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Tue, 14 Jan 2025 18:01:45 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.39.192.55]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8F01A195E3EA; Tue, 14 Jan 2025 18:01:23 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux.dev, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-perf-users@vger.kernel.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, linux-arch@vger.kernel.org, rcu@vger.kernel.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com Cc: Juergen Gross , Ajay Kaher , Alexey Makhalov , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Boris Ostrovsky , Josh Poimboeuf , Pawan Gupta , Sean Christopherson , Paolo Bonzini , Andy Lutomirski , Arnd Bergmann , Frederic Weisbecker , "Paul E. McKenney" , Jason Baron , Steven Rostedt , Ard Biesheuvel , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Juri Lelli , Clark Williams , Yair Podemsky , Tomas Glozar , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Kees Cook , Andrew Morton , Christoph Hellwig , Shuah Khan , Sami Tolvanen , Miguel Ojeda , Alice Ryhl , "Mike Rapoport (Microsoft)" , Samuel Holland , Rong Xu , Nicolas Saenz Julienne , Geert Uytterhoeven , Yosry Ahmed , "Kirill A. Shutemov" , "Masami Hiramatsu (Google)" , Jinghao Jia , Luis Chamberlain , Randy Dunlap , Tiezhu Yang Subject: [PATCH v4 21/30] context_tracking: Explicitely use CT_STATE_KERNEL where it is missing Date: Tue, 14 Jan 2025 18:51:34 +0100 Message-ID: <20250114175143.81438-22-vschneid@redhat.com> In-Reply-To: <20250114175143.81438-1-vschneid@redhat.com> References: <20250114175143.81438-1-vschneid@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250114_180209_023753_812DC06A X-CRM114-Status: GOOD ( 15.73 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org CT_STATE_KERNEL being zero means it can be (and is) omitted in a handful of places. A later patch will change CT_STATE_KERNEL into a non-zero value, prepare that by using it where it should be: o In the initial CT state o At kernel entry / exit No change in functionality intended. Signed-off-by: Valentin Schneider --- kernel/context_tracking.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 938c48952d265..a61498a8425e2 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -31,7 +31,7 @@ DEFINE_PER_CPU(struct context_tracking, context_tracking) = { .nesting = 1, .nmi_nesting = CT_NESTING_IRQ_NONIDLE, #endif - .state = ATOMIC_INIT(CT_RCU_WATCHING), + .state = ATOMIC_INIT(CT_RCU_WATCHING | CT_STATE_KERNEL), }; EXPORT_SYMBOL_GPL(context_tracking); @@ -147,7 +147,7 @@ static void noinstr ct_kernel_exit(bool user, int offset) instrumentation_end(); WRITE_ONCE(ct->nesting, 0); /* Avoid irq-access tearing. */ // RCU is watching here ... - ct_kernel_exit_state(offset); + ct_kernel_exit_state(offset - CT_STATE_KERNEL); // ... but is no longer watching here. rcu_task_exit(); } @@ -175,7 +175,7 @@ static void noinstr ct_kernel_enter(bool user, int offset) } rcu_task_enter(); // RCU is not watching here ... - ct_kernel_enter_state(offset); + ct_kernel_enter_state(offset + CT_STATE_KERNEL); // ... but is watching here. instrumentation_begin(); @@ -537,7 +537,7 @@ void noinstr __ct_user_enter(enum ctx_state state) * RCU only requires CT_RCU_WATCHING increments to be fully * ordered. */ - raw_atomic_add(state, &ct->state); + raw_atomic_add(state - CT_STATE_KERNEL, &ct->state); } } } @@ -647,7 +647,7 @@ void noinstr __ct_user_exit(enum ctx_state state) * RCU only requires CT_RCU_WATCHING increments to be fully * ordered. */ - raw_atomic_sub(state, &ct->state); + raw_atomic_sub(state - CT_STATE_KERNEL, &ct->state); } } }