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.
[1]
https://lore.kernel.org/qemu-devel/[email protected]/
With regards,
Daniel
