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smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-c45ff70000001609-b9-68ec7fdcf266 Date: Mon, 13 Oct 2025 13:28:07 +0900 From: Byungchul Park To: Mark Rutland Cc: linux-kernel@vger.kernel.org, kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, harry.yoo@oracle.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, yunseong.kim@ericsson.com, ysk@kzalloc.com, yeoreum.yun@arm.com, netdev@vger.kernel.org, matthew.brost@intel.com, her0gyugyu@gmail.com, corbet@lwn.net, catalin.marinas@arm.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, sumit.semwal@linaro.org, gustavo@padovan.org, christian.koenig@amd.com, andi.shyti@kernel.org, arnd@arndb.de, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, surenb@google.com, mcgrof@kernel.org, petr.pavlu@suse.com, da.gomez@kernel.org, samitolvanen@google.com, paulmck@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, chuck.lever@oracle.com, neil@brown.name, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com, trondmy@kernel.org, anna@kernel.org, kees@kernel.org, bigeasy@linutronix.de, clrkwllms@kernel.org, ada.coupriediaz@arm.com, kristina.martsenko@arm.com, wangkefeng.wang@huawei.com, broonie@kernel.org, kevin.brodsky@arm.com, dwmw@amazon.co.uk, shakeel.butt@linux.dev, ast@kernel.org, ziy@nvidia.com, yuzhao@google.com, baolin.wang@linux.alibaba.com, usamaarif642@gmail.com, joel.granados@kernel.org, richard.weiyang@gmail.com, geert+renesas@glider.be, tim.c.chen@linux.intel.com, linux@treblig.org, alexander.shishkin@linux.intel.com, lillian@star-ark.net, chenhuacai@kernel.org, francesco@valla.it, guoweikang.kernel@gmail.com, link@vivo.com, jpoimboe@kernel.org, masahiroy@kernel.org, brauner@kernel.org, thomas.weissschuh@linutronix.de, oleg@redhat.com, mjguzik@gmail.com, andrii@kernel.org, wangfushuai@baidu.com, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-i2c@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, rcu@vger.kernel.org, linux-nfs@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH v17 09/47] arm64, dept: add support CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64 Message-ID: <20251013042807.GB6925@system.software.com> References: <20251002081247.51255-1-byungchul@sk.com> <20251002081247.51255-10-byungchul@sk.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02Sb0zMcRzH9/39v+P069R8k82cNVsbyWx9NmZ4YL8HTGYzfx5w9ONu6til KLPKvw6xnA3dLXXoOlzkGpLiRKVLKUs7UbhocTl13TWqu7k7M569vu/3Z6/v58GHI+U99GxO rTkgajXKdAUjpaTfp5sW9uUNqxbf1UVBT4Gdgs7btxAE9M0sXOzSk+B+5kXww1yEwDBoZOGz vRBB2dUaBibbX5EwVB16NliOMvCl+B4JpUY9gmPX7jDQ5Z4i4IN5kALjpSECzPkJ4LIYWHAP 6hnwdX8iQFfnp8B08joF9Q2tFOgCPgTNtS4Ciqrv0dBpb6OhrfkFBZ8+OmmoaX9JQpXnKgNm /w8WWs7aCajweUhw9I2xcOF1OQMTlU0IHBMOArylQRpudYW+LjiHQPd8nISf1QM0lPqSoSrQ g8DY1M+uXCxYr1iRMDmhR0JF2zAjTPjfMML59oXCQ0MfK5TbsoQaS6Jwrf4rIZi8flqw3TzF CO976hnB09HBCldaNwhPSq2s8C44QKbGbZUuTxPT1dmiNmnFDqnKNWin9ttiDllOnafz0feo 00jCYX4prnpnoP9y2YPjVJgpPgFXjldGmOEXYKfzFxnmmBAX1flCuZQjeVM8brB2RoqZ/HY8 daObCLOMT8HvbaNEeEjOH0U4/46O/FNE49aSzxErySdiZ/BraIgLcTyuDHLhWBKKTQ9HIgvF 8vOx/X5LxIP5fgke9ZxAfzaNw08tTqoY8Yb/tIb/tIZ/2nJE3kRytSY7Q6lOX7pIlaNRH1q0 a1+GDYWuzXxkalst8nZubEQ8hxTTZapHbpWcVmZn5mQ0IsyRihhZyuFhlVyWpszJFbX7tmuz 0sXMRhTPUYpZsiXjB9Pk/B7lAXGvKO4XtX9bgpPMzkdz8ua6O3rT6Nje1MliY7Sidtqcg7uS e+PPRu+8VFaM512uS3a4StpXeJ6ht99a/IWP+198SPLG0Zq3qbnB4bGMgb7AWFKMI6r2zTqj ZXzNlnm5uw+vPlMyYimQxCqzRtZLt03rrl43P88y5C0MrBqdYUipcEna/Gs3LysY2WRtalJQ mSplciKpzVT+BqaXzE1pAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA02SbUxTZxTH89z73Bc6ul07jDeQJUs3Y8SoM7p4Msxi/KB3LDP7sMTMxGAz b2zDm2kRxcUIFCI6o7SzdLSKFEep0AkWlCHpJBjrgFWpVGWOipgKVNoxWYtDSvGWZZlfTn7n /3LyfHhYUpGg0llNQZGoLVDlKWkZlu3M0q8dORZWf/T7i9XwoKwHQyxaheFcq5OGKlctBYOX WxCMxqoQvJy3klDZtYhhwehhIDr3BwOLbg+CGp+RBGdHGQF/tyVomLo5g8A0FqTBHCrDMG0/ hcAybmUgdGsHREa7KVgMTBDwcDaMwB5MEBDsOY5goSYXLjS00zDvvUuC2TSIwDYWIGGyTTI7 PI8RuB3lNDyrvkrCUPBt8MemaegzfUdDxHeOgD/baKgvd1Nw3mpEoL/YSkPNeReGrifXGfBN xQkYqTES0OL6Akbt4xgGqhsI6X1S6soKsJr1hDQmCTD91E3AnL2Zgd8ujmCwl64Eq3eIgqcO CwPxsQ2wWF8InpYJBgJnTBguR+5SW01IeFl5GgvN7dcIofLeAi0465xImH9lREK0UU8KldXS ejM8TQoV7YeExoEwLbyK3acF92w9FvobeMHgXSt0WQKMUPHLI+bLT3bLtuwT8zTFonb9p3tl 6qfjPfiAK+2w44SBKkWRd06iFJbnNvEXOitwkjG3km+abVpimlvFDw/PkUlOk/jU9aiky1iS s2XwbufgkvEul8PHL/mJJMu5zfyI6wWRDCm4csSXtlaR/xrL+L7a4NJVksvkhxMhKcRKnME3 JdiknCLJtq6/qCQv5z7ge67dJqqR3PJG2/JG2/J/ux6RzShNU1Ccr9LkfbxOl6suKdAcXvdN Yb4LSb/SfjRu+BlFh3b0Io5FylS5untKraBUxbqS/F7Es6QyTb7527BaId+nKjkiagtztAfz RF0vymCxcoU8e5e4V8HtVxWJuaJ4QNT+5xJsSnopavznkR+fyDkZOHtcf+f5j1lnFRMtX7X2 RTfKfP2h9DX+eXJLaNuRnbHs3u3esgann+Ft34/1v0cdelY3MGNYvudewKCd+GxyTXnEQXm3 vu/+nMlMXWa+6nqr88YuWx16/uuxBarzccfMDxXZDl+7L27+8ODXp4n81LmsGY/PXlukxDq1 akMmqdWpXgMpcDDEkQMAAA== X-CFilter-Loop: Reflected On Fri, Oct 03, 2025 at 03:36:42PM +0100, Mark Rutland wrote: > On Thu, Oct 02, 2025 at 05:12:09PM +0900, Byungchul Park wrote: > > dept needs to notice every entrance from user to kernel mode to treat > > every kernel context independently when tracking wait-event dependencies. > > Roughly, system call and user oriented fault are the cases. > > > > Make dept aware of the entrances of arm64 and add support > > CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64. > > > > Signed-off-by: Byungchul Park > > --- > > arch/arm64/Kconfig | 1 + > > arch/arm64/kernel/syscall.c | 7 +++++++ > > arch/arm64/mm/fault.c | 7 +++++++ > > 3 files changed, 15 insertions(+) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index e9bbfacc35a6..a8fab2c052dc 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -281,6 +281,7 @@ config ARM64 > > select USER_STACKTRACE_SUPPORT > > select VDSO_GETRANDOM > > select VMAP_STACK > > + select ARCH_HAS_DEPT_SUPPORT > > help > > ARM 64-bit (AArch64) Linux support. > > > > diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c > > index c442fcec6b9e..bbd306335179 100644 > > --- a/arch/arm64/kernel/syscall.c > > +++ b/arch/arm64/kernel/syscall.c > > @@ -7,6 +7,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -96,6 +97,12 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, > > * (Similarly for HVC and SMC elsewhere.) > > */ > > > > + /* > > + * This is a system call from user mode. Make dept work with a > > + * new kernel mode context. > > + */ > > + dept_update_cxt(); > > As Mark Brown pointed out in his replies, this patch is missing a whole > bunch of cases and does not work correctly as-is. > > As Dave Hansen pointed out on the x86 patch, you shouldn't do this > piecemeal in architecture code, and should instead work with the > existing context tracking, e.g. by adding logic to > enter_from_user_mode() and exit_to_user_mode(), or by reusing some I will consider it. However, I need to check if there are not any waits and events before enter_from_user_mode(), or after exit_to_user_mode() since those functions aren't the outmost functions for kernel mode C code anyway. Byungchul > existing context tracking logic that's called there. > > Mark.