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Mon, 15 Apr 2024 12:06:35 -0700 (PDT) MIME-Version: 1.0 References: <20240415163527.626541-1-jeffxu@chromium.org> <20240415163527.626541-2-jeffxu@chromium.org> In-Reply-To: From: Jeff Xu Date: Mon, 15 Apr 2024 12:06:24 -0700 Message-ID: Subject: Re: [PATCH v10 1/5] mseal: Wire up mseal syscall To: Linus Torvalds Cc: Muhammad Usama Anjum , akpm@linux-foundation.org, keescook@chromium.org, jannh@google.com, sroettger@google.com, willy@infradead.org, gregkh@linuxfoundation.org, corbet@lwn.net, Liam.Howlett@oracle.com, surenb@google.com, merimus@google.com, rdunlap@infradead.org, jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, pedro.falcato@gmail.com, dave.hansen@intel.com, linux-hardening@vger.kernel.org, deraadt@openbsd.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 0012FA0003 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: nx9afpc69e39f9sdcamobz1mhemqda41 X-HE-Tag: 1713207995-286912 X-HE-Meta: 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 nXZbwNlD VnGzodKZ+rV539pUicW+BSHqCBH0wTJUI613A78iHAKkPmtFQnM0248izZiq0WhBym2a5+k8zPfnfYp2vkHWLRyd9nZ+58Ld1sVD2kDfufs77lS5vDBbNpXVYODleNijnwJnHzobmI196176WBXZ1FJ5yqBHYzJw7Ro0NEVw3rbYnhjo/g5FGBoFPYTjDq1iwZ23GVwGBiZ/EyGAS+Pf2mv8TTdTjkAdVvXFzyy8gObmWEh7ya09bKz2cKJCLxHrBv/LzDNyyzEtukY75PBk8nTG8HwhCmJaQ+qTqdK5fKPX+2PrF4uJDtPBEcP7cqxPoUkhZcDmsSnNKkWEuLYmtFrzhqvEhv/XWp1plp5CesMN1fVTxwX3KoZ4JkPx88OECmGHVShvTeWcccsf8kC91Oh+AFkwKhHfJbvHW X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 15, 2024 at 11:21=E2=80=AFAM Linus Torvalds wrote: > > On Mon, 15 Apr 2024 at 11:11, Muhammad Usama Anjum > wrote: > > > > It isn't logical to wire up something which isn't present > > Actually, with system calls, the rules end up being almost opposite. > > There's no point in adding the code if it's not reachable. So adding > the system call code before adding the wiring makes no sense. > > So you have two cases: add the stubs first, or add the code first. > Neither does anything without the other. > > So then you go "add both in the same commit" option, which ends up > being horrible from a "review the code" standpoint. The two parts are > entirely different and mixing them up makes the patch very unclear > (and has very different target audiences for reviewing it - the MM > people really shouldn't have to look at the architecture wiring > parts). > > End result: there are no "this is the logical ordering" cases. > > But the "wire up system calls" part actually has some reasons to be first= : > > - it reserves the system call number > > - it adds the "when system call isn't enabled, return -ENOSYS" > conditional system call logic > > so I actually tend prefer this ordering when it comes to system calls. > I confirm that the wire up change can be merged by its own, i.e. build will pass, and -ENOSYS will be returned at runtime. Thanks Linus for clarifying this. -Jeff > Linus