[tip: timers/vdso] selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX

[tip-bot2 for Thomas Weißschuh]

The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     032e871686483ec1bac27ce73e7094692fc76268
Gitweb:        https://git.kernel.org/tip/032e871686483ec1bac27ce73e7094692fc76268
Author:        Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
AuthorDate:    Wed, 26 Feb 2025 12:44:52 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 03 Mar 2025 20:00:13 +01:00

selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX

According to limits.h(2) ULONG_MAX is only guaranteed to expand to an
expression, not a symbolic constant which can be evaluated by the
preprocessor.

Specifically the definition of ULONG_MAX from nolibc can not be evaluated
by the preprocessor. To provide compatibility with nolibc, check with
__SIZEOF_LONG__ instead, with is provided directly by the preprocessor
and therefore always a symbolic constant.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Acked-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-13-28e14e031ed8@xxxxxxxxxxxxx
---
 tools/testing/selftests/vDSO/parse_vdso.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c
index 200c534..902b8f9 100644
--- a/tools/testing/selftests/vDSO/parse_vdso.c
+++ b/tools/testing/selftests/vDSO/parse_vdso.c
@@ -26,7 +26,7 @@
 
 /* And here's the code. */
 #ifndef ELF_BITS
-# if ULONG_MAX > 0xffffffffUL
+# if __SIZEOF_LONG__ >= 8
 #  define ELF_BITS 64
 # else
 #  define ELF_BITS 32