From nobody Fri Oct 24 20:35:20 2025 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 E87C9C2BB47 for ; Mon, 15 Aug 2022 23:01:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352926AbiHOXB2 (ORCPT ); Mon, 15 Aug 2022 19:01:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352512AbiHOW6f (ORCPT ); Mon, 15 Aug 2022 18:58:35 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E401474E0; Mon, 15 Aug 2022 12:56:52 -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 ams.source.kernel.org (Postfix) with ESMTPS id 0F800B80EAB; Mon, 15 Aug 2022 19:56:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55B02C433D6; Mon, 15 Aug 2022 19:56:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660593409; bh=Jl6YcRGxZmnFIQ7S0vKwAI423njHCiOFiSTN7qLkT9A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eO5dRmm3PrY26leKDntummwSKQsNDY2F47jqEkZIYf7Pz6D+dmmtfhfb0Eqy49a6J 1uTnHf/WsoiGOdTtYfMsFXCNf5zl4Hfv8dxPwfsTNztnVpKxU3J/inljMjFD2a+odo f/83e0NxQwLXyU44zQeL4MfASJnhkNmhJa+aOVSY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiko Carstens , Alexander Gordeev , Sasha Levin Subject: [PATCH 5.18 0924/1095] s390/smp: enforce lowcore protection on CPU restart Date: Mon, 15 Aug 2022 20:05:23 +0200 Message-Id: <20220815180507.484901030@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Alexander Gordeev [ Upstream commit 6f5c672d17f583b081e283927f5040f726c54598 ] As result of commit 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") the low-address protection bit gets mistakenly unset in control register 0 save area of the absolute zero memory. That area is used when manual PSW restart happened to hit an offline CPU. In this case the low-address protection for that CPU will be dropped. Reviewed-by: Heiko Carstens Fixes: 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is c= alled") Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin --- arch/s390/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 2cef49983e9e..3327412f82a6 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -508,8 +508,8 @@ static void __init setup_lowcore_dat_on(void) S390_lowcore.svc_new_psw.mask |=3D PSW_MASK_DAT; S390_lowcore.program_new_psw.mask |=3D PSW_MASK_DAT; S390_lowcore.io_new_psw.mask |=3D PSW_MASK_DAT; - __ctl_store(S390_lowcore.cregs_save_area, 0, 15); __ctl_set_bit(0, 28); + __ctl_store(S390_lowcore.cregs_save_area, 0, 15); put_abs_lowcore(restart_flags, RESTART_FLAG_CTLREGS); put_abs_lowcore(program_new_psw, lc->program_new_psw); for (cr =3D 0; cr < ARRAY_SIZE(lc->cregs_save_area); cr++) --=20 2.35.1