add linux kernel, custom patches and update Makefile

Makefile

@@ -10,13 +10,22 @@ DEPS := $(OBJS:.o=.d)
 INC_DIRS := $(shell find $(SRC_DIRS) -type d)
 INC_FLAGS := $(addprefix -I,$(INC_DIRS))
 
+Q=$(CURDIR)/buildroot-2021.05/output/host/bin/riscv32-buildroot-linux-gnu-
+
+CFLAGS=-g
+
 $(TARGET): $(OBJS)
 	$(CC) $(LDFLAGS) -I./elfy/elfy.h $(OBJS) -o $@ $(LOADLIBES) $(LDLIBS) -L./elfy/target/release/ -Wl,--no-as-needed -ldl -lpthread -lelfy
 
 .PHONY: clean
 clean:
-	$(RM) $(TARGET) $(OBJS) $(DEPS) fw_payload.*
+	$(RM) $(TARGET) $(OBJS) $(DEPS)
+
+.PHONY: distclean
+distclean: clean
+	$(RM) $(TARGET) $(OBJS) $(DEPS) *_payload.*
 	$(MAKE) -C opensbi clean
+	$(MAKE) -C linux clean
 
 -include $(DEPS)
 
@@ -24,28 +33,67 @@ clean:
 dts.dtb: dts.dts
 	dtc -o $@ $<
 
-OPENSBI_BUILD="opensbi/build/platform/generic/firmware"
+OPENSBI_BUILD=opensbi/build/platform/generic/firmware
-PAYLOAD="rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload.bin"
+PAYLOAD=rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload.bin
+LINUX_PAYLOAD=linux/arch/riscv/boot/Image
+
+BUILDROOT_MARKER=buildroot-2021.05/build.marker
+$(BUILDROOT_MARKER):
+	$(MAKE) -C buildroot-2021.05 make
+	cd buildroot-2021.05 && cp init output/target/ && cp pi.js output/target/
+	$(MAKE) -C buildroot-2021.05 make
+	touch $@
 
 $(PAYLOAD): $(shell find rust_payload/src -type f)
 	cd rust_payload; \
-		cargo +riscv32ima rustc -Zbuild-std --release --target "riscv32ima-unknown-none-elf" -- -Clink-arg=-Tlinker.ld -Clinker=riscv32-elf-ld
+		cargo +riscv32ima rustc -Zbuild-std --release --target "riscv32ima-unknown-none-elf" -- -Clink-arg=-Tlinker.ld -Clinker=$(Q)ld
-	riscv32-elf-objcopy -O binary \
+	$(Q)objcopy -O binary \
 		rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload $(PAYLOAD)
 
