[PATCH] openrisc: define arch-specific version of nop()

From: Brian Masney

Date: Tue Jan 20 2026 - 12:07:54 EST


When compiling a driver written for MIPS on OpenRISC that uses the nop()
function, it fails due to the following error:

drivers/watchdog/pic32-wdt.c: Assembler messages:
drivers/watchdog/pic32-wdt.c:125: Error: unrecognized instruction `nop'

The driver currently uses the generic version of nop() from
include/asm-generic/barrier.h:

#ifndef nop
#define nop() asm volatile ("nop")
#endif

Let's fix this on OpenRISC by defining an architecture-specific version
of nop().

This was tested by performing an allmodconfig openrisc cross compile on
an aarch64 host.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202601180236.BVy480We-lkp@xxxxxxxxx/
Signed-off-by: Brian Masney <bmasney@xxxxxxxxxx>
---
arch/openrisc/include/asm/barrier.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/openrisc/include/asm/barrier.h b/arch/openrisc/include/asm/barrier.h
index 7538294721bed7bc8da3d08f3db89a408091f3f8..8e592c99090235423a9f4c9149da9822918afb13 100644
--- a/arch/openrisc/include/asm/barrier.h
+++ b/arch/openrisc/include/asm/barrier.h
@@ -4,6 +4,8 @@

#define mb() asm volatile ("l.msync" ::: "memory")

+#define nop() asm volatile ("l.nop")
+
#include <asm-generic/barrier.h>

#endif /* __ASM_BARRIER_H */

---
base-commit: d08c85ac8894995d4b0d8fb48d2f6a3e53cd79ab
change-id: 20260120-openrisc-nop-82b7f95dad7f

Best regards,
--
Brian Masney <bmasney@xxxxxxxxxx>