From 6e7a3d52201a3b624265a3d843d85cd6e025c7b8 Mon Sep 17 00:00:00 2001
From: Abhishek Akkabathula <a.akkabathul@samsung.com>
Date: Mon, 19 Feb 2024 17:45:33 +0530
Subject: [PATCH] apps/platform, os/binfmt: add exceptions support in loadable

Add support for cpp exceptions in loadable for RTL8730E and
RTL8721CSM.

Signed-off-by: Abhishek Akkabathula <a.akkabathul@samsung.com>
---
 apps/platform/gnu/Make.defs                   |  4 ++
 apps/platform/gnu/gnu_unwind_find_exidx.c     | 50 +++++++++++++++++++
 build/configs/rtl8721csm/Make.defs            | 12 ++++-
 .../configs/rtl8721csm/cpp_loadable/defconfig | 45 +++++++++++++----
 build/configs/rtl8730e/Make.defs              | 12 ++++-
 .../configs/rtl8730e/loadable_apps/defconfig  | 12 ++++-
 lib/libc/machine/arm/armv7-a/arch_elf.c       | 13 ++++-
 lib/libc/machine/arm/armv7-m/arch_elf.c       |  2 +-
 loadable_apps/loadable.mk                     | 18 +++++--
 os/Makefile.unix                              |  2 +-
 os/arch/arm/src/armv7-a/Kconfig               |  6 +++
 os/binfmt/libelf/Kconfig                      |  2 +-
 os/binfmt/libelf/libelf_load.c                |  6 +--
 os/include/tinyara/elf.h                      | 20 --------
 os/include/wctype.h                           |  8 +++
 os/userspace/userspace_apps.ld                | 12 +++++
 16 files changed, 175 insertions(+), 49 deletions(-)
 create mode 100644 apps/platform/gnu/gnu_unwind_find_exidx.c

diff --git a/apps/platform/gnu/Make.defs b/apps/platform/gnu/Make.defs
index b9b4ba1c5f..ef7980715e 100644
--- a/apps/platform/gnu/Make.defs
+++ b/apps/platform/gnu/Make.defs
@@ -56,6 +56,10 @@ ifeq ($(CONFIG_HAVE_CXXINITIALIZE),y)
 CSRCS += gnu_cxxinitialize.c
 endif
 
+ifeq ($(CONFIG_LIBCXX_EXCEPTION),y)
+CSRCS += gnu_unwind_find_exidx.c
+endif
+
 # Add the gnu/ sub-directory to the build
 
 VPATH += :gnu
diff --git a/apps/platform/gnu/gnu_unwind_find_exidx.c b/apps/platform/gnu/gnu_unwind_find_exidx.c
new file mode 100644
index 0000000000..14b237611a
--- /dev/null
+++ b/apps/platform/gnu/gnu_unwind_find_exidx.c
@@ -0,0 +1,50 @@
+/****************************************************************************
+ *
+ * Copyright 2024 Samsung Electronics All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <unwind.h>
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+extern void *__exidx_start;
+extern void *__exidx_end;
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name:  __gnu_Unwind_Find_exidx
+ *
+ * Description:
+ *    This function is called (if exists) by the gcc generated unwind
+ *    run-time in order to retrieve an alternative .ARM.exidx Exception
+ *    index section.
+ *
+ ****************************************************************************/
+
+volatile _Unwind_Ptr __gnu_Unwind_Find_exidx(_Unwind_Ptr return_address, int *nrecp)
+{
+	*nrecp = &__exidx_end - &__exidx_start;
+	return (_Unwind_Ptr)&__exidx_start;
+}
diff --git a/build/configs/rtl8721csm/Make.defs b/build/configs/rtl8721csm/Make.defs
index 487dd9c9d5..3122cd6102 100644
--- a/build/configs/rtl8721csm/Make.defs
+++ b/build/configs/rtl8721csm/Make.defs
@@ -170,7 +170,7 @@ else ifeq ($(CONFIG_CXX_VERSION_14),y)
 else
   CXXFLAGS += -std=c++11
 endif
-  CXXFLAGS += -pedantic -D_DEBUG -D_LIBCPP_BUILD_STATIC -ffunction-sections -fdata-sections -D__GLIBCXX__
+  CXXFLAGS += -pedantic -D_DEBUG -D_LIBCPP_BUILD_STATIC -ffunction-sections -fdata-sections -D__GLIBCXX__ -DCONFIG_WCHAR_BUILTIN
 endif
 
 ifeq ($(CONFIG_EXTERNAL_TFMICRO),y)
@@ -249,7 +249,8 @@ ifeq ($(CONFIG_APP_BINARY_SEPARATION),y)
 CELFFLAGS = $(CFLAGS) -mlong-calls # --target1-abs
 CXXELFFLAGS = $(CXXFLAGS) -mlong-calls # --target1-abs
 
