From 77f1f7a11738cece09d3e399e30f6106dc0f909a Mon Sep 17 00:00:00 2001
From: Varun Wadekar <vwadekar@nvidia.com>
Date: Thu, 31 Jan 2019 09:22:30 -0800
Subject: [PATCH] Introduce build option to override libc
This patch introduces a build option 'OVERRIDE_LIBC' that platforms
can set to override libc from the BL image. The default value is '0'
to keep the library.
Change-Id: I10a0b247f6a782eeea4a0359e30a8d79b1e9e4e1
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
---
Makefile | 9 ++++++++-
docs/user-guide.rst | 4 ++++
make_helpers/defaults.mk | 3 +++
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 0169f3f62..34f6890bb 100644
--- a/Makefile
+++ b/Makefile
@@ -248,7 +248,6 @@ DTC_CPPFLAGS += -nostdinc -Iinclude -undef -x assembler-with-cpp
# Common sources and include directories
################################################################################
include lib/compiler-rt/compiler-rt.mk
-include lib/libc/libc.mk
BL_COMMON_SOURCES += common/bl_common.c \
common/tf_log.c \
@@ -392,6 +391,13 @@ endif
endif
+################################################################################
+# Include libc if not overridden
+################################################################################
+ifeq (${OVERRIDE_LIBC},0)
+include lib/libc/libc.mk
+endif
+
################################################################################
# Check incompatible options
################################################################################
@@ -595,6 +601,7 @@ $(eval $(call assert_boolean,HANDLE_EA_EL3_FIRST))
$(eval $(call assert_boolean,HW_ASSISTED_COHERENCY))
$(eval $(call assert_boolean,MULTI_CONSOLE_API))
$(eval $(call assert_boolean,NS_TIMER_SWITCH))
+$(eval $(call assert_boolean,OVERRIDE_LIBC))
$(eval $(call assert_boolean,PL011_GENERIC_UART))
$(eval $(call assert_boolean,PROGRAMMABLE_RESET_ADDRESS))
$(eval $(call assert_boolean,PSCI_EXTENDED_STATE_ID))
diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index 3828eaff1..63b0f36ea 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -581,6 +581,10 @@ Common build options
1 (do save and restore). 0 is the default. An SPD may set this to 1 if it
wants the timer registers to be saved and restored.
+- ``OVERRIDE_LIBC``: This option allows platforms to override the default libc
+ for the BL image. It can be either 0 (include) or 1 (remove). The default
+ value is 0.
+
- ``PL011_GENERIC_UART``: Boolean option to indicate the PL011 driver that
the underlying hardware is not a full PL011 UART but a minimally compliant
generic UART, which is a subset of the PL011. The driver will not access
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index c1aa32052..76a9fd4fa 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -122,6 +122,9 @@ MULTI_CONSOLE_API := 0
# NS timer register save and restore
NS_TIMER_SWITCH := 0
+# Include lib/libc in the final image
+OVERRIDE_LIBC := 0
+
# Build PL011 UART driver in minimal generic UART mode
PL011_GENERIC_UART := 0
--
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