From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 15 Aug 2024 07:54:29 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1seTRN-009mGE-25 for lore@lore.pengutronix.de; Thu, 15 Aug 2024 07:54:29 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1seTRM-0007za-Ur for lore@pengutronix.de; Thu, 15 Aug 2024 07:54:29 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=y6WjAVqD++KCLn5H+kh0aHBslFAUG/hpbLAE6jPNQtY=; b=zAJheMFUgo7YxL1q7y6X4C09zK e1Nl2j4aGIDac1mgQTo4nVHqmqh6bXBtXgMDsfr1a5V4dz7n35nDu9TrtogKJzo//5PkvgUd3cqhS P6IeNLvQ7ittJDcxBvW9VOt6yjr4VbInvDoIcy/OzyeRZWm2/OqGY2Bm3ztjcOisZ6QaAakUVzWcR s2mS8Uw9WUkTo7rddMe9wuOf6gl90v6dsNquUU8IR3Zq3mVXaIdpFIrKzzLkXq5Clh5HExdD0f8G9 L8NL1RIGNaP4pUkn1R4xEIQOjP+fGASTHU2fnNBHThlDNPtGnOXX42HSe3aRRRQT0GA3nrqWxDkFO Izovc2rw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1seTQa-000000097gu-44kh; Thu, 15 Aug 2024 05:53:40 +0000 Received: from smtp.cesky-hosting.cz ([2001:67c:e94:0:1:5bef:c8ee:1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1seTQW-000000097gA-064i for barebox@lists.infradead.org; Thu, 15 Aug 2024 05:53:38 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=elrest.cz; s=rampa2-202408; t=1723701195; bh=MDLvx2CfxrtT8H72hCARj4P8f9z9Fwpdd8V9ykzeW4g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DG9uLVChJpHIp2J5Sx61BTsMUJEt+Ew0ZWpnYye66HQTjXxccIfArR2UTEYx0Kpyq T5/omzoudT1eaWct4DQwQvcv6MvXE3tBOpst/GUjgP7oeUUGBSDRDz8yXbJqOlgLD1 FS1KDgGqsx601UaNBcn/WrYC1RX8Y2tdryXTkojAv19///IZ/MQt2cP+4wh4NvzmdX qRqiKyiGuaK1xYbtrMsy1xrPFRqJEV59DK3Rp/PqP+VK3DCjmLKNNlHUqrYj24lTb5 EZCyRXzWO3t6DjBUVxhADZDhPnCyAN9Lx8V8wKxCjWJ7HarQv7GEgh3GqhBWIVM6u7 USNk/zQ/DB3tg== X-Virus-Scanned: Debian amavis at smtp.cesky-hosting.cz X-Thin-Conversation: seen Received: from debian (unknown [185.63.98.16]) (Authenticated sender: tomas.marek@elrest.cz) by smtp.cesky-hosting.cz (Postfix) with ESMTPSA id 4WkvRs2GqHzSV; Thu, 15 Aug 2024 07:53:12 +0200 (CEST) Date: Thu, 15 Aug 2024 07:53:10 +0200 From: Tomas Marek To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: References: <20240814092424.39878-1-a.fatoum@pengutronix.de> <20240814092424.39878-5-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240814092424.39878-5-a.fatoum@pengutronix.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240814_225336_528489_6EECFFFE X-CRM114-Status: GOOD ( 17.29 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 5/6] i2c: efi: avoid 64-bit division X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hello Ahmad, Thanks for maintenance of the Barebox EFI. On Wed, Aug 14, 2024 at 11:24:23AM +0200, Ahmad Fatoum wrote: > I2C message length is 16 bit, so doing a 64-bit division is overkill. > Let's remove the cast and just rely on the usual integer promotion > to 32-bit. > > Cc: Tomas Marek > Signed-off-by: Ahmad Fatoum > --- > drivers/i2c/busses/i2c-efi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-efi.c b/drivers/i2c/busses/i2c-efi.c > index 5f6cc0eed28e..a666a28fab51 100644 > --- a/drivers/i2c/busses/i2c-efi.c > +++ b/drivers/i2c/busses/i2c-efi.c > @@ -114,7 +114,7 @@ static unsigned int efi_i2c_msg_op_cnt(const struct efi_i2c_priv *i2c_priv, > > max_len = efi_i2c_max_len(i2c_priv, msg); > > - return ((u64)msg->len + max_len - 1) / max_len; > + return (msg->len + max_len - 1) / max_len; The issue here is that max_len, which represents the MaximumReceiveBytes or MaximumTransmitBytes in EFI I2C capabilities, is 32-bit. In some EFI implementations (including the one I use), the EFI I2C MaximumReceiveBytes and MaximumTransmitBytes are set to the maximum value (0xFFFFFFFF). This causes msg->len + max_len - 1 to overflow, leading to an incorrect number of returned operations. To address this, the msg->len is extended to 64 bits. Best regards Tomas > } > > static unsigned int efi_i2c_req_op_cnt( > -- > 2.39.2 >