-LDELFFLAGS = -r -e main
+LDELFFLAGS = -r
+LDELFENTRY = -e main
 
 ifeq ($(WINTOOL),y)
 	LDELFFLAGS += -T "${shell cygpath -w $(TOPDIR)/userspace/userspace_apps.ld}"
@@ -258,6 +259,13 @@ else
 endif
 endif
 
+ifeq ($(CONFIG_LIBCXX_EXCEPTION),y)
+#this symbol __gnu_Unwind_Find_exidx should be present in all the cpp binaries (apps, common)
+#as it is used to decide which exception table. Also, --force-group-allocation flag is required
+#to not generate additional sections with group flag, as we dont support loading such sections.
+LDELFFLAGS += --require-defined __gnu_Unwind_Find_exidx --force-group-allocation
+endif
+
 LDFLAGS += --gc-sections
 LDFLAGS += --defsym=CONFIG_IDLETHREAD_STACKSIZE=$(CONFIG_IDLETHREAD_STACKSIZE)
 
diff --git a/build/configs/rtl8721csm/cpp_loadable/defconfig b/build/configs/rtl8721csm/cpp_loadable/defconfig
index 98c0a1c92a..0d37205143 100644
--- a/build/configs/rtl8721csm/cpp_loadable/defconfig
+++ b/build/configs/rtl8721csm/cpp_loadable/defconfig
@@ -65,13 +65,20 @@ CONFIG_ARCH="arm"
 # CONFIG_ARCH_CHIP_LM is not set
 # CONFIG_ARCH_CHIP_S5J is not set
 # CONFIG_ARCH_CHIP_BCM4390X is not set
+# CONFIG_ARCH_CHIP_IMX6 is not set
 # CONFIG_ARCH_CHIP_STM32 is not set
 # CONFIG_ARCH_CHIP_IMXRT is not set
 # CONFIG_ARCH_CHIP_STM32L4 is not set
 CONFIG_ARCH_CHIP_AMEBAD=y
 # CONFIG_ARCH_CHIP_STM32H745 is not set
 # CONFIG_ARCH_CHIP_AMEBALITE is not set
+# CONFIG_ARCH_CHIP_AMEBASMART is not set
 CONFIG_ARCH_CHIP="amebad"
+# CONFIG_ARM_THUMB is not set
+# CONFIG_ARM_HAVE_DPFPU32 is not set
+# CONFIG_ARM_HAVE_NEON is not set
+# CONFIG_ARM_FPU_ABI_SOFT is not set
+# CONFIG_ARM_HAVE_MPCORE is not set
 
 #
 # ARM Options
@@ -81,10 +88,13 @@ CONFIG_ARCH_CHIP="amebad"
 # CONFIG_ARCH_CORTEXM7 is not set
 CONFIG_ARCH_CORTEXM33=y
 # CONFIG_ARCH_CORTEXM55 is not set
+# CONFIG_ARCH_CORTEXA9 is not set
 # CONFIG_ARCH_CORTEXR4 is not set
+# CONFIG_ARCH_CORTEXA32 is not set
 # CONFIG_ARCH_ARMV7M_FAMILY is not set
 CONFIG_ARCH_ARMV8M_FAMILY=y
 # CONFIG_ARCH_ARMV7R_FAMILY is not set
+# CONFIG_ARCH_ARMV7A_FAMILY is not set
 CONFIG_ARCH_FAMILY="armv8-m"
 CONFIG_ARCH_HAVE_CMNVECTOR=y
 CONFIG_ARM_CMNVECTOR=y
@@ -124,7 +134,7 @@ CONFIG_ARMV8M_DCACHE=y
 # CONFIG_ARMV8M_TOOLCHAIN_CODESOURCERYL is not set
 CONFIG_ARMV8M_TOOLCHAIN_GNU_EABIL=y
 # CONFIG_ARMV8M_TOOLCHAIN_CLANGL is not set
-# CONFIG_ARMV8M_TARGET2_PREL is not set
+CONFIG_ARMV8M_TARGET2_PREL=y
 # CONFIG_ARMV8M_HAVE_STACKCHECK is not set
 # CONFIG_ARMV8M_ITMSYSLOG is not set
 
