On 9/14/2026 4:55 PM, Ilya Leoshkevich wrote: > > > On 9/14/26 18:07, Alex Bennée wrote: >> Daniel P. Berrangé <[email protected]> writes: >> >> (trimed cc list, add Ilya) >> >>> On Sun, Sep 13, 2026 at 10:08:52PM -0700, Pierrick Bouvier wrote: >>>> On 9/10/26 11:14 AM, Alex Bennée wrote: >>>>> From: Daniel P. Berrangé <[email protected]> >>>>> >>>>> When it finds a cross compiler, tests/tcg/meson.build tries >>>>> building test_cc.c to validate that the compiler works. This >>>>> includes "stdint.h" as a witness for working C library, however, >>>>> that is not a good choice as it can be provided by the toolchain >>>>> alone: >>>>> >>>>> $ rpm -ql gcc-s390x-linux-gnu | grep /stdint.h >>>>> /usr/lib/gcc/s390x-linux-gnu/16/include/stdint.h >>>>> >>>>> As a result, if you install the s390x GCC cross compiler, but >>>>> not any C library, meson decides to use the host compiler instead >>>>> of the container: >>>>> >>>>> cc for aarch64-softmmu : aarch64-linux-gnu-gcc (from >>>>> 'debian-all-test-cross' container) >>>>> cc for loongarch64-softmmu : loongarch64-unknown-linux- >>>>> gnu-gcc (from 'debian-loongarch-cross' container) >>>>> cc for riscv64-softmmu : riscv64-linux-gnu-gcc (from >>>>> 'debian-all-test-cross' container) >>>>> cc for s390x-softmmu : s390x-linux-gnu-gcc >>>>> cc for x86_64-softmmu : x86_64-linux-gnu-gcc (from >>>>> 'debian-amd64-cross' container) >>>>> >>>>> Eventually this results in failure to run 'make check': >>>>> >>>>> [33/40] Generating tests/tcg/s390x-softmmu-hello with a custom command >>>>> FAILED: [code=1] tests/tcg/s390x-softmmu-hello.test >>>>> /usr/bin/s390x-linux-gnu-gcc /home/berrange/src/virt/qemu/tests/ >>>>> tcg/multiarch/system/hello.c -o tests/tcg/s390x-softmmu-hello.test >>>>> -static -MMD -MF tests/tcg/s390x-softmmu-hello.d -Wall -Werror -O0 >>>>> -g -fno-strict-aliasing -nostdlib -ffreestanding -Wa,--noexecstack >>>>> -I /home/berrange/src/virt/qemu/tests/tcg/s390x/system/../../ >>>>> minilib /home/berrange/src/virt/qemu/tests/tcg/s390x/system/../../ >>>>> minilib/printf.c -I /home/berrange/src/virt/qemu/include/hw/s390x/ >>>>> ipl -march=z13 ../tests/tcg/s390x/system/../head64.S ../tests/tcg/ >>>>> s390x/system/../console.c >>>>> In file included from ../tests/tcg/s390x/system/../console.c:8: >>>>> ../tests/tcg/s390x/system/../../../../pc-bios/s390-ccw/ >>>>> sclp.c:11:10: fatal error: string.h: No such file or directory >>>>> 11 | #include <string.h> >>>>> | ^~~~~~~~~~ >>>>> compilation terminated. >>>>> >>>>> Adding more include files to the test program ensures the >>>>> meson probe makes a better decision. >>>>> >>>>> Fixes: e5d084d622b1 (tests/tcg/meson.build: check host cross cc is >>>>> working) >>>>> Signed-off-by: Daniel P. Berrangé <[email protected]> >>>>> Message-ID: <[email protected]> >>>>> Signed-off-by: Alex Bennée <[email protected]> >>>>> --- >>>>> tests/tcg/test_cc.c | 6 +++++- >>>>> 1 file changed, 5 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/tests/tcg/test_cc.c b/tests/tcg/test_cc.c >>>>> index d3614a01fe6..fafee055b40 100644 >>>>> --- a/tests/tcg/test_cc.c >>>>> +++ b/tests/tcg/test_cc.c >>>>> @@ -1,7 +1,11 @@ >>>>> /* SPDX-License-Identifier: GPL-2.0-or-later */ >>>>> -/* Include a standard header to make sure cross compiler provides >>>>> them */ >>>>> +/* Use some standard headers to ensure the cross compiler provides >>>>> them */ >>>>> #include <stdint.h> >>>>> +#include <string.h> >>>>> +#include <stdbool.h> >>>>> +#include <stddef.h> >>>>> +#include <stdio.h> >>>>> int main(void) >>>>> { >>>> >>>> Ideally, we should do separate tests for system vs user tests. >>>> System ones are always compiled with -ffreestanding, while user ones >>>> should >>>> provide a C library. >>>> >>>> From this standard: >>>> >>>> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2338r3.html >>>> ``` >>>> A freestanding C implementation is required to provide the entirety >>>> of the >>>> following headers: >>>> >>>> <float.h> >>>> <iso646.h> >>>> <limits.h> >>>> <stdalign.h> >>>> <stdarg.h> >>>> <stdbool.h> >>>> <stddef.h> >>>> <stdint.h> >>>> <stdnoreturn.h> >>>> Most of <string.h> is required (strdup, strndup, strcoll, strxfrm, and >>>> strerror are excluded). This includes strtok, which requires global >>>> data. >>>> ``` >>>> >>>> Maybe for now we can just remove stdio.h from current patch, as it's >>>> not >>>> supposed to be provided in a freestanding environment. >>> >>> A huge number of files under tests/tcg/ have a #include <stdio.h> >>> currently. >> >> They are all *-user mode tests though, which do need a proper libc. >> >>> >>> In the example build failure in the commit message, we have >>> >>> tests/tcg/s390x/system/../console.c >>> >>> which does >>> >>> #include "../../../pc-bios/s390-ccw/sclp.c" >>> >>> and sclp.c has >>> >>> #include "s390-ccw.h" >>> >>> and that header has: >>> >>> #include <stdbool.h> >>> #include <stddef.h> >>> #include <stdint.h> >>> #include <stdio.h> >>> >>> hence the 4 headers I added to the meson check. >>> >>> So AFAICT, our code is expecting stdio.h to be provided in a >>> -ffreestanding build. Have we got a more fundamental mistake >>> wrt our use of -ffreestanding, such that it is relying on >>> unintended functionality ? >> >> They shouldn't - but s390x seems to be doing something funky here. Ilya >> can you explain what s390x is trying to do here? > > s390x used to use SLOF headers before the meson rework. > I remember that Pierrick mentioned there were issues with checking out > the SLOF submodule, but it seems to work for me. > So I've posted my version of the fix [1], please take a look. >
There is no problem to checkout SLOF submodule, but I simply thought it would be cleaner to not have tests transitively trigger a git submodule update. If it's not a problem for anyone else except me, I'm fine with seeing it reintroduced (see further comments on your patch). With the right test Daniel added here, we should skip host compiler, and rely on cross containers instead, which provide a libc. > [1] https://lore.kernel.org/qemu-devel/20260914235113.272992-1- > [email protected]/ > >> >>> >>> With regards, >>> Daniel >> > Thanks, Pierrick
