[PATCH v2] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[PATCH v2] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[Ben Zong-You Xie]

glibc does not define SYS_futex for 32-bit architectures using 64-bit
time_t e.g. riscv32, therefore this test fails to compile since it does not
find SYS_futex in C library headers. Define SYS_futex as SYS_futex_time64
in this situation to ensure successful compilation and compatibility.

Signed-off-by: Cynthia Huang <cynthia@andestech.com>
Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
---
Changes since v1:
  - Fix the SOB chain

v1 : https://lore.kernel.org/all/20250527093536.3646143-1-ben717@andestech.com/
---
 tools/testing/selftests/futex/include/futextest.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/testing/selftests/futex/include/futextest.h b/tools/testing/selftests/futex/include/futextest.h
index ddbcfc9b7bac..7a5fd1d5355e 100644
--- a/tools/testing/selftests/futex/include/futextest.h
+++ b/tools/testing/selftests/futex/include/futextest.h
@@ -47,6 +47,17 @@ typedef volatile u_int32_t futex_t;
 					 FUTEX_PRIVATE_FLAG)
 #endif

+/*
+ * SYS_futex is expected from system C library, in glibc some 32-bit
+ * architectures (e.g. RV32) are using 64-bit time_t, therefore it doesn't have
+ * SYS_futex defined but just SYS_futex_time64. Define SYS_futex as
+ * SYS_futex_time64 in this situation to ensure the compilation and the
+ * compatibility.
+ */
+#if !defined(SYS_futex) && defined(SYS_futex_time64)
+#define SYS_futex SYS_futex_time64
+#endif
+
 /**
  * futex() - SYS_futex syscall wrapper
  * @uaddr:	address of first futex
--
2.34.1

Re: [PATCH v2] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[Muhammad Usama Anjum]

On 6/27/25 2:08 PM, Ben Zong-You Xie wrote:
> glibc does not define SYS_futex for 32-bit architectures using 64-bit
> time_t e.g. riscv32, therefore this test fails to compile since it does not
> find SYS_futex in C library headers. Define SYS_futex as SYS_futex_time64
> in this situation to ensure successful compilation and compatibility.
> 
> Signed-off-by: Cynthia Huang <cynthia@andestech.com>
> Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>

> ---
> Changes since v1:
>   - Fix the SOB chain
> 
> v1 : https://lore.kernel.org/all/20250527093536.3646143-1-ben717@andestech.com/
> ---
>  tools/testing/selftests/futex/include/futextest.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/tools/testing/selftests/futex/include/futextest.h b/tools/testing/selftests/futex/include/futextest.h
> index ddbcfc9b7bac..7a5fd1d5355e 100644
> --- a/tools/testing/selftests/futex/include/futextest.h
> +++ b/tools/testing/selftests/futex/include/futextest.h
> @@ -47,6 +47,17 @@ typedef volatile u_int32_t futex_t;
>  					 FUTEX_PRIVATE_FLAG)
>  #endif
> 
> +/*
> + * SYS_futex is expected from system C library, in glibc some 32-bit
> + * architectures (e.g. RV32) are using 64-bit time_t, therefore it doesn't have
> + * SYS_futex defined but just SYS_futex_time64. Define SYS_futex as
> + * SYS_futex_time64 in this situation to ensure the compilation and the
> + * compatibility.
> + */
> +#if !defined(SYS_futex) && defined(SYS_futex_time64)
> +#define SYS_futex SYS_futex_time64
> +#endif
> +
>  /**
>   * futex() - SYS_futex syscall wrapper
>   * @uaddr:	address of first futex
> --
> 2.34.1

Re: [PATCH v2] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[Thomas Gleixner]

On Fri, Jun 27 2025 at 17:08, Ben Zong-You Xie wrote:

> glibc does not define SYS_futex for 32-bit architectures using 64-bit

Kinda. The kernel does not provide sys_futex() on 32-bit architectures,
which do not support 32-bit time representations. As a consequence glibc
obviously cannot define SYS_futex either.

> time_t e.g. riscv32, therefore this test fails to compile since it does not
> find SYS_futex in C library headers. Define SYS_futex as SYS_futex_time64
> in this situation to ensure successful compilation and compatibility.
>
> Signed-off-by: Cynthia Huang <cynthia@andestech.com>
> Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
> ---
> Changes since v1:
>   - Fix the SOB chain

Mostly.

If Cynthia authored the patch, then this still lacks a 'From: Cynthia...'
at the top of the change log so she can be identified as the
author. Otherwise tooling will attribute autorship to you.

Thanks,

        tglx