[PATCH v3] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[PATCH v3] selftests: futex: define SYS_futex on 32-bit architectures with 64-bit time_t

[Ben Zong-You Xie]

From: Cynthia Huang <cynthia@andestech.com>

Linux kernel does not provide sys_futex() on some 32-bit architectures
that do not support 32-bit time representations, such as riscv32.
As a result, glibc cannot define SYS_futex, causing compilation failures
in tests that rely on this syscall. Define SYS_futex as SYS_futex_time64
in such cases 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 v2:
  - Refine the commit message suggested by tglx
  - Attribute the authorship to Cynthia
  - Add the Reviewed-by tag from Muhammad

v2 : https://lore.kernel.org/all/20250627090812.937939-1-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