On 25/06/2025 at 08:19, Sean Christopherson wrote:
> Rename is_signed_type() to is_signed_var() to avoid colliding with a macro
> of the same name defined by linux/overflow.h. Note, overflow.h's version
> takes a type as the input, whereas the harness's version takes a variable!
>
> This fixes warnings (and presumably potential test failures) in tests
> that utilize the selftests harness and happen to (indirectly) include
> overflow.h.
>
> In file included from tools/include/linux/bits.h:34,
> from tools/include/linux/bitops.h:14,
> from tools/include/linux/hashtable.h:13,
> from include/kvm_util.h:11,
> from x86/userspace_msr_exit_test.c:11:
> tools/include/linux/overflow.h:31:9: error: "is_signed_type" redefined
> [-Werror]
> 31 | #define is_signed_type(type) (((type)(-1)) < (type)1)
> | ^~~~~~~~~~~~~~
> In file included from include/kvm_test_harness.h:11,
> from x86/userspace_msr_exit_test.c:9:
> ../kselftest_harness.h:754:9: note: this is the location of the previous
> definition
> 754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) <
> (__typeof__(var))1))
> | ^~~~~~~~~~~~~~
>
> Opportunistically use is_signed_type() to implement is_signed_var() so
> that the relationship and differences are obvious.
>
> Fixes: fc92099902fb ("tools headers: Synchronize linux/bits.h with the kernel
> sources")
> Cc: Vincent Mailhol <mailhol.vinc...@wanadoo.fr>
> Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
> Signed-off-by: Sean Christopherson <sea...@google.com>
> ---
>
> This is probably compile-tested only, I don't think any of the KVM selftests
> utilize the harness's EXPECT macros.
>
> tools/testing/selftests/kselftest_harness.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/kselftest_harness.h
> b/tools/testing/selftests/kselftest_harness.h
> index 2925e47db995..f3e7a46345db 100644
> --- a/tools/testing/selftests/kselftest_harness.h
> +++ b/tools/testing/selftests/kselftest_harness.h
> @@ -56,6 +56,7 @@
> #include <asm/types.h>
> #include <ctype.h>
> #include <errno.h>
> +#include <linux/overflow.h>
> #include <linux/unistd.h>
> #include <poll.h>
> #include <stdbool.h>
> @@ -751,7 +752,7 @@
> for (; _metadata->trigger; _metadata->trigger = \
> __bail(_assert, _metadata))
>
> -#define is_signed_type(var) (!!(((__typeof__(var))(-1)) <
> (__typeof__(var))1))
> +#define is_signed_var(var) is_signed_type(__typeof__(var))
It would potentially make sense to add the is_signed_var() to overflow.h. I see
a couple places doing some is_signed_type(typeof(x)):
$ git grep "is_signed_type(typeof" | wc -l
5
And I can imagine this number growing in the future.
But this is by no way a reason strong enough to block this patch. It is just a
random idea I am sharing here.
So that said:
Reviewed-by: Vincent Mailhol <mailhol.vinc...@wanadoo.fr>
> #define __EXPECT(_expected, _expected_str, _seen, _seen_str, _t, _assert) do
> { \
> /* Avoid multiple evaluation of the cases */ \
> @@ -759,7 +760,7 @@
> __typeof__(_seen) __seen = (_seen); \
> if (!(__exp _t __seen)) { \
> /* Report with actual signedness to avoid weird output. */ \
> - switch (is_signed_type(__exp) * 2 + is_signed_type(__seen)) { \
> + switch (is_signed_var(__exp) * 2 + is_signed_var(__seen)) { \
> case 0: { \
> uintmax_t __exp_print = (uintmax_t)__exp; \
> uintmax_t __seen_print = (uintmax_t)__seen; \
>
> base-commit: 78f4e737a53e1163ded2687a922fce138aee73f5
Yours sincerely,
Vincent Mailhol
