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Tue, 27 Oct 2026 14:30:32 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.87.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 27 Oct 2026 14:30:32 +0000 (GMT) From: Heiko Carstens To: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Ilya Leoshkevich Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v2 07/10] s390/nospec-branch: Serialize text patching with text_mutex Date: Tue, 27 Oct 2026 15:30:27 +0100 Message-ID: <20261027143030.3154657-8-hca@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261027143030.3154657-1-hca@linux.ibm.com> References: <20261027143030.3154657-1-hca@linux.ibm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDI3MDA1NiBTYWx0ZWRfX7r4kjAlBm1Jc zxxgRWtSF0dG/+5TRvpc6aVVX9Wb32PsfjAmff5+BQT8I0mieDyVbjUdUBQQErvEk0RNCC6lwZl XZkoy+fz+cd7EYKvow00hdqWm8/DVMo= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDI3MDA1NiBTYWx0ZWRfX40dbjl/rsd+9 JeDmdb2l6HMG8mBR/eb/fhUnwDT3hk806ChbH9Wvldc49L9FCs+RDERzGDHvaf2nKhZw7chROsu 7Mxfqo9KFmu/UnsE6adefoumf4Iy2xZECSaXMZfBEOkFATgWivHkalnqJRoUX067QPgh/ORpxSM JMOqgOX8dZ/4HxGZhTKhXzq3+KY7I6QSH6rfEK3mEELANGDLGdL+tlRFDc7GjCCwW2PoSbl2R33 xozszeXXiNdv3oc9k1+jHw7/b8Qjk91S7m05Q26TL5cEoM85A8nG7yHkwFHTwWIV1QUv2y3gWEN XANTiaqIpoWmAIkUG6C4KlQLYYO0dzQf8+6OLdMX6g4bopuAS2tMnKxc9bvQzmxX0IfH+ndwFWJ hkpYA/GlsSnukG8ak38TZtO7KV/a/Z5wBeh47drPsDxot73hsi3dsCUe/J1rgIsIPOXOl3+7T74 8mPfHtGhQhiZ798Kv7w== X-Proofpoint-ORIG-GUID: aNrq8SaD4EAmg3aleOyTL1bVIhZdt-D6 X-Authority-Analysis: v=2.4 cv=Uu32pOwB c=1 sm=1 tr=0 ts=6ae0b58f cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=fwsI9ysbrLTR6U1S1t8A:9 X-Proofpoint-GUID: aNrq8SaD4EAmg3aleOyTL1bVIhZdt-D6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-10-27_03,2026-10-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 priorityscore=1501 spamscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610190000 definitions=main-2610270056 Acquire text_mutex inside __nospec_revert() around the patching loop. Serialization is not required for __nospec_revert(), however this is part of larger series where at the end s390_kernel_write() requires that callers hold text_mutex. Signed-off-by: Heiko Carstens --- arch/s390/kernel/nospec-branch.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c index e11ec15960a1..26cd5b278e8a 100644 --- a/arch/s390/kernel/nospec-branch.c +++ b/arch/s390/kernel/nospec-branch.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 +#include #include #include #include @@ -108,6 +109,7 @@ static void __init_or_module __nospec_revert(s32 *start, s32 *end) /* Second part of the instruction replace is always a nop */ memcpy(insnbuf + 2, branch, sizeof(branch)); + guard(mutex)(&text_mutex); for (epo = start; epo < end; epo++) { instr = (u8 *) epo + *epo; if (instr[0] == 0xc0 && (instr[1] & 0x0f) == 0x04) -- 2.53.0