For the test implementation of the SuperH architecture a second serial
serial port needs to be used. Unfortunately the currently used 'stdio'
driver does not support multiple serial ports at the same time.

Switch to the 'file' driver which does support multiple ports and is
sufficient for the nolibc-test usecase.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 tools/testing/selftests/nolibc/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 22da78a4bfea0274f66abec319d34b3d2a2824ac..238acaa7bb06dcdbcadd9d3190c2de726e1a40b1 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -315,12 +315,12 @@ kernel-standalone: initramfs | defconfig
 
 # run the tests after building the kernel
 run: kernel initramfs.cpio
-	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial file:/dev/stdout $(QEMU_ARGS) > "$(CURDIR)/run.out"
 	$(Q)$(REPORT) $(CURDIR)/run.out
 
 # re-run the tests from an existing kernel
 rerun:
-	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial file:/dev/stdout $(QEMU_ARGS) > "$(CURDIR)/run.out"
 	$(Q)$(REPORT) $(CURDIR)/run.out
 
 # report with existing test log

-- 
2.49.0

Hi Thomas,

On Mon, Jun 09, 2025 at 11:28:58AM +0200, Thomas Weißschuh wrote:
> For the test implementation of the SuperH architecture a second serial
> serial port needs to be used. Unfortunately the currently used 'stdio'
> driver does not support multiple serial ports at the same time.
> 
> Switch to the 'file' driver which does support multiple ports and is
> sufficient for the nolibc-test usecase.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
>  tools/testing/selftests/nolibc/Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> index 22da78a4bfea0274f66abec319d34b3d2a2824ac..238acaa7bb06dcdbcadd9d3190c2de726e1a40b1 100644
> --- a/tools/testing/selftests/nolibc/Makefile
> +++ b/tools/testing/selftests/nolibc/Makefile
> @@ -315,12 +315,12 @@ kernel-standalone: initramfs | defconfig
>  
>  # run the tests after building the kernel
>  run: kernel initramfs.cpio
> -	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
> +	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial file:/dev/stdout $(QEMU_ARGS) > "$(CURDIR)/run.out"
>  	$(Q)$(REPORT) $(CURDIR)/run.out
>  
>  # re-run the tests from an existing kernel
>  rerun:
> -	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
> +	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -initrd initramfs.cpio -serial file:/dev/stdout $(QEMU_ARGS) > "$(CURDIR)/run.out"

I'm cautious every time we touch the -serial output after having faced
issues earlier when trying to use pipes. Here I think it's OK, however,
I'm wondering if "file:$(CURDIR)/run.out" wouldn't be clearer, and also
encourage future changes to stick to a file and avoid piping the output
to a filter command. No strong opinion though.

In any case: Acked-by: Willy Tarreau <w@1wt.eu>

Thanks,
Willy