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Thu, 24 Jul 2025 16:16:30 +0000 From: Prakash Sangappa To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, tglx@linutronix.de, bigeasy@linutronix.de, kprateek.nayak@amd.com, vineethr@linux.ibm.com, prakash.sangappa@oracle.com Subject: [PATCH V7 06/11] Add API to query supported rseq cs flags Date: Thu, 24 Jul 2025 16:16:20 +0000 Message-ID: <20250724161625.2360309-7-prakash.sangappa@oracle.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250724161625.2360309-1-prakash.sangappa@oracle.com> References: <20250724161625.2360309-1-prakash.sangappa@oracle.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-07-24_02,2025-07-24_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 bulkscore=0 suspectscore=0 mlxscore=0 phishscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2507240123 X-Proofpoint-GUID: yh9zTwq3BvkqmRkFCyaZ5oPXayHU44RB X-Proofpoint-ORIG-GUID: yh9zTwq3BvkqmRkFCyaZ5oPXayHU44RB X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzI0MDEyMyBTYWx0ZWRfX/AGEUbNoFjD3 SP0l2aEWqPSzDGkWn4CMnLD1aLv8MWZwTHh4Q8IUpftusBWmzjIY/yDCDDB0s291wkeX9gvT3f3 6e2UrvqgRn7Fwliqtv7XW9TYde1guLDndQvbdwuC5lxN/PKgfqOZw+x4bK4pkAVFfvW9UMxGuci UMfJ8RDo5guoIcf2AML7o0PPDbgTpKLfnQHvdJ/+sB0opvs9cThlK3kBwcCSqYTvCw2VqMfBwET qRk7dPWykOqBveB4UBy5m60xqZfgrdimiGWDL7902MQHGJGAAZE0M+e+3nrBH4xbg72/Wocvjz1 k/aNqbmN9dkSbtltg6jlNY89muV+qZZcUzFEe+ktwCv+II9inrCCvTTPxGUIX04QkFdsFcICokE z1E2ARZL7gIeQV9Vwv2kOCXoLAJ7W2MCDkOPZ1VEPZpeRo8JKMgm73FcRyXiaDfRzCxDbNYK X-Authority-Analysis: v=2.4 cv=IPoCChvG c=1 sm=1 tr=0 ts=68825c5f b=1 cx=c_pps a=zPCbziy225d3KhSqZt3L1A==:117 a=zPCbziy225d3KhSqZt3L1A==:17 a=Wb1JkmetP80A:10 a=yPCof4ZbAAAA:8 a=XZOol5B-I9QkcwWuj0oA:9 cc=ntf awl=host:12061 Content-Type: text/plain; charset="utf-8" For the API, add a new flag to sys_rseq 'flags' argument called RSEQ_FLAG_QUERY_CS_FLAGS. When this flag is passed it returns a bit mask of all the supported rseq cs flags in the user provided rseq struct's 'flags' member. Signed-off-by: Prakash Sangappa --- include/uapi/linux/rseq.h | 1 + kernel/rseq.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index 015534f064af..44baea9dd10a 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -20,6 +20,7 @@ enum rseq_cpu_id_state { =20 enum rseq_flags { RSEQ_FLAG_UNREGISTER =3D (1 << 0), + RSEQ_FLAG_QUERY_CS_FLAGS =3D (1 << 1), }; =20 enum rseq_cs_flags_bit { diff --git a/kernel/rseq.c b/kernel/rseq.c index 6ca3ca959b66..7f4daeba6d0d 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -550,6 +550,21 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32,= rseq_len, return 0; } =20 + /* + * Return supported rseq_cs flags. + */ + if (flags & RSEQ_FLAG_QUERY_CS_FLAGS) { + u32 rseq_csflags =3D RSEQ_CS_FLAG_DELAY_RESCHED | + RSEQ_CS_FLAG_RESCHEDULED; + if (!IS_ENABLED(CONFIG_RSEQ_RESCHED_DELAY)) + return -EINVAL; + if (!rseq) + return -EINVAL; + if (copy_to_user(&rseq->flags, &rseq_csflags, sizeof(u32))) + return -EFAULT; + return 0; + } + if (unlikely(flags)) return -EINVAL; =20 --=20 2.43.5