From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B704E511E8C; Fri, 11 Sep 2026 19:28:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=5.75.144.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789154909; cv=none; b=NvZ6UAQjAuG7wW3pqUSKISxp8FgKfdmGD5KOJyN8TO2JMXDqtHWHQWhy/XzU4aLx9fAbkgij6lGIgO0cmyvwN/TkUu+YzIQ2W9+MsGs18HadonPrStELnxPtswy8E+ivZ8qnVY78eWC4PU30ht+ojYj/WbPMUWeYr34JFBWDGn8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789154909; c=relaxed/simple; bh=hFNZfjG7awykZCdqNUHs3x/U/7ivwWB0Evtzikm7ItA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ly6ZI2qNy2NkNU1B9pq64v656uyzia0yMYRr3BkPbZG8DoWslnkia23kksrFo394542kKyaV/tta3E86DeByeMl01P5lWmNLi5EmjmKuUGZW9IdkI0UTA6jN/BYL4bvpmWYRqELIOJl53boA2uANnQfb9tJDIvYyUyCuxWn5w3Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org; spf=pass smtp.helo=mail.mainlining.org; arc=none smtp.client-ip=5.75.144.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.helo=mail.mainlining.org From: Bradley Morgan To: "Paul E. McKenney" Cc: frederic@kernel.org, neeraj.upadhyay@kernel.org, boqun@kernel.org, joelagnelf@nvidia.com, rcu@vger.kernel.org, "Andrew Morton" , "Arnd Bergmann" , linux-arch@vger.kernel.org, "Vineet Gupta" , linux-snps-arc@lists.infradead.org, "Russell King" , linux-arm-kernel@lists.infradead.org, "Guo Ren" , linux-csky@vger.kernel.org, "Yoshinori Sato" , "Rich Felker" , "John Paul Adrian Glaubitz" , linux-sh@vger.kernel.org, "Chris Zankel" , "Max Filippov" , linux-kernel@vger.kernel.org, brads@mainlining.org Subject: [PATCH 5/6] sh: Emulate two-byte cmpxchg Date: Fri, 11 Sep 2026 19:25:38 +0000 Message-ID: <20260911192540.20983-6-brads@mainlining.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260911192540.20983-1-brads@mainlining.org> References: <20260911192540.20983-1-brads@mainlining.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit SH has no byte or halfword atomic memory operations, so the __cmpxchg() switch routes case 1 through cmpxchg_emu_u8() and lets case 2 fall through to __cmpxchg_called_with_bad_pointer(), which is declared but never defined, so a two-byte cmpxchg() fails at link time. Route case 2 through the new cmpxchg_emu_u16(). Signed-off-by: Bradley Morgan --- arch/sh/include/asm/cmpxchg.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h index 1e5dc5ccf7bf..477d3025a441 100644 --- a/arch/sh/include/asm/cmpxchg.h +++ b/arch/sh/include/asm/cmpxchg.h @@ -59,6 +59,8 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old, switch (size) { case 1: return cmpxchg_emu_u8(ptr, old, new); + case 2: + return cmpxchg_emu_u16(ptr, old, new); case 4: return __cmpxchg_u32(ptr, old, new); } -- 2.47.3