From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f54.google.com (mail-qv1-f54.google.com [209.85.219.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E27972627 for ; Sun, 23 Nov 2025 17:51:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763920291; cv=none; b=VumsC7BSnvvecDJhnAHcsuH/tXmAiBItuvnvxg7MDRy0VTUlKkv1QJK/84Qi2++uNJVkoQ5wO4AdjF2Uf/M07B4Osgq+32fmi8X6iS6bNl3z9svfxK29HXQ9QHZBql1MQHtdUSGR0xD1IJbNs/Odi+PaLDE0kxM49kJccbdq2uM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763920291; c=relaxed/simple; bh=coevVS0bxLWItnkBJWH8H9g+QaUHc6q7/7mcsJh4uVw=; h=Subject:From:To:Cc:References:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=ZWScWhyZ9TeLPzX+I6BjJsaNOVMb4aHnEVzw23+uhOdmCILSxlkM3q8iMkvSn8AfVzIpBrUg5AZT+EdDL6KzV3wmlfZcfKW1CZiS9pp3hk7RVZZDarcOtwBqgcABAVP/bn2c/T7wzF8y/s+gi8ZymxeHCZvOADm7hhVdnhkkXVQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=marek.ca; spf=pass smtp.mailfrom=marek.ca; dkim=pass (2048-bit key) header.d=marek.ca header.i=@marek.ca header.b=CXAnPKPv; arc=none smtp.client-ip=209.85.219.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=marek.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=marek.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=marek.ca header.i=@marek.ca header.b="CXAnPKPv" Received: by mail-qv1-f54.google.com with SMTP id 6a1803df08f44-8843ebf2facso50500186d6.1 for ; Sun, 23 Nov 2025 09:51:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marek.ca; s=google; t=1763920288; x=1764525088; darn=vger.kernel.org; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:references:cc:to:from:subject:from:to:cc :subject:date:message-id:reply-to; bh=vIANx9jGl2SWaC9mRIgpqWIi2tjrJHPgyOK0RQo1cKY=; b=CXAnPKPvdVrrkm4DBj6CkK/ndLqhoo4A/A2Rrasg8wcRtEtndIyA2lWj9y54fHhTRN XWqpiS3lIMW2q8M141v03Vj9JsyOr9y1roojWWab8dqNsN2pD/7vvmdoxEoG6GphWL8L oB/wGQ7kbSp2LsxIV+r1oQR2DV6L/OAkhXEesX40l2FaLZTRDZjn1hOqRN++VmOYpZQw vNjIih2p1RYao6sUwP3gi+7y4uSrvfsTOir23JoLTMD20TA/yD0Rg7CmGbYEmD29EK+Q YyYrwXD+OmtStg31fU/Ttl9gGTy89BpdZpkSoV5No7qvpg3bSMTdpRaaMdmQwnYA97Pm VJ6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763920288; x=1764525088; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:references:cc:to:from:subject:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=vIANx9jGl2SWaC9mRIgpqWIi2tjrJHPgyOK0RQo1cKY=; b=U2wRMomSC2/0ltGkLRWegmMve4Oonxlh9fLp7tggcM95oB8sA6MAjycnvUf618tlic W+1HXUob9HT9bAQiYM/bwbOdptC5v2a0j5pq44OPa0y7kJg1DhIUDDwVJxEfQNW9VA0k 3nmmEKCdSe8y974iIBoodk0ALdvwc0DGxxoYl3tzTVqhKWQZg5u1sdFqEvLOeps/VoFM +yHBJDVcmBIX17weoMG6dFBxv1yNp7v+toEOp71yHfQobtPFA3Hwuu9qqadnpBH1aL49 E1HCVEdK8QJTrRsMFZic/Jzak5RRirlA/eFuPJNUYoAEa1gHYYTySkLpiyZLZGXxTg+b EGpg== X-Forwarded-Encrypted: i=1; AJvYcCUxekBgOBTGhaD5Qd7/Yql/CS0pNaMHgqR+v7A3reJ6+Cbbn0l1GuO9B3mmxY+wLRdT0a3Ta2r4T+Z8vGo=@vger.kernel.org X-Gm-Message-State: