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 F38FC283FDD for ; Mon, 24 Nov 2025 14:41:10 +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=1763995271; cv=none; b=LUc70hY8XQgoP00eJm+b29rJ7+GyYO2nYtXQ9i754QH5gRUjuQo5lgfQlBnIubFkgbufEIXCvW6HEvYb5ILaNsAT2xbHo2CXcMPN6WX/CvVjEiipuCYr5CyRwjPcwpLZLM/tPgRNiFXO5PKGIjrBWeVvnmQGAu5Js96w4Rzzjp0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763995271; c=relaxed/simple; bh=XncGfPrcCJsYArhUGXo8sANatKFrQIfr4atzE1U5wz4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=IuOZ1I5NRBqvN5f0rOPyayW/RGJc557jrtOWiAKYg03jUh4+lgiv9y7vIQG4IrrwQaOp4wsCwt/HJCHQE8A6/ikZBUASELNHr2z2En/JKjOh4gFVytdECNDU65n+MzleNwIxNgp6zI3qwuRl3vHcX3U/MIpYtkRFR84DVhK1c2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nEwlnCMf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nEwlnCMf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4968CC116D0; Mon, 24 Nov 2025 14:41:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763995270; bh=XncGfPrcCJsYArhUGXo8sANatKFrQIfr4atzE1U5wz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nEwlnCMf536/aUl1zrHR8DlxDK9Wuqz7X4+J5Dn65GfOULKeqYgDkfcVnGGA0xGpe KP4T2dGCf6MNFiJXOgLq8uj3cxHJYNkqUZVdpcD47pHrB/kM5jOe2VRVAyCEDecdaR Yk0MDoVtjL/ttnfqaDyTTCQGgT+EosFnRYeEpNCWbaFHPngcR/TIw/jwHVlzlZsVXt Vp2eWtg249NKera8L0wTAwNYsPgwDP5p/viZQkZTlnVRGmLtzt4F1UPE8gm85Oppy6 A5mC/p6NDtatl/uSdvxzkvHhEwItGVTkxfTKiVRwiK3HiNg5qt7GIgbVTQsa3Ko+xz JMrDuGy5g0q9g== From: Will Deacon To: linux-arm-kernel@lists.infradead.org, Jonathan Marek Cc: catalin.marinas@arm.com, kernel-team@android.com, Will Deacon , James Morse , Douglas Anderson , Trilok Soni , shechenglong , Kuninori Morimoto , Shameer Kolothum , linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY Date: Mon, 24 Nov 2025 14:41:02 +0000 Message-Id: <176399113353.3273155.581458888814324419.b4-ty@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251117051211.16108-1-jonathan@marek.ca> References: <20251117051211.16108-1-jonathan@marek.ca> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit On Mon, 17 Nov 2025 00:12:08 -0500, 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. > > Applied (with your SoB) to arm64 (for-next/fixes), thanks! [1/1] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY https://git.kernel.org/arm64/c/165eb13e485c I'd be inclined to remove CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY entirely (i.e. make it unconditional) given the number of CPUs affected and the dynamic controls we already have for the mitigation. Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev