From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.128.44 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792646263; b=xA1+R68lhSO3V5BMh6pRYxbAlQoZ98qKlwd+DGZzW2/HweBzOKGFbs0eGm9kN1d27s8F h9jzCi0W/E6duCHSYSMoHw6HWPhsinu8eU6+W8hUYjz6TsKw7aEgI9GzWKnRxfjKxqiqo BwIpwiAQTypKYS923MEF6xdFx7dvGQJ+gA52ak00bCK9jPm+2uVS3Kq6ZHYT6M3+U4ULB R8jFqacvBS9Z6tI6LYdexCoU8rqF5OvpZfOEOFAZzi0kTEcDTR7faqYzWLC3tPjA71qC3 aLIzxcgNkG5gzAWOw14XnX9EC8r4FkGv1zYIdezO4zbI7kTdM3E9/WKMRNkhC0ymVLA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792646263; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-Id:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=kNAQ43P7mOXqvjFIm1UIgh+LHBg4TUD3j/lYh+CFxWo=; b=n1dA0WBKwHxOhPmbn6dT+jfUAOnwzYry5wX+mUfNv7VqxSly4vb7lN1bTRGWEanKvN/r lEk7UGV7n67FhEsMW7Se4kaMEQxuXwI5kuRto0TjCQ+AOOOGTePyuZoyDBSTuUV2v9Ixe z/7Mz01ubPi7lZBCbkm+7EXBB+6vxxOueIrgHCMX7jEbxr7bNXpSdCkQcx+xTkw2qpWIX +1dCFGVCGxDIlIXA2t08Bn3asqzCzishs1XrmsMYe41sA6XlfoRIpM+bhuO9vQHOs/Naq bc/GY7VFx0EBUEgNMWmbGUwjTAdNuXwyDk02l4sPLRkZIZv6q6TYqhIaiA6C2qb4uEQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=sVoa5sPI; arc=none smtp.remote-ip=209.85.128.44 Received: from mail-wm1-f44.google.com (mail-wm1-f44.google.com [209.85.128.44]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 417F260A261F for ; Thu, 22 Oct 2026 05:17:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 417F260A261F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=sVoa5sPI Received: by mail-wm1-f44.google.com with SMTP id 5b1f17b1804b1-4a2001dd4e7so14050425e9.3 for ; Wed, 21 Oct 2026 22:17:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792646262; x=1793251062; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=kNAQ43P7mOXqvjFIm1UIgh+LHBg4TUD3j/lYh+CFxWo=; b=sVoa5sPIaKdctHZpZqX/Tr/a3nD/WcLeHZH9WemG0HXKqTdFFgQaFQZ4Cur//1TVtP +IJn6IC0dDP6m4vxjQWZ5aR79dbKnXLHOPNUVurEmFnZV/yqzsl/muVxW+cMH/0zPQdd dK/8pqIuUUk9dLZUuIQTWEglQ5bCKqg/XsY7lVX/kuRlghT8EUfinDMS4f2mkQ8Mt9Fz EmXEQVQ/l6Wtatrq/tc7Is3h3kRt4DHc0JnYD0UP1IIfrpj77eW+iAD7w+r8XxYlAHrZ EElQx2RYSJCa1tDUa2Y9+3pFcnzxyHS/dBzXaHOgb2gR8NWlTrnSbb607yDipz8V6BfE WVNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792646262; x=1793251062; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=kNAQ43P7mOXqvjFIm1UIgh+LHBg4TUD3j/lYh+CFxWo=; b=lJqAmgeGjxRiNnP8pWiWGWb4Qft5Rxje1BlXNnm0E1UxtEiObBEJfbPGE2wWdZNV7p 9ILVRkN6hjRZSAWotQgzo6dTeqj4UC97wxqkEqYU5m1cZKNtLQELzMZCBlHc0X/uKtCn vyKH8i/+SKHoUMGEgMztgmrnSlsw4ssn4yAhiYhbA/NPaR8MVrwkbfn63Cd4b+nealcI tnxC2rNTnu+zQVvNsHuziwzfF10+C77jU2ECOmkB6AFQNe4HYb2Eo1AIUmflYsOoa7It yJMZs5N1MMHdRyRmdPYqXPKqzqwVAP7n0erFCCDonWOWb5feVgA4c1PIso0eW5VnTXU4 N00w== X-Forwarded-Encrypted: i=1; AKwUvBwSaFD4H17bWIcOTmHr5VUjd4eNevDl8ECip82+PjRqloIJYqhWORBF7JNonj0xAGdQlxB70Upk0ZU=@vger.kernel.org X-Gm-Message-State: AFq9FYLOA7ThTbOPIZKamiTvsclAscL3AEsuW3hN7Dl+H11cJKc7sDuy Cf0eYXQi7eNYw9LsMxHTF8OjZC/Fmicdyr5WEBwudze+Gk1wXlQWnjJo X-Gm-Gg: AYBFou0SYi1LCVfLkkHBMjRXPQQOmIsaRftpDYM4B0gDvuU/Se796VkSHXf1RLP8P3O jAlamXFbem2sPlvE8RSN8UIM23smK3Aevnkm3Zm0xOqjKjFoEFZDnHz+3rXOWKcJS6+Ofu4SroR wYFzhV274Utbco1o/e7FDD0fPu9l+Yb8fl8WmOdWuLj+/HQwdDCBNVVxqIievuZG9U38Pf59Nlv o9S383gdjYuiACrNl2VpKLJfEenfRACT4dimKgqfvBrcQSRwSFG3bdwpALRpzNeCYFN+IkX3fZo r7k85swKyYT9U+PUC4AGIVdmB1KvhODqHKVUcSELRu8DYBeWyWeASntALcFNa+ypfBNni47Hetb mKj5qiMXrD1r12Q9DUKNkHIaQWXTBkc2ssNsIBAgTXzDELa2hupxdraIQHqC3KVmAQujxNfSldv m8lOzCKVLtDqbZpZGPcjYnGS33QIJI4Nxhxe85eCFOzdCXNBisSBodu6+YQQVkBJDho4hySwMqT fA/3ApAJAT0njh3RQHuEjozgdZow53u9QNizv8YtrIKSeU4OOGsrpvlnoAyxFzTqXyhyx9ZAG83 zoYcpFzghO0JXtrLa8l/QY5l8S+BUZx52GRnh4VeUGGg4abdDCH6K22/ot9zgMmG0WEPETF0+Z0 Q4AtVuM79hGjGpuckkM4bf+ehWTUvKHmdWQhRhrT7h0MV6tM5mmPh75rr7k23Y3tQ2+gWUaHA+m lAV6oifQ== X-Received: by 2002:a05:600c:8b4c:b0:4a2:729:f7ce with SMTP id 5b1f17b1804b1-4a20729f92bmr16486165e9.8.1792646261504; Wed, 21 Oct 2026 22:17:41 -0700 (PDT) Received: from localhost.localdomain (dynamic-2a02-3100-ad43-d501-2c28-bb72-120d-420e.310.pool.telefonica.de. [2a02:3100:ad43:d501:2c28:bb72:120d:420e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a1fd0f4427sm90362275e9.3.2026.10.21.22.17.38 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 21 Oct 2026 22:17:41 -0700 (PDT) From: Karl Mehltretter To: Steven Rostedt , Peter Zijlstra , Thomas Gleixner Cc: Karl Mehltretter , Catalin Marinas , Will Deacon , Mark Rutland , Ingo Molnar , Andy Lutomirski , Frederic Weisbecker , "Paul E . McKenney" , Sebastian Andrzej Siewior , Boqun Feng , Waiman Long , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Hongyan Xia , Jonathan Corbet , Shuah Khan , Randy Dunlap , Andrew Morton , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-arm-kernel@lists.infradead.org, linux-trace-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-doc@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC PATCH 09/12] arm64: Use the pre-counted hardirq lifecycle Date: Thu, 22 Oct 2026 07:16:51 +0200 Message-Id: <20261022051654.79224-10-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20261022051654.79224-1-kmehltretter@gmail.com> References: <20261022051654.79224-1-kmehltretter@gmail.com> X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Ordinary EL0 and EL1 interrupt paths establish generic entry state before irq_enter_rcu() adds HARDIRQ_OFFSET and lockdep nesting. Callbacks in that early window are therefore not classified as hardirq work. Their exit paths also drop the classification before function-graph return callbacks and the kernel return tail have completed. After the EL1 pseudo-NMI decision, enter ordinary interrupts through irqentry_hardirq_enter(). Complete delayed timer and accounting work with irq_enter_rcu_preempt_counted(). Use the retained exit preparation followed immediately by raw count and lockdep teardown. For kernel returns, restore