Makefile

################################################################################
# Copyright (c) 2018 Intel Corporation
#
# 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.
################################################################################

export PROJS = $(CURDIR)

export BUILD_DIR ?= $(PROJS)/out/

export CC = $(COMPILE_TOOLCHAIN)gcc
export AS = $(COMPILE_TOOLCHAIN)gcc
export LD = $(COMPILE_TOOLCHAIN)ld

CFLAGS = -O2 -std=gnu99

# product position indepent code for relocation.
CFLAGS += -fPIC

# print error type like [-Werror=packed].
CFLAGS += -fdiagnostics-show-option

# without this flag, the highest bit will be treated as sign bit
# e.g. int a:2 = 3, but it's printf("%d", a) is -1.
CFLAGS += -funsigned-bitfields

# the program running on the 64bit extension Pentium 4 CPU.
CFLAGS += -m64 -march=nocona

# if function don't need frame-pointer(rbp), don't store it in a register.
CFLAGS += -fomit-frame-pointer

# don't need extended instruction sets.
CFLAGS += -mno-mmx -mno-sse -mno-sse2 -mno-sse3 -mno-3dnow

# don't link dynamic library and don't rely on standard library.
CFLAGS += -static -nostdinc -fno-hosted

# add warning checks as much as possible.
# -Wconversion option will cause a warning like i += 1, so we strip this
# warning option
CFLAGS += -Wall -Wextra -Werror -Wbad-function-cast -Wpacked -Wpadded \
	-Winit-self -Wswitch-default -Wtrampolines -Wdeclaration-after-statement \
	-Wredundant-decls -Wnested-externs -Winline -Wstack-protector \
	-Woverlength-strings -Wlogical-op -Waggregate-return \
	-Wmissing-field-initializers -Wpointer-arith -Wcast-qual \
	-Wcast-align -Wwrite-strings

CFLAGS += -I.

CFLAGS += -fno-stack-protector

AFLAGS = -fPIC -static -nostdinc
# treat warnings as errors
AFLAGS += -Wa,--fatal-warnings

export CFLAGS
export AFLAGS

ifneq ($(BUILD_DIR), $(wildcard $(BUILD_DIR)))
$(shell mkdir -p $(BUILD_DIR))
endif

TARGET = trusty_loader.elf

CSOURCES = $(wildcard *.c)
ASOURCES = $(wildcard *.S)

include $(PROJS)/rule.linux

LDFLAGS = -T linker.lds -z max-page-size=4096 -z common-page-size=4096

all: $(TARGET) trusty_loader.bin

$(TARGET):
	$(LD) $(LDFLAGS) -o $(BUILD_DIR)$@ $(wildcard $(BUILD_DIR)*.o)

trusty_loader.bin: $(TARGET)
	objcopy -j .text -O binary -S $(BUILD_DIR)$(TARGET) $(BUILD_DIR)trusty_loader.bin

clean:
	-rm -rf $(BUILD_DIR)