AOJu0YzGeFKv4Wg5+Rh0szsZ3CdZtDofbA3qEWuGFBtF3mJ2BSangPpg vdL1ojh9BvQqhH1+dRnnD5YScGD6wZ4UQVWy24JjLAvx6YQH0ygMyxwxzWPJhdKcIvXNNWwzLxr KxDid X-Gm-Gg: ASbGncvhWykrBhcuQlneMbkasea9ad+/t2PANsYaJNME77NqVlIv+a/I1Ks+wlJavzR VVhE2DEQKMkAEi+kX4uqqkyExWJaiFuMV8YmOAG9PzhoWEojrxeQp9Cp8rlZyhvk2z0+NE92QKx inPROOUbpE45l61jJS5gabNnzFU7ihK3r/cd+Q0u669mFop4Ir0VE33AOhGlCnmlqws5FtJFlDF qpY0ut72fYAFE+iT6dJNhyyJYu2OHQfrF95enf4BM7PKBOIbm0xH93AxwMezvlSqZyW3bF9EsYe /vMRSo/bInIl5SIiyONlULdj/srFfJfRwBjRYCym+bK79AIXoQBXL5aXN2YpQd+ZOJusb2Jfh8V GuQnF8beQHRhApry0p6Aop/O0znzjRix2lxsapxBGA/7iKE+8j5tegzjow64lpopNZytTqgAX8n 7Q89+WAJfQ1WcWuRdTwZTFqcvOJphAdyY94QwbZuM/6Q4LVYNHq1zq+RVGbA== X-Google-Smtp-Source: AGHT+IGGmRjy6S6jG9UQOZ7re2IoKjO567YiFxEaApg45oVagihjcnDFg0s0qlsPTSkuzLAkIZrimw== X-Received: by 2002:a05:6214:ac6:b0:880:78d6:fa67 with SMTP id 6a1803df08f44-8847c4a3e03mr126072936d6.23.1763920287620; Sun, 23 Nov 2025 09:51:27 -0800 (PST) Received: from [192.168.0.189] (modemcable125.110-19-135.mc.videotron.ca. [135.19.110.125]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8846e5744ddsm84544876d6.45.2025.11.23.09.51.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 23 Nov 2025 09:51:27 -0800 (PST) Subject: Re: [PATCH] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY From: Jonathan Marek To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , James Morse , Douglas Anderson , Trilok Soni , shechenglong , Kuninori Morimoto , Shameer Kolothum , open list References: <20251117051211.16108-1-jonathan@marek.ca> Message-ID: <71ec790c-511d-7b57-a5cb-7c26c46257fe@marek.ca> Date: Sun, 23 Nov 2025 12:50:24 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20251117051211.16108-1-jonathan@marek.ca> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Can you pick this up? Its an urgent fix.. And looks like I forgot it, you can add: Signed-off-by: Jonathan Marek On 11/17/25 12:12 AM, Jonathan Marek wrote: > The "drop print" commit removed the whole branch and not just the print. > For some ARM64 cpus, this leads to hard lockup when > CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not enabled. > > Fixes: 62e72463ca71 ("arm64: proton-pack: Drop print when !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY") > --- > arch/arm64/kernel/proton-pack.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c > index c7d70d04c164c..80a580e019c50 100644 > --- a/arch/arm64/kernel/proton-pack.c > +++ b/arch/arm64/kernel/proton-pack.c > @@ -1032,6 +1032,8 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) > > if (arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE) { > /* No point mitigating Spectre-BHB alone. */ > + } else if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY)) { > + /* Do nothing */ > } else if (supports_ecbhb(SCOPE_LOCAL_CPU)) { > state = SPECTRE_MITIGATED; > set_bit(BHB_HW, &system_bhb_mitigations); >