[v2] selftests: vDSO: parse_vdso: Make compatible with nolibc

[PATCH v2 13/16] selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX

Posted by Thomas Weißschuh 9 months, 3 weeks ago

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 no 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@linutronix.de>
---
 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 200c534cc70e2c2381fce3be5c0ebe4cb5675e84..902b8f9984a1f70049d46bcd4f199df24f507dcb 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

-- 
2.48.1

Re: [PATCH v2 13/16] selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX

Posted by Vincenzo Frascino 9 months, 3 weeks ago


On 26/02/2025 11:44, Thomas Weißschuh wrote:
> 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 no 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@linutronix.de>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  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 200c534cc70e2c2381fce3be5c0ebe4cb5675e84..902b8f9984a1f70049d46bcd4f199df24f507dcb 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
> 

-- 
Regards,
Vincenzo

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

Posted by tip-bot2 for Thomas Weißschuh 9 months, 2 weeks ago

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@linutronix.de>
AuthorDate:    Wed, 26 Feb 2025 12:44:52 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
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@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-13-28e14e031ed8@linutronix.de
---
 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