From patchwork Tue Nov 10 21:52:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Pisa X-Patchwork-Id: 11895471 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CB216697 for ; Tue, 10 Nov 2020 21:58:23 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 591CE20781 for ; Tue, 10 Nov 2020 21:58:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 591CE20781 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cmp.felk.cvut.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:60872 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kcbeg-00010S-8V for patchwork-qemu-devel@patchwork.kernel.org; Tue, 10 Nov 2020 16:58:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34534) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kcbbG-0007im-9u for qemu-devel@nongnu.org; Tue, 10 Nov 2020 16:54:50 -0500 Received: from relay.felk.cvut.cz ([2001:718:2:1611:0:1:0:70]:14116) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kcbbB-0002cS-7N for qemu-devel@nongnu.org; Tue, 10 Nov 2020 16:54:50 -0500 Received: from cmp.felk.cvut.cz (haar.felk.cvut.cz [147.32.84.19]) by relay.felk.cvut.cz (8.15.2/8.15.2) with ESMTP id 0AALrblo095295; Tue, 10 Nov 2020 22:53:37 +0100 (CET) (envelope-from pisa@cmp.felk.cvut.cz) Received: from haar.felk.cvut.cz (localhost [127.0.0.1]) by cmp.felk.cvut.cz (8.14.0/8.12.3/SuSE Linux 0.6) with ESMTP id 0AALrbxs028066; Tue, 10 Nov 2020 22:53:37 +0100 Received: (from pisa@localhost) by haar.felk.cvut.cz (8.14.0/8.13.7/Submit) id 0AALraeB028065; Tue, 10 Nov 2020 22:53:36 +0100 From: Pavel Pisa To: qemu-devel@nongnu.org, Peter Maydell Subject: [PATCH for-5.2 v3 2/4] hw/net/can/ctucan: Avoid unused value in ctucan_send_ready_buffers() Date: Tue, 10 Nov 2020 22:52:48 +0100 Message-Id: <96562ba01919479f7f311050e914419ed3c2f194.1605044619.git.pisa@cmp.felk.cvut.cz> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 X-FELK-MailScanner-Information: X-MailScanner-ID: 0AALrblo095295 X-FELK-MailScanner: Found to be clean X-FELK-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-0.099, required 6, BAYES_00 -0.50, KHOP_HELO_FCRDNS 0.40, SPF_HELO_NONE 0.00, SPF_NONE 0.00) X-FELK-MailScanner-From: pisa@cmp.felk.cvut.cz X-FELK-MailScanner-Watermark: 1605650019.10731@7y1gp9Ofs2U+1lucnbn/Qg Received-SPF: none client-ip=2001:718:2:1611:0:1:0:70; envelope-from=pisa@cmp.felk.cvut.cz; helo=relay.felk.cvut.cz X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/10 16:54:16 X-ACL-Warn: Detected OS = ??? X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pavel Pisa , Jason Wang , Vikram Garhwal , Ondrej Ille , =?utf-8?q?Jan_Charv=C3=A1t?= Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Peter Maydell Coverity points out that in ctucan_send_ready_buffers() we set buff_st_mask = 0xf << (i * 4) inside the loop, but then we never use it before overwriting it later. The only thing we use the mask for is as part of the code that is inserting the new buff_st field into tx_status. That is more comprehensibly written using deposit32(), so do that and drop the mask variable entirely. We also update the buff_st local variable at multiple points during this function, but nothing can ever see these intermediate values, so just drop those, write the final TXT_TOK as a fixed constant value, and collapse the only remaining set/use of buff_st down into an extract32(). Fixes: Coverity CID 1432869 Signed-off-by: Peter Maydell Acked-by: Pavel Pisa Tested-by: Pavel Pisa --- hw/net/can/ctucan_core.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/hw/net/can/ctucan_core.c b/hw/net/can/ctucan_core.c index 8486f429d7..f49c76261c 100644 --- a/hw/net/can/ctucan_core.c +++ b/hw/net/can/ctucan_core.c @@ -240,8 +240,6 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) uint8_t *pf; int buff2tx_idx; uint32_t tx_prio_max; - unsigned int buff_st; - uint32_t buff_st_mask; if (!s->mode_settings.s.ena) { return; @@ -256,10 +254,7 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) for (i = 0; i < CTUCAN_CORE_TXBUF_NUM; i++) { uint32_t prio; - buff_st_mask = 0xf << (i * 4); - buff_st = (s->tx_status.u32 >> (i * 4)) & 0xf; - - if (buff_st != TXT_RDY) { + if (extract32(s->tx_status.u32, i * 4, 4) != TXT_RDY) { continue; } prio = (s->tx_priority.u32 >> (i * 4)) & 0x7; @@ -271,10 +266,7 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) if (buff2tx_idx == -1) { break; } - buff_st_mask = 0xf << (buff2tx_idx * 4); - buff_st = (s->tx_status.u32 >> (buff2tx_idx * 4)) & 0xf; int_stat.u32 = 0; - buff_st = TXT_RDY; pf = s->tx_buffer[buff2tx_idx].data; ctucan_buff2frame(pf, &frame); s->status.s.idle = 0; @@ -283,12 +275,11 @@ static void ctucan_send_ready_buffers(CtuCanCoreState *s) s->status.s.idle = 1; s->status.s.txs = 0; s->tx_fr_ctr.s.tx_fr_ctr_val++; - buff_st = TXT_TOK; int_stat.s.txi = 1; int_stat.s.txbhci = 1; s->int_stat.u32 |= int_stat.u32 & ~s->int_mask.u32; - s->tx_status.u32 = (s->tx_status.u32 & ~buff_st_mask) | - (buff_st << (buff2tx_idx * 4)); + s->tx_status.u32 = deposit32(s->tx_status.u32, + buff2tx_idx * 4, 4, TXT_TOK); } while (1); }