@@ -146,11 +156,7 @@ CONFIG_RTL8721D_UART2=y
 CONFIG_AMEBAD_I2CTIMEOSEC=0
 CONFIG_AMEBAD_I2CTIMEOMS=500
 CONFIG_AMEBAD_I2CTIMEOTICKS=500
-CONFIG_RTL8721D_SPI=y
-CONFIG_SPI1_MASTER=y
-# CONFIG_CONFIG_SPI_CS is not set
-CONFIG_CONFIG_SPI_EXCHANGE=y
-CONFIG_CONFIG_SPI_CMDDATA=y
+# CONFIG_AMEBAD_SPI is not set
 
 #
 # Realtek RTL8721D WIFI Support
@@ -168,6 +174,11 @@ CONFIG_AMEBAD_WIFI=y
 CONFIG_AMEBAD_TRUSTZONE=y
 # CONFIG_AMEBAD_RDP is not set
 
+#
+# Realtek RTL8721D CMSIS_NN Support
+#
+# CONFIG_AMEBAD_CMSIS_NN is not set
+
 #
 # Architecture Options
 #
@@ -179,6 +190,8 @@ CONFIG_ARCH_HAVE_IRQPRIO=y
 # CONFIG_ARCH_HAVE_COHERENT_DCACHE is not set
 # CONFIG_ARCH_HAVE_ADDRENV is not set
 # CONFIG_ARCH_NEED_ADDRENV_MAPPING is not set
+# CONFIG_ARCH_HAVE_MULTICPU is not set
+# CONFIG_ARCH_HAVE_TESTSET is not set
 CONFIG_ARCH_HAVE_VFORK=y
 # CONFIG_ARCH_HAVE_MMU is not set
 CONFIG_ARCH_HAVE_MPU=y
@@ -186,9 +199,12 @@ CONFIG_ARCH_HAVE_MPU=y
 # CONFIG_ARCH_HAVE_EXTCLK is not set
 # CONFIG_ARCH_HAVE_POWEROFF is not set
 CONFIG_ARCH_HAVE_RESET=y
+# CONFIG_ARCH_HAVE_FETCHADD is not set
 CONFIG_ARCH_USE_MPU=y
 CONFIG_ARCH_IRQPRIO=y
+# CONFIG_ARCH_TASKDUMP is not set
 CONFIG_ARCH_STACKDUMP=y
+CONFIG_ARCH_STACKDUMP_MAX_LENGTH=0
 # CONFIG_ENDIAN_BIG is not set
 # CONFIG_ARCH_IDLE_CUSTOM is not set
 # CONFIG_ARCH_HAVE_RAMFUNCS is not set
@@ -225,6 +241,8 @@ CONFIG_BOOT_RUNFROMFLASH=y
 #
 # Boot Memory Configuration
 #
+CONFIG_RAM_START=0x0
+CONFIG_RAM_SIZE=0
 CONFIG_RAM_KREGIONx_START="0x10005000,0x02000000,0x02100000"
 CONFIG_RAM_KREGIONx_SIZE="466944,1048576,2859008,"
 CONFIG_RAM_KREGIONx_HEAP_INDEX="0,0,1,"
@@ -285,6 +303,7 @@ CONFIG_FLASH_PART_NAME="bl1,bl2,reserved,ss,system_data,kernel,kernel,common,com
 # CONFIG_ARCH_BOARD_HAVE_SECOND_FLASH is not set
 CONFIG_AUTOMOUNT=y
 CONFIG_AUTOMOUNT_USERFS=y
+# CONFIG_BOARD_USBDEV_SERIALSTR is not set
 
 #
 # SE Selection
@@ -339,7 +358,10 @@ CONFIG_PREALLOC_TIMERS=8
 #
 # Tasks and Scheduling
 #
+# CONFIG_SPINLOCK is not set
 CONFIG_INIT_ENTRYPOINT=y
+# CONFIG_IRQCOUNT is not set
+# CONFIG_SCHED_RESUMESCHEDULER is not set
 CONFIG_RR_INTERVAL=10
 CONFIG_TASK_NAME_SIZE=31
 CONFIG_MAX_TASKS=32
@@ -977,9 +999,9 @@ CONFIG_MTD_SMART_JOURNALING=y
 # CONFIG_ARASTORAGE is not set
 