-fw_payload.bin: fw_payload.elf
+rust_payload.bin: rust_payload.elf
-	cp $(OPENSBI_BUILD)/fw_payload.bin .
+	cp $(OPENSBI_BUILD)/fw_payload.bin ./rust_payload.bin
-fw_payload.elf: $(PAYLOAD)
+rust_payload.elf: $(PAYLOAD) $(BUILDROOT_MARKER)
-	env CROSS_COMPILE=riscv64-elf- \
+	$(MAKE) -C opensbi clean
+	env CROSS_COMPILE=$(Q) \
 		PLATFORM=generic \
 		PLATFORM_RISCV_XLEN=32 \
 		PLATFORM_RISCV_ISA=rv32ima \
 		PLATFORM_RISCV_ABI=ilp32 \
 		FW_PAYLOAD_PATH=../$(PAYLOAD) \
 		FW_PIC=n \
-		ELFFLAGS=-L/usr/lib/gcc/riscv64-elf/10.2.0/rv32im/ilp32 \
 		$(MAKE) -C opensbi all
-	cp $(OPENSBI_BUILD)/fw_payload.elf .
+	cp $(OPENSBI_BUILD)/fw_payload.elf ./rust_payload.elf
+
+.PHONY: $(LINUX_PAYLOAD)
+$(LINUX_PAYLOAD): linux $(BUILDROOT_MARKER)
+	cd linux && (git am ../linux-_pi_-patches-for-rvc.patch || true)
+	cd linux && \
+		env CROSS_COMPILE=$(Q) \
+			CFLAGS="-march=rv32ima -mabi=ilp32" \
+			LDFLAGS="-march=rv32ima -mabi=ilp32" \
+			ARCH=riscv \
+			KCONFIG_ALLCONFIG=../linux.config \
+				make allnoconfig
+	cd linux && \
+		env CROSS_COMPILE=$(Q) \
+			CFLAGS="-march=rv32ima -mabi=ilp32" \
+			LDFLAGS="-march=rv32ima -mabi=ilp32" \
+			ARCH=riscv \
+				intercept-build make -j$(shell nproc)
+
+linux_payload.bin: linux_payload.elf
+	cp $(OPENSBI_BUILD)/fw_payload.bin ./linux_payload.bin
+linux_payload.elf: $(LINUX_PAYLOAD) $(BUILDROOT_MARKER)
+	$(MAKE) -C opensbi clean
+	env CROSS_COMPILE=$(Q) \
+		PLATFORM=generic \
+		PLATFORM_RISCV_XLEN=32 \
+		PLATFORM_RISCV_ISA=rv32ima \
+		PLATFORM_RISCV_ABI=ilp32 \
+		FW_PAYLOAD_PATH=../$(LINUX_PAYLOAD) \
+		FW_PIC=n \
+		$(MAKE) -C opensbi all
+	cp $(OPENSBI_BUILD)/fw_payload.elf ./linux_payload.elf
 
 .PHONY: run
 run: fw_payload.bin $(TARGET) dts.dtb

linux-_pi_-patches-for-rvc.patch

@@ -0,0 +1,128 @@
+From fbba62aff7a727723aa75715e1d1838b484ba842 Mon Sep 17 00:00:00 2001
+From: Stefan <stefan@pimaker.at>
+Date: Sun, 1 Aug 2021 20:58:20 +0200
+Subject: [PATCH] _pi_ patches for rvc
+
+* use MEMOP extension for faster memcpy (disabled atm)
+* don't poison init kernel area, we don't care about security
+* print more messages about initramfs loading, since otherwise it just
+  looks like it got stuck
+
+Signed-off-by: Stefan <stefan@pimaker.at>
+---
+ arch/riscv/lib/memcpy.S | 13 +++++++++++++
+ include/linux/mm.h      |  2 +-
+ init/initramfs.c        | 19 +++++++++++++++++--
+ 3 files changed, 31 insertions(+), 3 deletions(-)
+
+diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
+index 51ab716253fa..67636579413d 100644
+--- a/arch/riscv/lib/memcpy.S
++++ b/arch/riscv/lib/memcpy.S
+@@ -41,6 +41,18 @@ WEAK(memcpy)
+ 	beqz a4, 4f
+ 	add a3, a1, a4
+ 3:
++	#lla t0, 10f
++	#li t2, 1025
++	#bltu a2, t2, 11f
++
++	#csrw 0x0b1, a1 # src
++	#csrw 0x0b2, t6 # dst
++	#csrw 0x0b3, a2 # n
++	#li t2, 0x1
++	#csrw 0x0b0, t2 # memcpy
++	#j 10f
++
++11:
+ 	REG_L a4,       0(a1)
+ 	REG_L a5,   SZREG(a1)
+ 	REG_L a6, 2*SZREG(a1)
+@@ -76,6 +88,7 @@ WEAK(memcpy)
+ 	REG_S t1, 15*SZREG(t6)
+ 	addi t6, t6, 16*SZREG
+ 	bltu a1, a3, 3b
++10:
+ 	andi a2, a2, (16*SZREG)-1  /* Update count */
+ 
+ 4:
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 9afb8998e7e5..881f1c1cf7ea 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -2420,7 +2420,7 @@ static inline unsigned long free_initmem_default(int poison)
+ 	extern char __init_begin[], __init_end[];
+ 
+ 	return free_reserved_area(&__init_begin, &__init_end,
+-				  poison, "unused kernel");
++				  0x1ff, "unused kernel");
+ }
+ 
+ static inline unsigned long get_num_physpages(void)
+diff --git a/init/initramfs.c b/init/initramfs.c
+index af27abc59643..1124f0cf6c8f 100644
+--- a/init/initramfs.c
++++ b/init/initramfs.c
+@@ -43,8 +43,10 @@ static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
+ static __initdata char *message;
+ static void __init error(char *x)
+ {
+-	if (!message)
++	if (!message) {
+ 		message = x;
++		pr_err("[_pi_] initramfs error: %s\n", x);
++	}
+ }
+ 
+ static void panic_show_mem(const char *fmt, ...)
+@@ -467,6 +469,9 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
+ 	const char *compress_name;
+ 	static __initdata char msg_buf[64];
+ 
++	unsigned long len_orig = len;
++	unsigned long len_percent = 0, len_percent_tmp;
++
+ 	header_buf = kmalloc(110, GFP_KERNEL);
+ 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
+ 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
+@@ -474,11 +479,20 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
+ 	if (!header_buf || !symlink_buf || !name_buf)
+ 		panic_show_mem("can't allocate buffers");
+ 
++	pr_info("[_pi_] loading initramfs now, this may take a while...\n");
++
+ 	state = Start;
+ 	this_header = 0;
+ 	message = NULL;
+ 	while (!message && len) {
+ 		loff_t saved_offset = this_header;
++
++		len_percent_tmp = (len * 10) / len_orig;
++		if (len_percent_tmp != len_percent) {
++			len_percent = len_percent_tmp;
++			pr_info("[_pi_] initramfs: %lu0%% done\n", 10 - len_percent);
++		}
++
+ 		if (*buf == '0' && !(this_header & 3)) {
+ 			state = Start;
+ 			written = write_buffer(buf, len);
+@@ -494,7 +508,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
+ 		}
+ 		this_header = 0;
+ 		decompress = decompress_method(buf, len, &compress_name);
+-		pr_debug("Detected %s compressed data\n", compress_name);
++		pr_info("Detected %s compressed data\n", compress_name);
+ 		if (decompress) {
+ 			int res = decompress(buf, len, NULL, flush_buffer, NULL,
+ 				   &my_inptr, error);
+@@ -519,6 +533,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
+ 	kfree(name_buf);
+ 	kfree(symlink_buf);
+ 	kfree(header_buf);
++	pr_info("[_pi_] unpack_to_rootfs retval: %s\n", (message && *message) ? message : "<success>");
+ 	return message;
+ }
+ 
+-- 
+2.32.0
+

linux.config

@@ -0,0 +1,114 @@
+CONFIG_DEFAULT_HOSTNAME="rvc"
+CONFIG_LOCALVERSION="-rvc"
+
+CONFIG_RD_GZIP=n
+CONFIG_RD_BZIP2=n
+CONFIG_RD_LZMA=n
+CONFIG_RD_XZ=n
+CONFIG_RD_LZO=n
+CONFIG_RD_LZ4=n
+CONFIG_RD_ZSTD=n
+CONFIG_INITRAMFS_COMPRESSION_GZIP=n
+CONFIG_INITRAMFS_COMPRESSION_BZIP2=n
+CONFIG_INITRAMFS_COMPRESSION_LZMA=n
+CONFIG_INITRAMFS_COMPRESSION_XZ=n
+CONFIG_INITRAMFS_COMPRESSION_LZO=n
+CONFIG_INITRAMFS_COMPRESSION_LZ4=n
+CONFIG_INITRAMFS_COMPRESSION_ZSTD=n
+CONFIG_INITRAMFS_COMPRESSION_NONE=y
+
+CONFIG_INITRAMFS_SOURCE="../buildroot-2021.05/output/images/rootfs.cpio"
+
+CONFIG_BLK_DEV=y
+CONFIG_BLK_DEV_INITRD=y
+
+CONFIG_DEBUG=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_INFO=y
+
+CONFIG_32BIT=y
+CONFIG_ARCH_RV32I=y
+CONFIG_RISCV_ISA_C=n
+CONFIG_MMU=y
+CONFIG_RISCV_M_MODE=n
+CONFIG_RISCV_SBI=y
+CONFIG_SMP=n
+CONFIG_BROKEN_ON_SMP=y
+CONFIG_FPU=n
+CONFIG_NUMA=n
+CONFIG_EFI=n
+CONFIG_MULTIUSER=n
+
+CONFIG_PRINTK=y
+CONFIG_PRINTK_TIME=y
+CONFIG_EARLY_PRINTK=y
+
+CONFIG_RISCV_SBI_V01=y
+CONFIG_SERIAL_EARLYCON_RISCV_SBI=y
+CONFIG_HVC_RISCV_SBI=y
+
+CONFIG_BINFMT_ELF=y
+CONFIG_ELFCORE=y
+CONFIG_BINFMT_SCRIPT=y
+CONFIG_BINFMT_FLAT=y
+CONFIG_BINFMT_MISC=y
+
+CONFIG_TTY=y
+CONFIG_VT=y
+CONFIG_VT_CONSOLE=y
+CONFIG_VT_HW_CONSOLE_BINDING=y
+CONFIG_SERIAL_CORE=y
+CONFIG_SERIAL_CORE_CONSOLE=y
+CONFIG_SERIAL_8250=n
+CONFIG_SERIAL_8250_CONSOLE=n
+CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SERIAL_EARLYCON=y
+CONFIG_CONSOLE_POLL=n
+CONFIG_UNIX98_PTYS=n
+CONFIG_LEGACY_PTYS=n
+
+CONFIG_RISCV_TIMER=y
+CONFIG_PREEMPT_NONE=y
+
+CONFIG_DTC=y
+CONFIG_OF=y
+CONFIG_OF_FLATTREE=y
+CONFIG_OF_EARLY_FLATTREE=y
+CONFIG_OF_KOBJ=y
+CONFIG_OF_ADDRESS=y
+CONFIG_OF_IRQ=y
+CONFIG_OF_RESERVED_MEM=y
+
+CONFIG_RAMFS=y
+CONFIG_TMPFS=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_PROC_FS=y
+CONFIG_SYSFS=y
+CONFIG_EXPORTFS=n
+
+CONFIG_MSDOS_PARTITION=n
+CONFIG_EFI_PARTITION=n
+CONFIG_FW_LOADER=n
+CONFIG_SCSI_MOD=n
+CONFIG_BLK_DEV_BSG=n
+CONFIG_MQ_IOSCHED_KYBER=n
+CONFIG_MQ_IOSCHED_DEADLINE=n
+CONFIG_IO_WQ=n
+CONFIG_SERIAL_8250_16550A_VARIANTS=n
+CONFIG_SERIAL_8250_NR_UARTS=1
+CONFIG_SERIAL_8250_RUNTIME_UARTS=1
+CONFIG_VGA_CONSOLE=n
+CONFIG_HID=n
+CONFIG_USB_SUPPORT=n
+CONFIG_EDAC_SUPPORT=n
+CONFIG_IOMMU_SUPPORT=n
+CONFIG_HAVE_EBPF_JIT=n
+CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR=n
+CONFIG_DEFAULT_SECURITY_DAC=n
+CONFIG_PCI=n
+CONFIG_USB=n
+
+CONFIG_HAVE_SYSCALL_TRACEPOINTS=n
+CONFIG_TRACING_SUPPORT=n
+CONFIG_FTRACE=n