[Buildroot] [PATCH] boot/arm-trusted-firmware: fix the RPATH of fiptool

[Louis Chauvet]

The arm-trusted-firmware package builds a host tool called "fiptool",
which is used during the build process of arm-trusted-firmware
itself. This tool links against the OpenSSL host library, and
therefore needs to be built with the correct RPATH pointing to
$HOST_DIR/lib.

This is why commit a957d9a90ade4194dffe3eb2fc0136bc5d077c28
("boot/arm-trusted-firmware: build fiptool separately with dependency
o n host-openssl") added the ARM_TRUSTED_FIRMWARE_BUILD_FIPTOOL
variable, which builds the fiptool tool first, with the right
variables set, before invoking the full build of TF-A. This ensured
that fiptool was built with the correct RPATH.

However, more recent versions of TF-A have modified their Makefile
machinery, and fiptool is being rebuilt even if it was built
before. Unfortunately, this rebuild is no longer done with the right
flags, so we end up with a fiptool binary that no longer has the right
RPATH, and fiptool fails to find the OpenSSL libraries from
$HOST_DIR/lib.

In order to fix this, we take a different approach: we do not build
fiptool separately first, but we inject the necessary flags through
the HOSTCC variable. Indeed, there's no HOST_LDFLAGS or HOST_LDLIBS
variable or similar that would allow us to pass the -Wl,-rpath flag
that is needed. Shoe-horning this flag into HOSTCC gets the job done,
and actually simplifies our arm-trusted-firmware.mk.

Signed-off-by: Louis Chauvet <louis.chauvet at bootlin.com>
Co-authored-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 .../arm-trusted-firmware/arm-trusted-firmware.mk | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/boot/arm-trusted-firmware/arm-trusted-firmware.mk b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
index 049beed36a91..bed873a1821c 100644
--- a/boot/arm-trusted-firmware/arm-trusted-firmware.mk
+++ b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
@@ -63,7 +63,8 @@ ARM_TRUSTED_FIRMWARE_MAKE_OPTS += \
 	BUILD_STRING=$(ARM_TRUSTED_FIRMWARE_VERSION) \
 	$(call qstrip,$(BR2_TARGET_ARM_TRUSTED_FIRMWARE_ADDITIONAL_VARIABLES)) \
 	PLAT=$(ARM_TRUSTED_FIRMWARE_PLATFORM) \
-	TARGET_BOARD=$(ARM_TRUSTED_FIRMWARE_TARGET_BOARD)
+	TARGET_BOARD=$(ARM_TRUSTED_FIRMWARE_TARGET_BOARD) \
+	HOSTCC="$(HOSTCC) $(HOST_LDFLAGS)"
 
 ifeq ($(BR2_TARGET_ARM_TRUSTED_FIRMWARE_SSP),y)
 ARM_TRUSTED_FIRMWARE_MAKE_OPTS += \
@@ -147,18 +148,6 @@ ARM_TRUSTED_FIRMWARE_MAKE_TARGETS = all
 ifeq ($(BR2_TARGET_ARM_TRUSTED_FIRMWARE_FIP),y)
 ARM_TRUSTED_FIRMWARE_MAKE_TARGETS += fip
 ARM_TRUSTED_FIRMWARE_DEPENDENCIES += host-openssl
-# fiptool only exists in newer (>= 1.3) versions of ATF, so we build
-# it conditionally. We need to explicitly build it as it requires
-# OpenSSL, and therefore needs to be passed proper variables to find
-# the host OpenSSL.
-define ARM_TRUSTED_FIRMWARE_BUILD_FIPTOOL
-	if test -d $(@D)/tools/fiptool; then \
-		$(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D)/tools/fiptool \
-			$(ARM_TRUSTED_FIRMWARE_MAKE_OPTS) \
-			CPPFLAGS="$(HOST_CPPFLAGS)" \
-			LDLIBS="$(HOST_LDFLAGS) -lcrypto" ; \
-	fi
-endef
 endif
 
 ifeq ($(BR2_TARGET_ARM_TRUSTED_FIRMWARE_RCW),y)
@@ -206,7 +195,6 @@ define ARM_TRUSTED_FIRMWARE_BUILD_CMDS
 	$(if $(ARM_TRUSTED_FIRMWARE_CUSTOM_DTS_PATH),
 		cp -f $(ARM_TRUSTED_FIRMWARE_CUSTOM_DTS_PATH) $(@D)/fdts/
 	)
-	$(ARM_TRUSTED_FIRMWARE_BUILD_FIPTOOL)
 	$(ARM_TRUSTED_FIRMWARE_MAKE_ENV) $(MAKE) -C $(@D) \
 		$(ARM_TRUSTED_FIRMWARE_MAKE_OPTS) \
 		$(ARM_TRUSTED_FIRMWARE_MAKE_TARGETS)
-- 
2.41.0