 #
-# Light Weight AI Framework
+# AI Framework
 #
-# CONFIG_LW_AIFW is not set
+# CONFIG_AIFW is not set
 
 #
 # AraUI Framework
@@ -1181,7 +1203,7 @@ CONFIG_CXX_VERSION_11=y
 # LLVM C++ Library (libcxx)
 #
 CONFIG_LIBCXX=y
-# CONFIG_LIBCXX_EXCEPTION is not set
+CONFIG_LIBCXX_EXCEPTION=y
 CONFIG_LIBCXX_IOSTREAM_BUFSIZE=32
 CONFIG_LIBCXX_HAVE_LIBSUPCXX=y
 
@@ -1225,6 +1247,7 @@ CONFIG_ELF_ALIGN_LOG2=2
 CONFIG_ELF_STACKSIZE=2048
 CONFIG_ELF_BUFFERSIZE=32
 CONFIG_ELF_BUFFERINCR=32
+CONFIG_ELF_EXIDX_SECTNAME=".ARM.exidx"
 CONFIG_ELF_EXCLUDE_SYMBOLS=y
 CONFIG_ELF_CACHE_READ=y
 CONFIG_ELF_CACHE_BLOCK_SIZE=2048
@@ -1268,6 +1291,7 @@ CONFIG_BUILTIN_APPS=y
 #
 # Board Specific Demos
 #
+# CONFIG_EXAMPLES_AMEBA_MIPI is not set
 # CONFIG_EXAMPLES_SSTORAGE is not set
 # CONFIG_EXAMPLES_SECURE_WORLD is not set
 # CONFIG_EXAMPLES_WIFICSI is not set
@@ -1301,8 +1325,8 @@ CONFIG_EXAMPLES_HELLOXX=y
 #
 # CONFIG_EXAMPLES_LIBTUV is not set
 # CONFIG_EXAMPLES_LWNL_SAMPLE is not set
-# CONFIG_EXAMPLES_MEMORY_FRAGMENTATION_TEST is not set
 CONFIG_EXAMPLES_MEM_PROTECT_TEST=y
+# CONFIG_EXAMPLES_MEMORY_FRAGMENTATION_TEST is not set
 # CONFIG_EXAMPLES_NETTEST is not set
 
 #
@@ -1462,7 +1486,6 @@ CONFIG_EXAMPLES_WIFIMANAGER_AP_LIST_ITEMS_COUNT=10
 # Platform-specific Support
 #
 # CONFIG_PLATFORM_CONFIGDATA is not set
-# CONFIG_HAVE_CXXINITIALIZE is not set
 
 #
 # Shell
diff --git a/build/configs/rtl8730e/Make.defs b/build/configs/rtl8730e/Make.defs
index ab6f4823d4..06bfc6f301 100755
--- a/build/configs/rtl8730e/Make.defs
+++ b/build/configs/rtl8730e/Make.defs
@@ -168,7 +168,7 @@ else ifeq ($(CONFIG_CXX_VERSION_14),y)
 else
   CXXFLAGS += -std=c++11
 endif
-  CXXFLAGS += -pedantic -D_DEBUG -D_LIBCPP_BUILD_STATIC -ffunction-sections -fdata-sections -D__GLIBCXX__
+  CXXFLAGS += -pedantic -D_DEBUG -D_LIBCPP_BUILD_STATIC -ffunction-sections -fdata-sections -D__GLIBCXX__  -DCONFIG_WCHAR_BUILTIN
 endif
 
 ifeq ($(CONFIG_LIBCXX_EXCEPTION),y)
@@ -241,7 +241,8 @@ ifeq ($(CONFIG_APP_BINARY_SEPARATION),y)
 CELFFLAGS = $(CFLAGS) -mlong-calls # --target1-abs
 CXXELFFLAGS = $(CXXFLAGS) -mlong-calls # --target1-abs
 
-LDELFFLAGS = -r -e main
+LDELFFLAGS = -r 
+LDELFENTRY = -e main
 
 ifeq ($(WINTOOL),y)
 	LDELFFLAGS += -T "${shell cygpath -w $(TOPDIR)/userspace/userspace_apps.ld}"
@@ -250,6 +251,13 @@ else
 endif
 endif
 
