From: TANG Tiancheng <tangtiancheng....@alibaba-inc.com> This patch set aims to expose 32-bit RISC-V cpu to RV64 QEMU. Thus qemu-system-riscv64 can directly boot a RV32 Linux.
This patch set has been tested with 6.9.0 Linux Image. - Run RV64 QEMU with RV32 CPU qemu-system-riscv64 -cpu rv32 -M virt -nographic \ -kernel Image \ -append "root=/dev/vda ro console=ttyS0" \ -drive file=rootfs.ext2,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 -netdev user,id=net0 \ -device virtio-net-device,netdev=net0 OpenSBI v1.4 QEMU emulator version 9.0.50 (v9.0.0-1132-g7799dc2e3b) [ 0.000000] Linux version 6.9.0 (developer@11109ca35736) (riscv32-unknown-linux-gnu-gcc (gc891d8dc23e-dirty) 13.2.0, GNU ld (GNU Binutils) 2.42) #3 SMP Fri May 31 08:42:15 UTC 2024 [ 0.000000] random: crng init done [ 0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80400000 [ 0.000000] Machine model: riscv-virtio,qemu [ 0.000000] SBI specification v2.0 detected [ 0.000000] SBI implementation ID=0x1 Version=0x10004 [ 0.000000] SBI TIME extension detected [ 0.000000] SBI IPI extension detected [ 0.000000] SBI RFENCE extension detected [ 0.000000] SBI SRST extension detected [ 0.000000] SBI DBCN extension detected [ 0.000000] efi: UEFI not found. [ 0.000000] OF: reserved mem: 0x80000000..0x8003ffff (256 KiB) nomap non-reusable mmode_resv1@80000000 [ 0.000000] OF: reserved mem: 0x80040000..0x8004ffff (64 KiB) nomap non-reusable mmode_resv0@80040000 [ 0.000000] Zone ranges: [ 0.000000] Normal [mem 0x0000000080400000-0x0000000087ffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000080400000-0x0000000087ffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000080400000-0x0000000087ffffff] [ 0.000000] On node 0, zone Normal: 1024 pages in unavailable ranges [ 0.000000] SBI HSM extension detected [ 0.000000] riscv: base ISA extensions acdfhim [ 0.000000] riscv: ELF capabilities acdfim [ 0.000000] percpu: Embedded 17 pages/cpu s37728 r8192 d23712 u69632 [ 0.000000] Kernel command line: root=/dev/vda ro console=ttyS0 [ 0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear) [ 0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear) [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 31465 [ 0.000000] mem auto-init: stack:all(zero), heap alloc:off, heap free:off [ 0.000000] Virtual kernel memory layout: [ 0.000000] fixmap : 0x9c800000 - 0x9d000000 (8192 kB) [ 0.000000] pci io : 0x9d000000 - 0x9e000000 ( 16 MB) [ 0.000000] vmemmap : 0x9e000000 - 0xa0000000 ( 32 MB) [ 0.000000] vmalloc : 0xa0000000 - 0xc0000000 ( 512 MB) [ 0.000000] lowmem : 0xc0000000 - 0xc7c00000 ( 124 MB) [ 0.000000] Memory: 95700K/126976K available (9090K kernel code, 8845K rwdata, 4096K rodata, 4231K init, 341K bss, 31276K reserved, 0K cma-reserved) ... Welcome to Buildroot buildroot login: root # cat /proc/cpuinfo processor : 0 hart : 0 isa : rv32imafdch_zicbom_zicboz_zicntr_zicsr_zifencei_zihintntl_zihintpause_zihpm_zfa_zba_zbb_zbc_zbs_sstc mmu : sv32 TANG Tiancheng (6): target/riscv: Add fw_dynamic_info32 for booting RV32 OpenSBI target/riscv: Adjust PMP size for no-MMU RV64 QEMU running RV32 target/riscv: Correct SXL return value for RV32 in RV64 QEMU target/riscv: Detect sxl to set bit width for RV32 in RV64 target/riscv: Correct mcause/scause bit width for RV32 in RV64 QEMU target/riscv: Enable RV32 CPU support in RV64 QEMU configs/targets/riscv64-softmmu.mak | 2 +- hw/riscv/boot.c | 35 +++++++++++++++++++---------- hw/riscv/sifive_u.c | 3 ++- include/hw/riscv/boot.h | 4 +++- include/hw/riscv/boot_opensbi.h | 29 ++++++++++++++++++++++++ target/riscv/cpu.c | 17 ++++++++++---- target/riscv/cpu.h | 5 ++++- target/riscv/cpu_helper.c | 23 ++++++++++++++----- target/riscv/pmp.c | 2 +- 9 files changed, 93 insertions(+), 27 deletions(-) -- 2.43.0