From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 923BB2F38 for ; Mon, 30 May 2022 13:43:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94B68C3411E; Mon, 30 May 2022 13:43:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653918215; bh=LSytcWcRLheFiFAeBtGB+s+5FczB82BvynKoYsa0pVs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bjZ0SVoMjCRUtlCGRLtJG5Q7jSKKJvCSgzxpwcRx7c4dWT4L/LarRhGYG2ogdIrk4 W3bvh2zKvDSPdlmzBwjXD4VzXb2x8zXe6kELe7msrFuqlvUSggTG2hXIi01srcogkS 8TFzLaAP/+ecdAr6xj8IHseZWtCCz9nd7iM4v2lja2W282Ys96GLsLzMfKH5YY6gLT jAl8q7rmXColjwrvkXugA22iKkP+onynkiDMdG4zPhgxOOGtQg3+Mt5vRxNDriStTx n1DeFNCxCwLjRX7kAuJAv94JeOSy1gGNMEhaGI+c8qaRvX+0e9/hHPNTjqMnNui7Sl IJjUN6/p3lFug== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vincent Mailhol , kernel test robot , Nathan Chancellor , Marc Kleine-Budde , Sasha Levin , wg@grandegger.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ndesaulniers@google.com, linux-can@vger.kernel.org, netdev@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 5.15 097/109] can: mcp251xfd: silence clang's -Wunaligned-access warning Date: Mon, 30 May 2022 09:38:13 -0400 Message-Id: <20220530133825.1933431-97-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220530133825.1933431-1-sashal@kernel.org> References: <20220530133825.1933431-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Vincent Mailhol [ Upstream commit 1a6dd9996699889313327be03981716a8337656b ] clang emits a -Wunaligned-access warning on union mcp251xfd_tx_ojb_load_buf. The reason is that field hw_tx_obj (not declared as packed) is being packed right after a 16 bits field inside a packed struct: | union mcp251xfd_tx_obj_load_buf { | struct __packed { | struct mcp251xfd_buf_cmd cmd; | /* ^ 16 bits fields */ | struct mcp251xfd_hw_tx_obj_raw hw_tx_obj; | /* ^ not declared as packed */ | } nocrc; | struct __packed { | struct mcp251xfd_buf_cmd_crc cmd; | struct mcp251xfd_hw_tx_obj_raw hw_tx_obj; | __be16 crc; | } crc; | } ____cacheline_aligned; Starting from LLVM 14, having an unpacked struct nested in a packed struct triggers a warning. c.f. [1]. This is a false positive because the field is always being accessed with the relevant put_unaligned_*() function. Adding __packed to the structure declaration silences the warning. [1] https://github.com/llvm/llvm-project/issues/55520 Link: https://lore.kernel.org/all/20220518114357.55452-1-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Reported-by: kernel test robot Tested-by: Nathan Chancellor # build Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h index 0f322dabaf65..281856eea2ef 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h @@ -433,7 +433,7 @@ struct mcp251xfd_hw_tef_obj { /* The tx_obj_raw version is used in spi async, i.e. without * regmap. We have to take care of endianness ourselves. */ -struct mcp251xfd_hw_tx_obj_raw { +struct __packed mcp251xfd_hw_tx_obj_raw { __le32 id; __le32 flags; u8 data[sizeof_field(struct canfd_frame, data)]; -- 2.35.1