+ifeq ($(CONFIG_LIBCXX_EXCEPTION),y)
+#this symbol __gnu_Unwind_Find_exidx should be present in all the cpp binaries (apps, common)
+#as it is used to decide which exception table. Also, --force-group-allocation flag is required
+#to not generate additional sections with group flag, as we dont support loading such sections.
+LDELFFLAGS += --require-defined __gnu_Unwind_Find_exidx --force-group-allocation
+endif
+
 LDFLAGS += --gc-sections
 LDFLAGS += --defsym=CONFIG_IDLETHREAD_STACKSIZE=$(CONFIG_IDLETHREAD_STACKSIZE)
 
diff --git a/build/configs/rtl8730e/loadable_apps/defconfig b/build/configs/rtl8730e/loadable_apps/defconfig
index 40bc5c174b..b72886bd6e 100644
--- a/build/configs/rtl8730e/loadable_apps/defconfig
+++ b/build/configs/rtl8730e/loadable_apps/defconfig
@@ -140,6 +140,7 @@ CONFIG_ARMV7A_WAYSIZE_16KB=y
 # CONFIG_ARMV7A_TOOLCHAIN_BUILDROOT is not set
 CONFIG_ARMV7A_TOOLCHAIN_GNU_EABI=y
 # CONFIG_ARMV7A_TOOLCHAIN_GNU_OABI is not set
+# CONFIG_ARMV7A_TARGET2_PREL is not set
 # CONFIG_ARMV7A_DECODEFIQ is not set
 
 #
@@ -161,6 +162,7 @@ CONFIG_AMEBASMART_SPI=y
 CONFIG_AMEBASMART_SPI0=y
 CONFIG_AMEBASMART_SPI1=y
 CONFIG_AMEBASMART_SPI_EXCHANGE=y
+# CONFIG_SPI_CS is not set
 # CONFIG_AMEBASMART_MIPI is not set
 # CONFIG_AMEBASMART_I2C is not set
 # CONFIG_AMEBASMART_I2S is not set
@@ -216,6 +218,7 @@ CONFIG_ARCH_STACKDUMP=y
 CONFIG_ARCH_STACKDUMP_MAX_LENGTH=0
 # CONFIG_ENDIAN_BIG is not set
 # CONFIG_ARCH_IDLE_CUSTOM is not set
+# CONFIG_ARCH_CUSTOM_PMINIT is not set
 # CONFIG_ARCH_HAVE_RAMFUNCS is not set
 # CONFIG_ARCH_HAVE_RAMVECTORS is not set
 # CONFIG_SUPPRESS_INTERRUPTS is not set
@@ -968,6 +971,7 @@ CONFIG_FS_AUTOMOUNT_PROCFS=y
 # CONFIG_FS_PROCFS_EXCLUDE_MTD is not set
 # CONFIG_FS_PROCFS_EXCLUDE_PARTITIONS is not set
 # CONFIG_FS_PROCFS_EXCLUDE_SMARTFS is not set
+# CONFIG_FS_PROCFS_EXCLUDE_POWER is not set
 # CONFIG_FS_ROMFS is not set
 # CONFIG_FS_TMPFS is not set
 
@@ -1082,7 +1086,7 @@ CONFIG_PM_DEVNAME_LEN=32
 CONFIG_PM_SLICEMS=100
 CONFIG_PM_NDOMAINS=1
 CONFIG_PM_MEMORY=2
-# CONFIG_PM_DVFS is not set
+CONFIG_PM_DVFS=y
 CONFIG_PM_COEFN=1
 CONFIG_PM_COEF1=1
 CONFIG_PM_COEF2=1
@@ -1123,6 +1127,7 @@ CONFIG_DEBUG_FS_ERROR=y
 CONFIG_DEBUG_BLE=y
 CONFIG_DEBUG_BLE_ERROR=y
 CONFIG_DEBUG_PM=y
+# CONFIG_DEBUG_PM_ERROR is not set
 # CONFIG_DEBUG_SCHED is not set
 # CONFIG_DEBUG_SYSCALL is not set
 # CONFIG_DEBUG_TASH is not set
@@ -1260,7 +1265,7 @@ CONFIG_CXX_NEWLONG=y
 # LLVM C++ Library (libcxx)
 #
 CONFIG_LIBCXX=y
-# CONFIG_LIBCXX_EXCEPTION is not set
+CONFIG_LIBCXX_EXCEPTION=y
 CONFIG_LIBCXX_IOSTREAM_BUFSIZE=32
 CONFIG_LIBCXX_HAVE_LIBSUPCXX=y
 
