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| author | Miquel Sabaté Solà <mikisabate@gmail.com> | 2024-11-29 22:17:13 +0100 |
|---|---|---|
| committer | Miquel Sabaté Solà <mikisabate@gmail.com> | 2024-11-29 22:17:13 +0100 |
| commit | d51665904faa31c39106e4b2afa7541615072e72 (patch) | |
| tree | 01c355472bcca04f59980d961dca0bc46c9b429b /Makefile | |
| parent | 010888de490ab1fafc0200c37cd09d57a0ff1e9f (diff) | |
| download | fbos-d51665904faa31c39106e4b2afa7541615072e72.tar.gz fbos-d51665904faa31c39106e4b2afa7541615072e72.zip | |
Allow the kernel to run as a Linux image
In order to run on real hardware, it's actually easier to re-use
workflows from existing bootloaders than loading things in memory
manually. In order to achieve this two things had to be settled:
1. The image has to have a Linux header as defined in the RISC-V port.
This header will be taken into consideration by bootloaders in order to
know where to jump, the image offset, the endianness of the image, etc.
2. The image cannot just be an ELF executable. Rather, we must translate
it into binary form via `objcopy`.
With all of this at hand, I was able to make the kernel run on a
Starfive VisionFive 2 board, and I have recorded an example so it's
available as documentation.
Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 24 |
1 files changed, 16 insertions, 8 deletions
@@ -20,7 +20,8 @@ endif CC = $(CROSS_COMPILE)gcc$(CC_SUFFIX) LD = $(CROSS_COMPILE)ld HOSTCC = gcc$(CC_SUFFIX) -QEMU ?= qemu-system-riscv64 +QEMU ?= qemu-system-riscv64 +OBJCPY = $(CROSS_COMPILE)objcopy ISA ?= rv64imafdc_zicntr_zicsr_zifencei_zihpm_zca_zcd_zba_zbb ASFLAGS = -march=$(ISA) -mabi=lp64d -mcmodel=medany -fno-PIE @@ -59,7 +60,8 @@ endif SRC = $(filter-out kernel/fbos.ld.S, $(wildcard kernel/*.S kernel/*.c lib/*.c lib/*.S)) OBJ = $(patsubst %.c,%.o,$(patsubst %.S,%.o,$(SRC))) LINKER = kernel/fbos.ld -KRNL = fbos +IMAGE = fbos +KRNL = $(IMAGE).elf USR = usr/bin/init usr/bin/fizz usr/bin/buzz usr/bin/fizzbuzz INIT = usr/initramfs.cpio TESTS = test/test_dt test/test_initrd @@ -71,7 +73,13 @@ LDFLAGS += -T $(LINKER) # Kernel .PHONY: all -all: clean $(KRNL) usr test +all: clean $(IMAGE) usr test + +.PHONY: $(IMAGE) +$(IMAGE): $(KRNL) + $(E) " OBJCOPY " $@ + $(Q) $(OBJCPY) $(KRNL) -O binary $(IMAGE) + $(Q) rm $(KRNL) .PHONY: $(KRNL) $(KRNL): $(OBJ) $(LINKER).S @@ -134,7 +142,7 @@ test/%: test/%.o .PHONY: archive archive: all $(Q) $(eval DIR := $(shell mktemp -d)) - $(Q) mkdir -p $(DIR)/fbos && cp $(KRNL) $(INIT) $(DIR)/fbos/ + $(Q) mkdir -p $(DIR)/fbos && cp $(IMAGE) $(INIT) $(DIR)/fbos/ $(Q) cd $(DIR) && tar czf $(ARCHIVE) fbos/ $(Q) cp $(DIR)/$(ARCHIVE) . $(E) " TAR $(ARCHIVE)" @@ -143,11 +151,11 @@ archive: all # Hacking .PHONY: qemu -qemu: clean $(KRNL) usr +qemu: clean $(IMAGE) usr ifeq ($(strip $(QEMU_BIOS)),) - $(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -kernel $(KRNL) -initrd $(INIT) + $(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -kernel $(IMAGE) -initrd $(INIT) else - $(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -bios $(QEMU_BIOS) -kernel $(KRNL) -initrd $(INIT) + $(Q) $(QEMU) $(QEMU_FLAGS) -machine virt -bios $(QEMU_BIOS) -kernel $(IMAGE) -initrd $(INIT) endif .PHONY: gdb @@ -156,7 +164,7 @@ gdb: .PHONY: clean clean: - $(Q) rm -rf $(OBJ) $(KRNL) $(LINKER) $(USR) usr/src/*.o $(INIT) test/*.o test/lib/*.o $(TESTS) $(ARCHIVE) + $(Q) rm -rf $(OBJ) $(KRNL) $(IMAGE) $(LINKER) $(USR) usr/src/*.o $(INIT) test/*.o test/lib/*.o $(TESTS) $(ARCHIVE) .PHONY: lint lint: |