From patchwork Wed Nov 2 17:22:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 13028683 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DD8CC433FE for ; Wed, 2 Nov 2022 17:22:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230376AbiKBRWk (ORCPT ); Wed, 2 Nov 2022 13:22:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230348AbiKBRWk (ORCPT ); Wed, 2 Nov 2022 13:22:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8325A26139; Wed, 2 Nov 2022 10:22:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2899C61A32; Wed, 2 Nov 2022 17:22:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7984C433D7; Wed, 2 Nov 2022 17:22:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667409758; bh=VOPxx1E3nzgzSX4/T9iDwxmKIdfR07u/REHayG82ioQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZtR38H8afcyKcjaRxplQiaodCrL6U01+2ictVzJ4eHQLw6h4wKkBdIU9rNti2ps1Y TXphRcqiH+UQYvmt9VNEY0vEPDdvb+86uKZpXSicZgUZoBJN1FaZFT0S89R9Td4ev8 +tDz9GkFAhGFTE30cokMoULtgCD+J8197M/VdNPkFqCWjR2HiULLjuLIqd/3/bN7nT SIXXwSuZvJ4SdT/WVIzQoLCIUnlnAR4uo1u1B+EZx7rXmqVpz7E+n8DlbLEZZPucyw VmAV9DBVfsAvOuR40tskWxq/YywPMtvI93YZQAMuIh2QLOy6ZCBhehYTMcbdv8shMR C7srL5Lm0GQ9g== From: Nathan Chancellor To: William Breathitt Gray Cc: linux-iio@vger.kernel.org, Nick Desaulniers , Tom Rix , Kees Cook , Sami Tolvanen , llvm@lists.linux.dev, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Nathan Chancellor , Fabrice Gasnier , linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com Subject: [PATCH 2/4] counter: stm32-timer-cnt: Adjust final parameter type of stm32_count_direction_read() Date: Wed, 2 Nov 2022 10:22:15 -0700 Message-Id: <20221102172217.2860740-2-nathan@kernel.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221102172217.2860740-1-nathan@kernel.org> References: <20221102172217.2860740-1-nathan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/counter/stm32-timer-cnt.c:220:2: error: incompatible function pointer types initializing 'int (*)(struct counter_device *, struct counter_count *, u32 *)' (aka 'int (*)(struct counter_device *, struct counter_count *, unsigned int *)') with an expression of type 'int (struct counter_device *, struct counter_count *, enum counter_count_direction *)' [-Werror,-Wincompatible-function-pointer-types-strict] COUNTER_COMP_DIRECTION(stm32_count_direction_read), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/linux/counter.h:596:20: note: expanded from macro 'COUNTER_COMP_DIRECTION' .count_u32_read = (_read), \ ^~~~~~~ 1 error generated ->count_u32_read() in 'struct counter_comp' expects a return type of 'u32 *', not 'enum counter_count_direction *'. Adjust the final parameter type of stm32_count_direction_read() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Reported-by: Sami Tolvanen Signed-off-by: Nathan Chancellor --- Cc: Fabrice Gasnier Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com --- drivers/counter/stm32-timer-cnt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c index ece55113ba85..4062296f4bd4 100644 --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -137,7 +137,7 @@ static int stm32_count_function_write(struct counter_device *counter, static int stm32_count_direction_read(struct counter_device *counter, struct counter_count *count, - enum counter_count_direction *direction) + u32 *direction) { struct stm32_timer_cnt *const priv = counter_priv(counter); u32 cr1;