return-tail classification after masking DAIF and before MTE exit tracing. Keep the pseudo-NMI lifecycle unchanged. Force arm64 preempt_count() inline so noinstr callers cannot be outlined into instrumentable text. The noinstr path also depends on the raw preempt-count and __kern_my_cpu_offset() inlining changes carried as patches 1 and 2. Keep them separate because they are externally authored fixes. Link: https://lore.kernel.org/all/c3a90368dd6c096af9d918e036a27728696fb8a4.1786603168.git.hongyan.xia@transsion.com/ Link: https://lore.kernel.org/r/20260918161407.2300-12-will@kernel.org Assisted-by: LLM --- arch/arm64/include/asm/preempt.h | 2 +- arch/arm64/kernel/entry-common.c | 23 +++++++++++++++++------ 2 files changed, 18 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h index 4f917596f387d..3d61be0f825fb 100644 --- a/arch/arm64/include/asm/preempt.h +++ b/arch/arm64/include/asm/preempt.h @@ -7,7 +7,7 @@ #define PREEMPT_NEED_RESCHED BIT(32) #define PREEMPT_ENABLED (PREEMPT_NEED_RESCHED) -static inline int preempt_count(void) +static __always_inline int preempt_count(void) { return READ_ONCE(current_thread_info()->preempt.count); } diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 93056a766fb20..fda807c61ff27 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -56,6 +56,8 @@ static void noinstr __arm64_exit_to_kernel_mode(struct pt_regs *regs, irqentry_state_t state) { local_daif_mask(); + /* arm64 uses the split exit API, so enter the tail before MTE tracing. */ + irqentry_hardirq_tail_enter(state); mte_check_tfsr_exit(); irqentry_exit_to_kernel_mode_after_preempt(regs, state); } @@ -523,12 +525,16 @@ static __always_inline void __el1_irq(struct pt_regs *regs, void (*handler)(struct pt_regs *)) { irqentry_state_t state; + bool do_sub; - state = arm64_enter_from_kernel_mode(regs); + state = irqentry_hardirq_enter(regs); + mte_check_tfsr_entry(); + mte_disable_tco_entry(current); - irq_enter_rcu(); + irq_enter_rcu_preempt_counted(); do_interrupt_handler(regs, handler); - irq_exit_rcu(); + do_sub = irq_exit_rcu_preempt_counted_prepare(); + irqentry_hardirq_exit_finish(do_sub); arm64_exit_to_kernel_mode_preempt(regs, state); } @@ -839,16 +845,21 @@ asmlinkage void noinstr el0t_64_sync_handler(struct pt_regs *regs) static void noinstr el0_interrupt(struct pt_regs *regs, void (*handler)(struct pt_regs *)) { - arm64_enter_from_user_mode(regs); + bool do_sub; + + (void)irqentry_hardirq_enter(regs); + mte_disable_tco_entry(current); + sme_enter_from_user_mode(); write_sysreg(DAIF_PROCCTX_NOIRQ, daif); if (regs->pc & BIT(55)) arm64_apply_bp_hardening(); - irq_enter_rcu(); + irq_enter_rcu_preempt_counted(); do_interrupt_handler(regs, handler); - irq_exit_rcu(); + do_sub = irq_exit_rcu_preempt_counted_prepare(); + irqentry_hardirq_exit_finish(do_sub); arm64_exit_to_user_mode(regs); } -- 2.39.5 (Apple Git-154)