QEMU's integrated OpenSBI supports writing to console, but the one I compiled doesn't

[saraelsa]

I built OpenSBI (main branch) on macOS arm64 using the following command:

Code: Select all

make LLVM=1 PLATFORM=GENERIC

The following two files it generates are of interest:

• build/platform/generic/firmware/payloads/test.bin
• build/platform/generic/firmware/fw_jump.bin

I can run the test.bin payload using the following command:

Code: Select all

qemu-system-riscv64 -nographic -M virt -smp 1 -m 512M -kernel ./build/platform/generic/firmware/payloads/test.elf

It outputs "Test payload running" and then goes into a low-power infinite loop.

However, I can't get it to work with the OpenSBI binary I just built. I tried the following command for that purpose:

Code: Select all

qemu-system-riscv64 -nographic -M virt -smp 1 -m 512M -bios ./build/platform/generic/firmware/fw_jump.bin -kernel ./build/platform/generic/firmware/payloads/test.bin

I confirmed with lldb that it does work—in that all expected breakpoints are hit and it eventually ends up in the infinite loop—but it doesn't generate the output string.

In both cases, I can see OpenSBI's output printed.

What could the problem be?

[Octocontrabass]

OpenSBI (main branch)

Are you sure the main branch works? QEMU uses release versions of OpenSBI.

Code: Select all

make LLVM=1 PLATFORM=GENERIC

Is it case-sensitive? Maybe it needs to be "PLATFORM=generic" to build correctly.

fw_jump.bin

Have you tried fw_dynamic.bin? It shouldn't make a difference, but that's the one QEMU uses.

[saraelsa]

OpenSBI (main branch)

Are you sure the main branch works? QEMU uses release versions of OpenSBI.

Code: Select all

make LLVM=1 PLATFORM=GENERIC

Is it case-sensitive? Maybe it needs to be "PLATFORM=generic" to build correctly.

fw_jump.bin

Have you tried fw_dynamic.bin? It shouldn't make a difference, but that's the one QEMU uses.

I tried compiling with lowercase 'generic' from branch release-1.5.x and loading fw_dynamic.bin. I get the same result.

I should note that OpenSBI itself prints a lot of output. It's only the payload that isn't able to print anything.