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Tue, 14 Jan 2025 17:55:27 +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 7D2BD195608A; Tue, 14 Jan 2025 17:55:02 +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: Josh Poimboeuf , 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 , 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 06/30] static_call: Add read-only-after-init static calls Date: Tue, 14 Jan 2025 18:51:19 +0100 Message-ID: <20250114175143.81438-7-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-Rspamd-Queue-Id: 776D440003 X-Rspamd-Server: rspam12 X-Stat-Signature: npjuw5at84d9qbrr87deedoyzqnc9ykp X-Rspam-User: X-HE-Tag: 1736877336-219054 X-HE-Meta: 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 e6Ez4ca6 YhqebmvM6/tRzqdr1jSVsvkW7G0N7Sc5jo59F/ZQiiN5xGnPrfItFeEtJOkx6AULkxWTyOmBouHWAee16HinJ3GY6CikDpuaHNlAE0J0aEbTc988eSnaebQhuxx2q5KbiYg/TtMwjWbPrfM4kvlK+4IwhsQMpB4e22OwXxLnHdQbnfM6QTe5nf7pEBT7B1V9w8ZDJnaXNOvTFzcL8wUuk6GauKdhkAae/pPaLDHsq28XvvqzKcUwfl2jk7CLGydPjB3Cfyn+HgcleqRZuH+urM1pEn5Z34TgwNoXnDtqDw9P6M9rlIupCRK+dgKNCiQ0f8Y8xZqCH15YW8mimgKz8j8BsI53ssZFEJvlVye3hWI3mLLGc7K9SUlOVyTd58aSrdQH2v37ZH1scXQ0eMp6mT2Ccl8yTAVTSupLfpUR5K8PQ4azfThxLZ6oPtA2y0rAeCEMpnZqZ3Pc6OzB4IgvrfQUhPw== 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: From: Josh Poimboeuf Deferring a code patching IPI is unsafe if the patched code is in a noinstr region. In that case the text poke code must trigger an immediate IPI to all CPUs, which can rudely interrupt an isolated NO_HZ CPU running in userspace. If a noinstr static call only needs to be patched during boot, its key can be made ro-after-init to ensure it will never be patched at runtime. Signed-off-by: Josh Poimboeuf --- include/linux/static_call.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/linux/static_call.h b/include/linux/static_call.h index 78a77a4ae0ea8..ea6ca57e2a829 100644 --- a/include/linux/static_call.h +++ b/include/linux/static_call.h @@ -192,6 +192,14 @@ extern long __static_call_return0(void); }; \ ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func) +#define DEFINE_STATIC_CALL_RO(name, _func) \ + DECLARE_STATIC_CALL(name, _func); \ + struct static_call_key __ro_after_init STATIC_CALL_KEY(name) = {\ + .func = _func, \ + .type = 1, \ + }; \ + ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func) + #define DEFINE_STATIC_CALL_NULL(name, _func) \ DECLARE_STATIC_CALL(name, _func); \ struct static_call_key STATIC_CALL_KEY(name) = { \ @@ -200,6 +208,14 @@ extern long __static_call_return0(void); }; \ ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) +#define DEFINE_STATIC_CALL_NULL_RO(name, _func) \ + DECLARE_STATIC_CALL(name, _func); \ + struct static_call_key __ro_after_init STATIC_CALL_KEY(name) = {\ + .func = NULL, \ + .type = 1, \ + }; \ + ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) + #define DEFINE_STATIC_CALL_RET0(name, _func) \ DECLARE_STATIC_CALL(name, _func); \ struct static_call_key STATIC_CALL_KEY(name) = { \