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 0BD3924C692; Mon, 23 Feb 2026 19:55:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771876518; cv=none; b=RuKQxfRIR1kIibNaEskik7kkoCcvSRNnQ3l562mz7Cjwb2U+kavTma3yCKRDL52Fg4t3vLXCNoT7g0SdlJmjNjnYLDXO39Sb9ddma1KN9t6XICB9kDi7gabFHfLkyKOABqo4F9tIS4PUPParxyoBDbqCPgbOxqpqBMH5vEwh+WM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771876518; c=relaxed/simple; bh=EzRTpn7SStmQR6adoeUhLcxNBw1WrKVexjwB3Z8Jb2A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tiFhB2S1KjYpEXGCCHe9XoDBkFyPeLohDTnMaPIgHCr0jmorIlp1IgNty6TAarwZU2jDYmzJ/t6w+yRMv3Ous3FsT8w3mIQAUqtWmu4hZFi9ROtztSUFFAZpbudk4EnNfOtyIUAzFg/cPUO45HSDtSMN3px1qXtv6NjCsv0Njls= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mLgQYtzj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mLgQYtzj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AA70C19421; Mon, 23 Feb 2026 19:55:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771876517; bh=EzRTpn7SStmQR6adoeUhLcxNBw1WrKVexjwB3Z8Jb2A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mLgQYtzjl7m489aHT5PFS4KCwD++7m9HmbTt4vvtX+sCykeMxSZ64jrtyvg7sbNKq KX+qpL3vv0E39vVIGWtsmYHjtSTzPKbCptWoe5NxbNF4RUWbpEka3BftzEwWXvhlYd 9lgHPWTH0ny73tjL5YusnLP3K2sgpu6f3UVbgPxSOhpuYsKWQaFvlPLk4edktO+BQi tWVDy0vIQM1iEzPfPtgNC1/L9XuYe4Qf5F69rXZEEOs89jNdZgQ+8J6XhopTR7mPq1 c7DVymskANhTAza7xuDVMc/ebN+d4TsktX89VLMPNqHsvy/V7wLaBcUKXGif2tl94l SL/VSv5CcDjQw== Message-ID: Date: Mon, 23 Feb 2026 20:55:14 +0100 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] firmware: exynos-acpm: Drop fake 'const' on handle pointer To: Krzysztof Kozlowski , Tudor Ambarus , Alim Akhtar , linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org References: <20260223193416.532231-2-krzysztof.kozlowski@oss.qualcomm.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/02/2026 20:34, Krzysztof Kozlowski wrote: > All the functions operating on the 'handle' pointer are claiming it is a > pointer to const thus they should not modify the handle. In fact that's > a false statement, because first thing these functions do is drop the > cast to const with container_of: > > struct acpm_info *acpm = handle_to_acpm_info(handle); > > And with such cast the handle is easily writable with simple: > > acpm->handle.ops.pmic_ops.read_reg = NULL; > > The code is not correct logically, either, because functions like > acpm_get_by_node() and acpm_handle_put() are meant to modify the handle > reference counting, thus they must modify the handle. They could not > work with handle being pointer to const. > > The code does not have actual visible bug, but incorrect 'const' > annotations could lead to incorrect compiler decisions. > > Fixes: a88927b534ba ("firmware: add Exynos ACPM protocol driver") > Cc: > Signed-off-by: Krzysztof Kozlowski > > --- > > I will have more patches for more drivers like TI, ARM SCMI... > --- > drivers/firmware/samsung/exynos-acpm-dvfs.c | 4 +- > drivers/firmware/samsung/exynos-acpm-dvfs.h | 4 +- > drivers/firmware/samsung/exynos-acpm-pmic.c | 10 ++--- > drivers/firmware/samsung/exynos-acpm-pmic.h | 10 ++--- > drivers/firmware/samsung/exynos-acpm.c | 16 ++++---- > drivers/firmware/samsung/exynos-acpm.h | 2 +- > .../firmware/samsung/exynos-acpm-protocol.h | 40 ++++++++----------- > 7 files changed, 41 insertions(+), 45 deletions(-) I forgot about clocks, so there will be a v2. Best regards, Krzysztof