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 5F6FE2F44; Thu, 12 Dec 2024 17:03:37 +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=1734023017; cv=none; b=q7Egz8DbMnOhh1RNriTcg4cbaegy/ZrQfn3rVEmAf94CqMpq7ei55V/DdNntwkW3IwTFvd042xEYlZ875dkOcKCHEtP2Cr3si29hNekNonw1+QnZwjyiAjtHGFSwQZvrtPcR7fstwcaP0EXSJXSqEewGoMV7R1LqgpyOJvdZ8f4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734023017; c=relaxed/simple; bh=ZyPMEWBXh7NEVhr6e647IczXv3crpHErFD1TOH0T9qA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=goUEj78X4H7BMUiNSqHkltTfWeE/vuVCrb6qdAVkSKs+JdWYdTCIUTjB1jQj6MoRsnCCeVz9qVGEAcBkINKKp8RMDeKIZYth7czjd6oDOFMFRFbgfb8Djeg6a2d32DQtUx3yWeW9IrXW/Cvnq7GxehWjwNnmtB2iQVnt6GsqbQc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=x8OrxC2c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="x8OrxC2c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A27E2C4CECE; Thu, 12 Dec 2024 17:03:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734023017; bh=ZyPMEWBXh7NEVhr6e647IczXv3crpHErFD1TOH0T9qA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x8OrxC2camF4wZIj4dzo3nK39IIT5njn3oddsfY1nTFHeG/gPeCEjggWwYwIvwq5P A3Wo+3/hFyv2dezGYyeg91+5WG1g+K4uGzzPy/BkhIxUQIlmmJV1qBNHqSug4S1ZaX AUCvlwoEIB42l4BpGfb9hF3uEXM5dBmF7qQoTmBE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oleksandr Ocheretnyi , Guenter Roeck , Mika Westerberg , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 5.15 398/565] iTCO_wdt: mask NMI_NOW bit for update_no_reboot_bit() call Date: Thu, 12 Dec 2024 15:59:53 +0100 Message-ID: <20241212144327.382894076@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144311.432886635@linuxfoundation.org> References: <20241212144311.432886635@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleksandr Ocheretnyi [ Upstream commit daa814d784ac034c62ab3fb0ef83daeafef527e2 ] Commit da23b6faa8bf ("watchdog: iTCO: Add support for Cannon Lake PCH iTCO") does not mask NMI_NOW bit during TCO1_CNT register's value comparison for update_no_reboot_bit() call causing following failure: ... iTCO_vendor_support: vendor-support=0 iTCO_wdt iTCO_wdt: unable to reset NO_REBOOT flag, device disabled by hardware/BIOS ... and this can lead to unexpected NMIs later during regular crashkernel's workflow because of watchdog probe call failures. This change masks NMI_NOW bit for TCO1_CNT register values to avoid unexpected NMI_NOW bit inversions. Fixes: da23b6faa8bf ("watchdog: iTCO: Add support for Cannon Lake PCH iTCO") Signed-off-by: Oleksandr Ocheretnyi Reviewed-by: Guenter Roeck Reviewed-by: Mika Westerberg Link: https://lore.kernel.org/r/20240913191403.2560805-1-oocheret@cisco.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin --- drivers/watchdog/iTCO_wdt.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c index a8052a3faaabb..3cebb83b3e679 100644 --- a/drivers/watchdog/iTCO_wdt.c +++ b/drivers/watchdog/iTCO_wdt.c @@ -82,6 +82,13 @@ #define TCO2_CNT(p) (TCOBASE(p) + 0x0a) /* TCO2 Control Register */ #define TCOv2_TMR(p) (TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/ +/* + * NMI_NOW is bit 8 of TCO1_CNT register + * Read/Write + * This bit is implemented as RW but has no effect on HW. + */ +#define NMI_NOW BIT(8) + /* internal variables */ struct iTCO_wdt_private { struct watchdog_device wddev; @@ -220,13 +227,23 @@ static int update_no_reboot_bit_cnt(void *priv, bool set) struct iTCO_wdt_private *p = priv; u16 val, newval; - val = inw(TCO1_CNT(p)); + /* + * writing back 1b1 to NMI_NOW of TCO1_CNT register + * causes NMI_NOW bit inversion what consequently does + * not allow to perform the register's value comparison + * properly. + * + * NMI_NOW bit masking for TCO1_CNT register values + * helps to avoid possible NMI_NOW bit inversions on + * following write operation. + */ + val = inw(TCO1_CNT(p)) & ~NMI_NOW; if (set) val |= BIT(0); else val &= ~BIT(0); outw(val, TCO1_CNT(p)); - newval = inw(TCO1_CNT(p)); + newval = inw(TCO1_CNT(p)) & ~NMI_NOW; /* make sure the update is successful */ return val != newval ? -EIO : 0; -- 2.43.0