.todorovic@htecgroup.com>
Date: Wed, 14 Aug 2024 13:56:48 +0200
Subject: [PATCH 2/4] linux-headers: Ensure proper endianess

---
 linux-headers/include/asm/byteorder.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/linux-headers/include/asm/byteorder.h b/linux-headers/include/asm/byteorder.h
index 03ac550720f..44552373908 100644
--- a/linux-headers/include/asm/byteorder.h
+++ b/linux-headers/include/asm/byteorder.h
@@ -7,6 +7,10 @@
 #ifndef _ASM_RISCV_BYTEORDER_H
 #define _ASM_RISCV_BYTEORDER_H
 
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 #include <linux/byteorder/little_endian.h>
+#else
+#include <linux/byteorder/big_endian.h>
+#endif
 
 #endif /* _ASM_RISCV_BYTEORDER_H */

From 6355cfd32766c4f7790b241bff650e675a322ea9 Mon Sep 17 00:00:00 2001
From: Djordje Todorovic <djordje.todorovic@htecgroup.com>
Date: Wed, 14 Aug 2024 13:57:44 +0200
Subject: [PATCH 3/4] README: Add BE instructions

---
 README.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/README.md b/README.md
index 8dc1910937a..125f2aa2bc6 100644
--- a/README.md
+++ b/README.md
@@ -111,6 +111,15 @@ This option only takes effect for the GNU toolchain.
 The toolchain has an option `--enable-strip` to control strip of host binaries,
 strip is disabled by default.
 
+### Big Endian configuration
+
+To build either cross-compiler with support for big endian targets, run the following command:
+
+```
+./configure --prefix=/opt/riscv --with-endian=big
+make (target)
+```
+
 ### Troubleshooting Build Problems
 
 Builds work best if installing into an empty directory.  If you build a

From e01382e9b0f3f3004c89ac1fce62db327eb90901 Mon Sep 17 00:00:00 2001
From: Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
Date: Thu, 4 Dec 2025 16:01:12 +0100
Subject: [PATCH 4/4] configure: Fix glibc multilib build on BE platforms

---
 configure | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index ecc38fe896b..b76b701a629 100755
--- a/configure
+++ b/configure
@@ -4154,7 +4154,12 @@ fi
 
 if test "x$enable_multilib" = xyes
 then :
-  glibc_multilib_names="rv32imac-ilp32 rv32gc-ilp32d rv64imac-lp64 rv64gc-lp64d rv64gcv-lp64d"
+  glibc_multilib_names="rv32imac-ilp32 rv32gc-ilp32d rv64imac-lp64 rv64gc-lp64d"
+  # Vector extension is currently not supported on Big-endian systems. 
+  if test "x$endian" = xlittle
+  then :
+       glibc_multilib_names+=" rv64gcv-lp64d"
+  fi
 
 else $as_nop
   glibc_multilib_names="$with_arch-$with_abi"