From patchwork Fri Jul 28 00:02:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 127264 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp98072vqg; Thu, 27 Jul 2023 17:30:11 -0700 (PDT) X-Google-Smtp-Source: APBJJlFo4FH3x7b6JrF6ni4GvkoypJlsce/hhzbvLdh7Vekaj5fyLfEMUZIlq3UNy8sG+BxDpmnE X-Received: by 2002:a17:906:cc4b:b0:993:f2b4:13c9 with SMTP id mm11-20020a170906cc4b00b00993f2b413c9mr533571ejb.21.1690504211258; Thu, 27 Jul 2023 17:30:11 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690504211; cv=none; d=google.com; s=arc-20160816; b=Br4HWhMdBs6Ke2eYT60zz47X2G/gCCV/w9Ce3MDziQHczLIQ3ZVofnqNtrD3MeIbZA FlGzrZ+jzyFMf467MJ0RIUtKaRkcchqYcOHJIiLpe78ncCtlIhYZSlNvZXJJ/FHHOfdf McTxZAvr5BDypPkA1cFrT6TxS0pkExg3dFf1U8A7qBD2N2gEyS1yMfZ/DhtkhvqdXD2Z V5D94Au6Ieei/yPLlWqFmTFU81Vhx9wLOEokwIhB1CVCJ1/x2ftikA/0+zWDdwLM1Osz cMlNaXQ4vDc/5fQzpnjz37OratVw3C/lSK8/jwaJoOIsgNBvoeNkqDFZYIyAdnnqLMQW mvPw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:dkim-signature :dkim-signature:from; bh=xb4IARB7ZGs0NFGdahNKOcVuwqCsWQdgRW9ky2NkqP0=; fh=I/6bvJz6sWq8p1xoNUgGjc7lme65GQ/wcdq821dg0a8=; b=wU4p6iOcKrfcmAcIU5TotcbaXqHDpd4gy8LKV0dMlVPd/7ZaGVAMmVZKqYpHYuqhS3 kMA/URb1ZOSrT48VZXVOe2jIkyn1ft3GnDvQTUdYWUB8vvLAiKG7y5V96a/QmuGQ0OgL /+08OB5szoMxLDppybXhfx0BRpBDQ1RNnxNell8wl1E0V9FkJaAT1/RPn92JOh9ImBVD geOMfCvF/Ia/Kz9wYTWZW76YakUiwinH+bhJb97QpPVlPFdYqh8ajVM+BTCfj2is+63C zMcg3Mp2Vf+tDr+V0a+GwXoczWG0d8WJo//vryLs0T2mcLI21n8+lo1vk45SHvB4hNXe zQLg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=bHC60CvV; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=OClN8Ozq; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id ga6-20020a170906b84600b00989027eb30bsi1929120ejb.610.2023.07.27.17.29.46; Thu, 27 Jul 2023 17:30:11 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=bHC60CvV; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=OClN8Ozq; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231697AbjG1ADA (ORCPT + 99 others); Thu, 27 Jul 2023 20:03:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231481AbjG1ACn (ORCPT ); Thu, 27 Jul 2023 20:02:43 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 025E0170D for ; Thu, 27 Jul 2023 17:02:42 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1690502559; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xb4IARB7ZGs0NFGdahNKOcVuwqCsWQdgRW9ky2NkqP0=; b=bHC60CvVn0k5V/Ob2wGVruqaoijuC5OhwuGq8OdO28M1v7kmYBNC5Pcqlj112Tv329px04 xoOv0JbDAZi0d03qVzIOkCpF4WQqlZHC5grMzu3eSIEdETyqjHzI4FFpNF4tAECymfMoU/ 1prM90FTfK0afeyH9Y3/MWGPlJWUQ8RpEzLBEje2JR+Dgnci+X/hzJ6zRCI7/1JSuJ7MnM gQS9e8ch2R/Fu0sDtea01twbCChPWz4ci6k472ezTOlD3l01I+CjNir1j30oIDTNLEtWJe N8uEgfZ9p79D7fCuV51NoJidOWaApXHLw0GmUz/EpfFxkjiqifa9L1ptEHhEbA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1690502559; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xb4IARB7ZGs0NFGdahNKOcVuwqCsWQdgRW9ky2NkqP0=; b=OClN8Ozq+PUpq9KrNWc9iSN08LxWbFx7BcujZAphNTRhSaICw0IwD2aaHDjeSPsnVeuht6 4AgtmvM4HAAqv/CA== To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Greg Kroah-Hartman Subject: [PATCH printk v2 8/8] printk: nbcon: Add functions for drivers to mark unsafe regions Date: Fri, 28 Jul 2023 02:08:33 +0206 Message-Id: <20230728000233.50887-9-john.ogness@linutronix.de> In-Reply-To: <20230728000233.50887-1-john.ogness@linutronix.de> References: <20230728000233.50887-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,INVALID_DATE_TZ_ABSURD, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772622143657711408 