From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1DA5E3E00A1 for ; Thu, 27 Aug 2026 23:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787873496; cv=none; b=dcYZC/JsawPgxQoGez3O/lxSmdLObw2sJlaFbhznNtUzQSSsN/q09AeTqSrA92Mc+Wq9YqH+zQZ2tpdNTbRSjLR4gsrLlnxRxgzK+x8Q8OHm68aZbCkCpHLd1Jr0EMm9fcLcL6+nEyVTMsm9Nh0hqzj++055fKEi4GCopvxVeKI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787873496; c=relaxed/simple; bh=IaRhJZseYtmfOAwaHfBsaGhcCpvv3aaACzd/i2DLAGY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=pbIGjmWNOu1qPyQt79/89JkEIQ9X3fAkEY2XUiIVlaf7TI7WjvGvNQKtU9MtWCepGSLKSr2eSYPVclRgLsR3NJOY/rbaSmvlyOarE9cDjeQkmM0fFD9QGAQ4KLR9c2DPiVQawoig3LA4yjk2P2rFAWwAS43LYEJ3XfnV8x1J+jU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--stevensd.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=KlzEJEzK; arc=none smtp.client-ip=209.85.214.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--stevensd.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KlzEJEzK" Received: by mail-pl1-f200.google.com with SMTP id d9443c01a7336-2d55d8cd938so3865005ad.1 for ; Thu, 27 Aug 2026 16:31:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787873494; x=1788478294; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=63v8voqDYPPccdvhHdT2gYF/erUoDbYrARzDm1If6YE=; b=KlzEJEzKZb6/bgpdNjlaIyl1YKIdsfC7GmOVUzpoKjPK+NUY5os4m9evvjfejTfzaD V0cnZa7QpQfpj5SxyJKHm+Zs60GQ2o8qYKVte53iVIo7ZxM5crSQtOYN5279LoxWbOwl Z4VgdWG/v2ZWFPbpHqRq44/KY7d5FhwoCyLBVT/u5frABiloH7jOAk0YbCsuT2yp3KHR kN/Mq8RSZIIVimia4yK3+l1J17puwjKjtmLBD1eDPT8p/jZxcDncqA9c5UiAxHpqvBVP AANXF1WxPjyLRXR/PVdX3ohTuEBdO9PVoIubO5RzZQCeNvSfwZvb5zvm84dKA/Q5CXGl Z9JA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787873494; x=1788478294; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=63v8voqDYPPccdvhHdT2gYF/erUoDbYrARzDm1If6YE=; b=f/YWwNB735YD16lThhwEanDBmsJbtjIatFybGv0jEp6zkbg7YoFQVX0brh56p+fap4 z/t/Txrahf13244iPqtgUuRLcthNwaKhlVdUe1X0CP4qzn5RUu9Eg/9N+zlIeZEmNNIj YzG6ll+QmQ/lYg/jLNj5LcsH55yg4G+Sa/a19iaolRoPQJoiFWYaKpP6R3ejV0p5ghy6 2Gfn3INoWkTcNFW5gMV9B40YxBXDRp58qxHY0/0HoYT3JxIKDdg+GyDJmdWEiuHNY0Dn QfW5NnnlPEGyByshk4oehXimlms81LHbwCp2rEW8mmn143Bv+YTJA+Vp9kfYJyGIDa7R P//Q== X-Forwarded-Encrypted: i=1; AHgh+RrvKTQNMaIH+orvpx5oH47yMHDo3XWvDwcz0H/kfVPF8ogWmR9jF/9ZQKqiW6NbcwSTcq0LSwc3Smm8yYsetA==@lists.linux.dev X-Gm-Message-State: AFuF++lwH/sTem9wV4vfDS/tWwcWuMP0QKYeR2s8MmRs2TfRSUjUC/OM s9o0MlmaUaO0Xo/TH5BG1W/8/1q/G0UPEfNJA9eUlfxMWeUN+rFnXM6MTtxuasyZyXS0+lAANxu 6aoKG2pcfLEg8mg== X-Received: from dybpd7.prod.google.com ([2002:a05:7301:4547:b0:327:dce2:b13c]) (user=stevensd job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1850:b0:2d5:e3ce:3988 with SMTP id d9443c01a7336-2d74dddceebmr49959775ad.11.1787873494176; Thu, 27 Aug 2026 16:31:34 -0700 (PDT) Date: Thu, 27 Aug 2026 16:29:47 -0700 In-Reply-To: <20260827232948.2520558-1-stevensd@google.com> Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260827232948.2520558-1-stevensd@google.com> X-Mailer: git-send-email 2.55.0.897.gb25b4bd76c-goog Message-ID: <20260827232948.2520558-10-stevensd@google.com> Subject: [RFC 09/10] x86: Enable reclaimable stacks From: David Stevens To: Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Andrew Morton , Dave Chinner , Qi Zheng , Roman Gushchin , Muchun Song , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Uladzislau Rezki , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Sebastian Andrzej Siewior , Clark Williams , suleiman@google.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-rt-devel@lists.linux.dev, David Stevens Content-Type: text/plain; charset="UTF-8" Implement top_of_blocked_task_stack() to get the stack pointer out of a thread_struct and enable HAVE_ARCH_RECLAIMABLE_STACK. Signed-off-by: David Stevens --- arch/x86/Kconfig | 1 + arch/x86/include/asm/processor.h | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index bdad90f210e4..652d5a9c0830 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -211,6 +211,7 @@ config X86 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD select HAVE_ARCH_VMAP_STACK if X86_64 + select HAVE_ARCH_RECLAIMABLE_STACK if X86_64 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_WITHIN_STACK_FRAMES select HAVE_ASM_MODVERSIONS diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 87b1d4c0727e..207e7adced64 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -690,6 +690,11 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip, #define GET_TSC_CTL(adr) get_tsc_mode((adr)) #define SET_TSC_CTL(val) set_tsc_mode((val)) +static inline unsigned long top_of_blocked_task_stack(struct thread_struct *thread) +{ + return thread->sp; +} + extern int get_tsc_mode(unsigned long adr); extern int set_tsc_mode(unsigned int val); -- 2.55.0.897.gb25b4bd76c-goog