riscv XIP kernel

At the moment, it was only tested on Microchip Polarfire SoC.

Quick way

  1. Download SD card image from

     $ wget
  2. Hart Software Services

    Follow instructions here (you can use .config based on 0.99.15 as I had some issues building it).

  3. Linux kernel

    Build using the config here: .config

    This can be derived from defconfig by using the following command:

     $ tuxmake --verbose --build-dir riscv_rv64_xipkernel --directory /home/alex/wip/linux --target-arch riscv --kconfig defconfig config --kconfig-add CONFIG_DEBUG_KERNEL=y --kconfig-add CONFIG_DEBUG_INFO=y --kconfig-add CONFIG_GDB_SCRIPTS=y --kconfig-add CONFIG_PCI=n --kconfig-add CONFIG_SPARSEMEM_MANUAL=y --kconfig-add CONFIG_DEBUG_VM_PGTABLE=n --kconfig-add CONFIG_XIP_KERNEL=y
  4. Launching using qemu

    Support for Polarfire in qemu is recent, more instructions can be found here: qemu Polarfire

    Use the following command line (adapting the path):

     $ qemu-system-riscv64                                               					\
         -M microchip-icicle-kit                                         					\
         -bios hart-software-services/Default/hss.bin                                				\
         -smp 5 -display none -nic user,model=cadence_gem -serial null                       			\
         -chardev socket,id=serial1,path=/tmp/serial1.sock,server -serial chardev:serial1            		\
         -drive if=sd,format=raw,file=core-image-minimal-dev-icicle-kit-es-sd-20210216171231.rootfs.wic.gz   	\
         -device loader,addr=0x21000000,file=arch/riscv/boot/xipImage                        			\
         -m 6G -D qemu.log -monitor stdio -s

    Launch the following to connect to the serial output:

     $ sudo minicom -D unix#/tmp/serial1.sock

    In uboot console, launch the XIP kernel using the following command:

     RISC-V # go 0x21000000

    And in parallel, you can launch gdb using the following gdb commands:

     (gdb) target extended-remote :1234
     (gdb) add-inferior
     (gdb) inferior 2
     (gdb) attach 2
     (gdb) set schedule-multiple
     (gdb) info threads

    Generally I don’t have any output in minicom from the kernel (I have not found why yet). But I can see kernel messages by compiling the kernel with following config:


    And by using the following command in gdb:

     (gdb) file vmlinux
     (gdb) lx-dmesg

Long way (never tested)