Bootstrap the project

For now the base layout has been defined and we have a binary that is
properly reached through openSBI.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..f969a1c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,90 @@
+##
+# By default everything is silent. If you want to change this behavior, simply
+# assign V=1 when calling make.
+
+V =
+ifeq ($(strip $(V)),)
+	E = @echo
+	Q = @
+else
+	E = @\#
+	Q =
+endif
+
+##
+# Compile options. You can use CROSS_COMPILE just like on the Linux Kernel. You
+# can also determine the ISA to be used, which defaults to my VisionFive2 board.
+# I did not go too much into the rabbit hole of platform-specific flags. Hence
+# no `-mcpu`, no `-mtune`, no funny business.
+
+CC   = $(CROSS_COMPILE)gcc
+LD   = $(CROSS_COMPILE)ld
+QEMU ?= qemu-system-riscv64
+
+ISA        ?= rv64imafdc_zicntr_zicsr_zifencei_zihpm_zca_zcd_zba_zbb
+CCFLAGS     = -march=$(ISA) -Iinclude/ -mabi=lp64
+CCFLAGS    += -Werror -Wpedantic -Wall -Wextra -Wcast-align -Wcast-qual -Winit-self \
+              -Wmissing-include-dirs -Wredundant-decls -Wshadow -Wsign-conversion \
+              -Wswitch-default -Wundef -Wunreachable-code -Wmissing-noreturn
+LDFLAGS     = -Iinclude/ -static -nostdlib -melf64lriscv -z noexecstack
+QEMU_FLAGS ?=
+QEMU_BIOS  ?=
+
+##
+# You can pass an optional `DEBUG` variable to manipulate the build type. This
+# will also affect how QEMU is run.
+
+DEBUG =
+ifeq ($(strip $(DEBUG)),)
+	CCFLAGS += -O3
+else
+	CCFLAGS += -g
+	QEMU_FLAGS += -s -S
+endif
+
+##
+# Paths.
+
+SRC    = $(wildcard kernel/head.S kernel/*.c)
+OBJ    = $(patsubst %.c,%.o,$(patsubst %.S,%.o,$(SRC)))
+LINKER = kernel/fbos.ld
+KRNL   = fbos
+
+LDFLAGS += -T $(LINKER)
+
+##
+# Targets
+
+.PHONY: all
+all: clean $(KRNL)
+
+.PHONY: $(KRNL)
+$(KRNL): $(OBJ) $(LINKER).S
+	$(Q) $(CC) -E $(LINKER).S -Iinclude/ -o $(LINKER)
+
+	$(E) "	LD	" $@
+	$(Q) $(LD) $(LDFLAGS) $(OBJ) -o $(KRNL)
+
+.c.o:
+	$(E) "	CC	" $(*F)
+	$(Q) $(CC) $(CCFLAGS) -c $< -o $@
+
+.S.o:
+	$(E) "	CC	" $(*F)
+	$(Q) $(CC) $(CCFLAGS) -c $< -o $@
+
+.PHONY: qemu
+qemu:
+ifeq ($(strip $(QEMU_BIOS)),)
+	$(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -kernel $(KRNL) -nographic
+else
+	$(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -bios $(QEMU_BIOS) -kernel $(KRNL) -nographic
+endif
+
+.PHONY: gdb
+gdb:
+	$(Q) gdb --command utils/init.gdb
+
+.PHONY: clean
+clean:
+	$(Q) rm -f $(OBJ) $(KRNL) $(LINKER)