@@ -1319,6 +1324,7 @@ CONFIG_ELF_ALIGN_LOG2=2
 CONFIG_ELF_STACKSIZE=8192
 CONFIG_ELF_BUFFERSIZE=32
 CONFIG_ELF_BUFFERINCR=32
+CONFIG_ELF_EXIDX_SECTNAME=".ARM.exidx"
 CONFIG_ELF_EXCLUDE_SYMBOLS=y
 CONFIG_ELF_CACHE_READ=y
 CONFIG_ELF_CACHE_BLOCK_SIZE=2048
@@ -1387,6 +1393,7 @@ CONFIG_EXAMPLES_HELLO=y
 # CONFIG_EXAMPLES_IOTJS_STARTUP is not set
 # CONFIG_EXAMPLES_KERNEL_SAMPLE is not set
 # CONFIG_EXAMPLES_KERNEL_UPDATE is not set
+# CONFIG_EXAMPLES_LCD is not set
 
 #
 # Libcoap
@@ -1407,6 +1414,7 @@ CONFIG_EXAMPLES_HELLO=y
 # CONFIG_EXAMPLES_TLS_BENCHMARK is not set
 # CONFIG_EXAMPLES_TLS_HANDSHAKE is not set
 # CONFIG_EXAMPLES_TLS_SECLINK is not set
+# CONFIG_EXAMPLES_POWER is not set
 
 #
 # Protocol Buffer
diff --git a/lib/libc/machine/arm/armv7-a/arch_elf.c b/lib/libc/machine/arm/armv7-a/arch_elf.c
index e072e42bdc..dcaf0115ac 100644
--- a/lib/libc/machine/arm/armv7-a/arch_elf.c
+++ b/lib/libc/machine/arm/armv7-a/arch_elf.c
@@ -352,6 +352,17 @@ int up_relocate(const Elf32_Rel *rel, const Elf32_Sym *sym, uintptr_t addr)
 		}
 		break;
 
+#if defined(CONFIG_ARMV7A_TARGET2_PREL)
+	case R_ARM_TARGET2:		/* TARGET2 is a platform-specific relocation: gcc-arm-none-eabi
+								 * performs a self relocation */
+	{
+		binfo("Performing TARGET2 link at addr=%08lx [%08lx] to sym=%p st_value=%08lx\n", (long)addr, (long)(*(uint32_t *)addr), sym, (long)sym->st_value);
+
+		*(uint32_t *)addr += sym->st_value - addr;
+	}
+	break;
+#endif
+
 	case R_ARM_THM_CALL:
 	case R_ARM_THM_JUMP24:
 		{
@@ -483,7 +494,7 @@ int up_relocate(const Elf32_Rel *rel, const Elf32_Sym *sym, uintptr_t addr)
 #endif /* CONFIG_ARM_THUMB */
 
 	default:
-		berr("ERROR: Unsupported relocation: %\n",
+		berr("ERROR: Unsupported relocation: %d\n",
 			ELF32_R_TYPE(rel->r_info));
 		return -EINVAL;
 	}
diff --git a/lib/libc/machine/arm/armv7-m/arch_elf.c b/lib/libc/machine/arm/armv7-m/arch_elf.c
index c006ac1ce1..d70c710229 100644
--- a/lib/libc/machine/arm/armv7-m/arch_elf.c
+++ b/lib/libc/machine/arm/armv7-m/arch_elf.c
@@ -193,7 +193,7 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym, uintptr_t ad
 	}
 	break;
 
-#ifdef CONFIG_ARMV7M_TARGET2_PREL
+#if defined(CONFIG_ARMV7M_TARGET2_PREL) || defined(CONFIG_ARMV8M_TARGET2_PREL)
 	case R_ARM_TARGET2:		/* TARGET2 is a platform-specific relocation: gcc-arm-none-eabi
 								 * performs a self relocation */
 	{
diff --git a/loadable_apps/loadable.mk b/loadable_apps/loadable.mk
index ccd25eefa1..e3172a5013 100644
--- a/loadable_apps/loadable.mk
+++ b/loadable_apps/loadable.mk
@@ -35,7 +35,14 @@ APPDEFINE = ${shell $(TOPDIR)/tools/define.sh "$(CC)" __APP_BUILD__}
 