X-GMAIL-MSGID: 1772622143657711408 From: Thomas Gleixner For the write_atomic callback, the console driver may have unsafe regions that need to be appropriately marked. Provide functions that accept the nbcon_write_context struct to allow for the driver to enter and exit unsafe regions. Co-developed-by: John Ogness Signed-off-by: John Ogness Signed-off-by: Thomas Gleixner (Intel) --- include/linux/console.h | 4 ++++ kernel/printk/printk_nbcon.c | 41 +++++++++++++++++++++++++++++++++++- 2 files changed, 44 insertions(+), 1 deletion(-) diff --git a/include/linux/console.h b/include/linux/console.h index 3d129b2b70a1..e4ce1015627c 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -456,8 +456,12 @@ static inline bool console_is_registered(const struct console *con) #ifdef CONFIG_PRINTK extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt); +extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt); +extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt); #else static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; } +static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; } +static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; } #endif extern int console_set_on_cmdline; diff --git a/kernel/printk/printk_nbcon.c b/kernel/printk/printk_nbcon.c index e1f0e4278ffa..57b7539bbbb2 100644 --- a/kernel/printk/printk_nbcon.c +++ b/kernel/printk/printk_nbcon.c @@ -761,7 +761,6 @@ EXPORT_SYMBOL_GPL(nbcon_can_proceed); * * Internal helper to avoid duplicated code */ -__maybe_unused static bool nbcon_context_update_unsafe(struct nbcon_context *ctxt, bool unsafe) { struct console *con = ctxt->console; @@ -787,6 +786,46 @@ static bool nbcon_context_update_unsafe(struct nbcon_context *ctxt, bool unsafe) return true; } +/** + * nbcon_enter_unsafe - Enter an unsafe region in the driver + * @wctxt: The write context that was handed to the write function + * + * Return: True if the state is correct. False if ownership was + * handed over or taken. + * + * When this function returns false then the calling context is no longer + * the owner and is no longer allowed to go forward. In this case it must + * back out immediately and carefully. The buffer content is also no longer + * trusted since it no longer belongs to the calling context. + */ +bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) +{ + struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); + + return nbcon_context_update_unsafe(ctxt, true); +} +EXPORT_SYMBOL_GPL(nbcon_enter_unsafe); + +/** + * nbcon_exit_unsafe - Exit an unsafe region in the driver + * @wctxt: The write context that was handed to the write function + * + * Return: True if the state is correct. False if ownership was + * handed over or taken. + * + * When this function returns false then the calling context is no longer + * the owner and is no longer allowed to go forward. In this case it must + * back out immediately and carefully. The buffer content is also no longer + * trusted since it no longer belongs to the calling context. + */ +bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) +{ + struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); + + return nbcon_context_update_unsafe(ctxt, false); +} +EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); + /** * nbcon_emit_next_record - Emit a record in the acquired context * @wctxt: The write context that will be handed to the write function