linux-kernel - [PATCH v2 06/13] tools/nolibc/gettimeofday: avoid libgcc 64-bit divisions

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Message-Id: <20251122-nolibc-uapi-types-v2-6-b814a43654f5@weissschuh.net>
Date: Sat, 22 Nov 2025 17:59:12 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Willy Tarreau <w@....eu>, Shuah Khan <shuah@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v2 06/13] tools/nolibc/gettimeofday: avoid libgcc 64-bit
 divisions

timespec::tv_nsec is going to be 64-bit wide even on 32-bit
architectures. As not all architectures support 64-bit division
instructions, calls to libgcc (__divdi3()) may be emitted by the
compiler which are not provided by nolibc.

As tv_nsec is guaranteed to always fit into an uint32_t, perform a
32-bit division instead.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
Reviewed-by: Arnd Bergmann <arnd@...db.de>
Acked-by: Willy Tarreau <w@....eu>
---
 tools/include/nolibc/sys/time.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/include/nolibc/sys/time.h b/tools/include/nolibc/sys/time.h
index 171187836e6d..afdb7e326df1 100644
--- a/tools/include/nolibc/sys/time.h
+++ b/tools/include/nolibc/sys/time.h
@@ -30,7 +30,7 @@ int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
 	ret = sys_clock_gettime(CLOCK_REALTIME, &tp);
 	if (!ret && tv) {
 		tv->tv_sec = tp.tv_sec;
-		tv->tv_usec = tp.tv_nsec / 1000;
+		tv->tv_usec = (uint32_t)tp.tv_nsec / 1000;
 	}
 
 	return ret;

-- 
2.52.0