 SRCS += $(USERSPACE).c
 
+ifeq ($(CONFIG_LIBCXX_EXCEPTION),y)
+ifeq ($(CONFIG_SUPPORT_COMMON_BINARY),y)
+SRCS += $(TOPDIR)/../apps/platform/gnu/gnu_unwind_find_exidx.c
+endif
+endif
+
 OBJS = $(SRCS:.c=$(OBJEXT))
+CPPOBJS = $(patsubst %.cpp,%$(OBJEXT),$(filter %.cpp,$(CXXSRCS)))
 
 prebuild:
 	$(call DELFILE, $(USERSPACE)$(OBJEXT))
@@ -47,13 +54,16 @@ $(OBJS): %$(OBJEXT): %.c
 	@echo "CC: $<"
 	$(Q) $(CC) $(APPDEFINE) -c $(CELFFLAGS) $< -o $@
 
-$(BIN): $(OBJS)
+$(CPPOBJS): %$(OBJEXT): %.cpp
+	$(call COMPILEXX, $<, $@)
+
+$(BIN): $(OBJS) $(CPPOBJS)
 	@echo "LD: $<"
 ifeq ($(CONFIG_SUPPORT_COMMON_BINARY),y)
-	$(Q) $(LD) $(LDELFFLAGS) -o $@ $(ARCHCRT0OBJ) $^ --start-group $(LIBGCC) --end-group
-	$(Q) $(NM) -u $(BIN) | awk -F"U " '{print "--require-defined "$$2}' >> $(USER_BIN_DIR)/lib_symbols.txt
+	$(Q) $(LD) $(LDELFENTRY) $(LDELFFLAGS) -o $@ $(ARCHCRT0OBJ) $^ --start-group $(LIBGCC) $(LIBSUPXX) --end-group
+	$(Q) $(NM) -u $(BIN) | awk -F"[Uw] " '{print "--require-defined "$$2}' >> $(USER_BIN_DIR)/lib_symbols.txt
 else
-	$(Q) $(LD) $(LDELFFLAGS) $(LDLIBPATH) -o $@ $(ARCHCRT0OBJ) $^ --start-group $(LDLIBS) $(LIBSUPXX) --end-group
+	$(Q) $(LD) $(LDELFENTRY) $(LDELFFLAGS) $(LDLIBPATH) -o $@ $(ARCHCRT0OBJ) $^ --start-group $(LIBSUPXX) $(LDLIBS) --end-group
 endif
 
 clean:
diff --git a/os/Makefile.unix b/os/Makefile.unix
index 755505411b..affc689009 100644
--- a/os/Makefile.unix
+++ b/os/Makefile.unix
@@ -450,7 +450,7 @@ pass1: pass1deps
 ifeq ($(CONFIG_BUILD_2PASS),y)
 	$(Q) $(MAKE) -C $(LOADABLE_APPDIR) TOPDIR="$(TOPDIR)" LOADABLEDIR="${LOADABLE_APPDIR}" LIBRARIES_DIR="$(LIBRARIES_DIR)" USERLIBS="$(USERLIBS)" all KERNEL=n
 ifeq ($(CONFIG_SUPPORT_COMMON_BINARY),y)
-	$(Q) $(LD) -r -o $(OUTBIN_DIR)/$(CONFIG_COMMON_BINARY_NAME) -T $(TOPDIR)/userspace/userspace_apps.ld -L $(LIBRARIES_DIR) --start-group $(USERLIBS) $(LIBGCC) $(LIBSUPXX) --end-group $$(cat $(OUTBIN_DIR)/lib_symbols.txt)
+	$(Q) $(LD) $(LDELFFLAGS) -o $(OUTBIN_DIR)/$(CONFIG_COMMON_BINARY_NAME) -L $(LIBRARIES_DIR) --start-group $(USERLIBS) $(LIBGCC) $(LIBSUPXX) --end-group $$(cat $(OUTBIN_DIR)/lib_symbols.txt)
 endif
 endif
 
diff --git a/os/arch/arm/src/armv7-a/Kconfig b/os/arch/arm/src/armv7-a/Kconfig
index 40eedb3887..8ddf567a03 100644
--- a/os/arch/arm/src/armv7-a/Kconfig
+++ b/os/arch/arm/src/armv7-a/Kconfig
@@ -153,6 +153,12 @@ config ARMV7A_TOOLCHAIN_GNU_OABI
 
