From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D5A435957; Sat, 7 Jun 2025 21:31:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749331890; cv=none; b=uILABHe7F3QH4dipYrczYlbnLlXgFgoI3iQ9MgXVYYPMOAbHAY2vdphwlQgN3i/znnkSBl8rrlIbsKNNrF9xMC7CypjJ3Yo2sGTXZW+XX+Dm/2SCg8c8FYgtPnDhALFq9C2JjfzYdngtloH9XLnLn4y5PpaMs04RtWgESjuGJKc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749331890; c=relaxed/simple; bh=8aIyffKejPWFzUAjtn7mONxd6kcAwOjWhbvLV30cHpA=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=e/3oUEejHrOqXOvaxYrWY09b3wyKgrKyCRnFeCjg3OdJ7GM4FH0eBU6Mv3gt3O99qdhfh2f+h6J7u+Ieftg1A5YPF7lXbwuiZBbSqQrwKZ7pMxZZdSP23vyU5c6L2qdzK4ZKxeEJUOI181/lM21foERuO56rXixp5nGqaj5TkvI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=d5eH7hOk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="d5eH7hOk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61277C4CEE4; