RISC-V Spike Simulator SDK

In the recent version of the riscv-tools and freedom-u-sdk, both of them removed the support of the spike simulator, and tutorials about running Linux on spike is using static compiled busybox, which is not suitable for real test environments. Spike is the simplest simulator of RISC-V, it has a very clear description of the instructions, you can apply your ideas and check it for a quick try. The RISC-V Spike Simulator SDK wants to help people to test design with 64-bit Linux environment on Spike easily, the basic framework is based on Freedom U SDK version 1.0.

This SDK will provide great convenience for the following people who:

• want to run upstream version Linux on Spike
• want to test design in Linux environment with modified spike, gcc and other extension in toolchain
• want to have a overview about embedded system development

This SDK follows the newest Linux Kernel, GNU toolchain and Spike, the functions of each folder in the project are as follows:

Folder	Description	Version
repo/buildroot	Build initramfs	2023.8.x
repo/linux	Linux Kernel	6.6.2
repo/riscv-gnu-toolchain	GNU Compiler Toolchain	gcc 13.2.0 ld 2.41
repo/riscv-(isa-sim,pk)	Simulator & Bootloader	master
repo/opensbi	Supervisor / Bootloader	master
conf	config for SDK

Quickstart

Build dependencies on Ubuntu 16.04/18.04:

$ sudo apt-get install device-tree-compiler autoconf automake autotools-dev    \
curl libmpc-dev libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo \
gperf libtool patchutils bc zlib1g-dev libexpat-dev python-dev python3-dev unzip \
libglib2.0-dev libpixman-1-dev git rsync wget cpio

git clone https://github.com/riscv-zju/riscv-rss-sdk.git

# For people who only want to have a try
sh quickstart.sh
# For people who want to develop the whole system
git submodule update --init --recursive --progress

#	NOTICE: 
# 		If you already have a riscv toolchain, please notice ** DO NOT SET
#		 $RISCV and MAKE SURE NO ORIGIN RISCV TOOLCHAIN IN YOUR $PATH **
make

Software Development

The default process will only build Linux cross-compiler, which has prefix "riscv64-unknown-linux", if you want using newlib, you can use make newlib to build, then you can use pk as a kernel to run your program.

The main compile process will run vmlinux on spike directly, to add your test program, you should add your elfs in ./work/buildroot_initramfs_sysroot and make again.

NOTICE: The test program should use Linux cross-compiler to compile , instead of Newlib cross-compiler.

If the benchmark you choose need some package, you can use make buildroot_initramfs-menuconfig to reconfigure buildroot and touch buildroot && make to rebuild.

Same to linux, if you want to add driver for new devices, make linux-menuconfig to reconfigure, touch linux && make to rebuild.

If you want to build step by step ...

1. Build RISC-V GNU Toolchain

   The key to build the dynamic link elf is using the correspond kernel version header to build the gnu toolchain. And if you want to use this SDK to do some development on your own chip, you may also need to change ARCH@ABI.

2. Build rootfs
   Using buildroot to help you to build a rootfs, you can add config in conf/buildroot_initramfs_config to add package, and you can copy your pre-compiled elf to rootfs/initramfs_sysroot to access in Spike. And remember, the basic idea of this SDK is to deconfig all the device, because spike is very limited support for devices, specically the Ethernet, so you should not open DHCP.

3. Compile Linux
   You can find config in work/linux_defconfig.

4. Bootloader You can choose between bbl or opensbi to use as bootloader to launch the simulation. Either edit the default in the Makefile or launch

   # default
   BL=opensbi make
   # or
   BL=bbl make

5. Spike The default account is root, following is the terminal log on Linux 5.8.0.

bbl loader

		  RISC-V Spike Simulator SDK
	  This SDK is based on SiFive Freedom U SDK.                    
	      ___           ___           ___     
	     /\  \         /\  \         /\  \    
	    /  \  \       /  \  \       /  \  \   
	   / /\ \  \     / /\ \  \     / /\ \  \  
	  /  \~\ \  \   _\ \~\ \  \   _\ \~\ \  \ 
	 / /\ \ \ \__\ /\ \ \ \ \__\ /\ \ \ \ \__\
	 \/_|  \/ /  / \ \ \ \ \/__/ \ \ \ \ \/__/
	    | |  /  /   \ \ \ \__\    \ \ \ \__\  
	    | |\/__/     \ \/ /  /     \ \/ /  /  
	    | |  |        \  /  /       \  /  /   
	     \|__|         \/__/         \/__/ 
     
     
[    0.000000] OF: fdt: No chosen node found, continuing without
[    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
[    0.000000] Linux version 5.8.0 (phantom@ubuntu-phantom) (riscv64-unknown-linux-gnu-gcc (GCC) 10.1.0, GNU ld (GNU Binutils) 2.34) #1 SMP Sun Aug 9 00:00:03 CST 2020
[    0.000000] Zone ranges:
[    0.000000]   DMA32    [mem 0x0000000080200000-0x00000000ffffffff]
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080200000-0x00000000ffffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x00000000ffffffff]
[    0.000000] software IO TLB: mapped [mem 0xfa3fb000-0xfe3fb000] (64MB)
[    0.000000] SBI specification v0.1 detected
[    0.000000] riscv: ISA extensions acdfim
[    0.000000] riscv: ELF capabilities acdfim
[    0.000000] percpu: Embedded 14 pages/cpu s24664 r0 d32680 u57344
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 516615
[    0.000000] Kernel command line: 
[    0.000000] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes, linear)
[    0.000000] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
[    0.000000] Sorting __ex_table...
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] Memory: 1982360K/2095104K available (3640K kernel code, 2736K rwdata, 2048K rodata, 4916K init, 259K bss, 112744K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] rcu: Hierarchical RCU implementation.
[    0.000000] rcu: 	RCU event tracing is enabled.
[    0.000000] rcu: 	RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
[    0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[    0.000000] riscv-intc: 64 local interrupts mapped
[    0.000000] riscv_timer_init_dt: Registering clocksource cpuid [0] hartid [0]
[    0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x24e6a1710, max_idle_ns: 440795202120 ns
[    0.000005] sched_clock: 64 bits at 10MHz, resolution 100ns, wraps every 4398046511100ns
[    0.011900] printk: console [hvc0] enabled
[    0.012150] Calibrating delay loop (skipped), value calculated using timer frequency.. 20.00 BogoMIPS (lpj=100000)
[    0.012755] pid_max: default: 32768 minimum: 301
[    0.013100] Mount-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.013535] Mountpoint-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
[    0.014735] rcu: Hierarchical SRCU implementation.
[    0.015270] smp: Bringing up secondary CPUs ...
[    0.016900] smp: Brought up 1 node, 4 CPUs
[    0.017455] devtmpfs: initialized
[    0.018045] random: get_random_bytes called from setup_net+0x38/0x186 with crng_init=0
[    0.018085] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.019110] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
[    0.019670] NET: Registered protocol family 16
[    0.022850] vgaarb: loaded
[    0.023135] SCSI subsystem initialized
[    0.023575] usbcore: registered new interface driver usbfs
[    0.023910] usbcore: registered new interface driver hub
[    0.024280] usbcore: registered new device driver usb
[    0.024945] clocksource: Switched to clocksource riscv_clocksource
[    0.026170] NET: Registered protocol family 2
[    0.026690] tcp_listen_portaddr_hash hash table entries: 1024 (order: 2, 16384 bytes, linear)
[    0.027200] TCP established hash table entries: 16384 (order: 5, 131072 bytes, linear)
[    0.027845] TCP bind hash table entries: 16384 (order: 6, 262144 bytes, linear)
[    0.028465] TCP: Hash tables configured (established 16384 bind 16384)
[    0.028880] UDP hash table entries: 1024 (order: 3, 32768 bytes, linear)
[    0.029300] UDP-Lite hash table entries: 1024 (order: 3, 32768 bytes, linear)
[    0.029795] NET: Registered protocol family 1
[    0.030055] PCI: CLS 0 bytes, default 64
[    0.043200] workingset: timestamp_bits=62 max_order=19 bucket_order=0
[    0.047435] io scheduler mq-deadline registered
[    0.047700] io scheduler kyber registered
[    0.088725] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[    0.090115] libphy: Fixed MDIO Bus: probed
[    0.090550] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    0.090930] ehci-pci: EHCI PCI platform driver
[    0.091230] usbcore: registered new interface driver usb-storage
[    0.091720] usbcore: registered new interface driver usbhid
[    0.092045] usbhid: USB HID core driver
[    0.092405] NET: Registered protocol family 17
[    0.093925] Freeing unused kernel memory: 4916K
[    0.095115] Run /init as init process
Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Starting network: OK

Welcome to Buildroot
buildroot login: root
root
# cd /
cd /
# ls
ls
bin      init     linuxrc  opt      run      tmp
dev      lib      media    proc     sbin     usr
etc      lib64    mnt      root     sys      var
# poweroff
poweroff
# Stopping network: OK
Stopping klogd: OK
Stopping syslogd: OK
umount: can't unmount /: Invalid argument
The system is going down NOW!
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system poweroff
[   14.925145] reboot: Power down

6. Debug You can use the openocd to debug our FPGA by the following openocd configuration file conf/starship.cfg

   	adapter speed 1000
   	adapter driver ftdi
   	ftdi vid_pid 0x0403 0x6010
   	ftdi channel 0
   	ftdi layout_init 0x00e8 0x60eb
   	reset_config none
   	transport select jtag
   	set _CHIPNAME riscv
   	jtag newtap $_CHIPNAME cpu -irlen 5
   
   	set _TARGETNAME $_CHIPNAME.cpu
   
   	target create $_TARGETNAME.0 riscv -chain-position $_TARGETNAME
   	$_TARGETNAME.0 configure -work-area-phys 0x80000000 -work-area-size 10000 -work-area-backup 1
   	riscv use_bscan_tunnel 0
   

   This configuration has been proved validly on VC707 and FTDI2332. The vid_pid is the vendor id and product id of the FTDI device, and you can get this paramter by run lsusb The ftdi channel is the channel id of the jtag channel while the ftdi USB device has 4 channel If your connection between jtag port and debug board is correct, when you run openocd -f conf/starship.cfg, the following output means your openocd connects the fpga debug module successfully.

   	Open On-Chip Debugger 0.12.0+dev-g4559b4790 (2023-12-14-15:22)
   	Licensed under GNU GPL v2
   	For bug reports, read
   			http://openocd.org/doc/doxygen/bugs.html
   	Info : Nested Tap based Bscan Tunnel Selected
   	Info : Listening on port 6666 for tcl connections
   	Info : Listening on port 4444 for telnet connections
   	Info : clock speed 1000 kHz
   	Info : JTAG tap: riscv.cpu tap/device found: 0x00000001 (mfg: 0x000 (<invalid>), part: 0x0000, ver: 0x0)
   	Info : [riscv.cpu.0] datacount=2 progbufsize=16
   	Info : [riscv.cpu.0] Disabling abstract command reads from CSRs.
   	Info : [riscv.cpu.0] Disabling abstract command writes to CSRs.
   	Info : [riscv.cpu.0] Examined RISC-V core; found 1 harts
   	Info : [riscv.cpu.0]  XLEN=64, misa=0x800000000094112d
   	[riscv.cpu.0] Target successfully examined.
   	Info : starting gdb server for riscv.cpu.0 on 3333
   	Info : Listening on port 3333 for gdb connections
   

   Then you can use gdb to debug fpga by remote connecting the 3333 port.

Finally, if you have any suggestions for this SDK, please push it !