 endchoice # Toolchain Selection
 
+config ARMV7A_TARGET2_PREL
+	bool "R_ARM_TARGET2 is PC relative"
+	depends on ELF
+	---help---
+		Perform a PC relative relocation for relocation type R_ARM_TARGET2
+
 config ARMV7A_OABI_TOOLCHAIN
 	bool "OABI (vs EABI)"
 	default n
diff --git a/os/binfmt/libelf/Kconfig b/os/binfmt/libelf/Kconfig
index fac9304f60..329c016e98 100644
--- a/os/binfmt/libelf/Kconfig
+++ b/os/binfmt/libelf/Kconfig
@@ -42,7 +42,7 @@ config ELF_DUMPBUFFER
 config ELF_EXIDX_SECTNAME
 	string "ELF Section Name for Exception Index"
 	default ".ARM.exidx"
-	depends on CXX_EXCEPTION
+	depends on LIBCXX_EXCEPTION
 	---help---
 		Set the name string for the exception index section on the ELF modules to
 		be loaded by the ELF binary loader.
diff --git a/os/binfmt/libelf/libelf_load.c b/os/binfmt/libelf/libelf_load.c
index b989aff4e4..eb926d11c8 100644
--- a/os/binfmt/libelf/libelf_load.c
+++ b/os/binfmt/libelf/libelf_load.c
@@ -272,7 +272,7 @@ static inline int elf_loadfile(FAR struct elf_loadinfo_s *loadinfo)
 
 int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 {
-#ifdef CONFIG_CXX_EXCEPTION
+#ifdef CONFIG_LIBCXX_EXCEPTION
 	int exidx;
 #endif
 	int ret;
@@ -324,12 +324,10 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 	}
 #endif
 
-#ifdef CONFIG_CXX_EXCEPTION
+#ifdef CONFIG_LIBCXX_EXCEPTION
 	exidx = elf_findsection(loadinfo, CONFIG_ELF_EXIDX_SECTNAME);
 	if (exidx < 0) {
 		binfo("elf_findsection: Exception Index section not found: %d\n", exidx);
-	} else {
-		up_init_exidx(loadinfo->shdr[exidx].sh_addr, loadinfo->shdr[exidx].sh_size);
 	}
 #endif
 
diff --git a/os/include/tinyara/elf.h b/os/include/tinyara/elf.h
index bf9c0346f7..32a54dc134 100644
--- a/os/include/tinyara/elf.h
+++ b/os/include/tinyara/elf.h
@@ -110,24 +110,4 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym, uintptr_t ad
 int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym, uintptr_t addr);
 #endif
 
-/****************************************************************************
- * Name: up_init_exidx
- *
- * Description:
- *   Initialize the exception index section.
- *
- * Input Parameters:
- *   address - The exception index section address.
- *   size    - The exception index section size.
- *
- * Returned Value:
- *   Zero (OK) if the initialization was successful. Otherwise, a negated errno
- *   value indicating the cause of the failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_CXX_EXCEPTION
-int up_init_exidx(Elf32_Addr address, Elf32_Word size);
-#endif
-
 #endif							/* __INCLUDE_TINYARA_ELF_H */
diff --git a/os/include/wctype.h b/os/include/wctype.h
index ab4ab4a336..a8b06e14c4 100644
--- a/os/include/wctype.h
+++ b/os/include/wctype.h
@@ -92,6 +92,11 @@
  * character mappings.
  */
 
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#endif
+
 typedef int wctrans_t;
 
 /****************************************************************************
@@ -124,4 +129,7 @@ wint_t towupper(wint_t);
 wctrans_t wctrans(FAR const char *);
 wctype_t wctype(FAR const char *);
 
+#if defined(__cplusplus)
+}
+#endif
 #endif							/* INCLUDE_WTYPE_H */
diff --git a/os/userspace/userspace_apps.ld b/os/userspace/userspace_apps.ld
index 5c76b05a8c..efa9949fce 100644
--- a/os/userspace/userspace_apps.ld
+++ b/os/userspace/userspace_apps.ld
@@ -128,6 +128,18 @@ SECTIONS
       _edtors = . ;
     }
 
+  .ARM.extab :
+    {
+      *(.ARM.extab*)
+    }
+
+  .ARM.exidx :
+    {
+      __exidx_start = . ;
+      *(.ARM.exidx*)
+      __exidx_end = . ;
+    }
+
   .bss :
     {
       _sbss = . ;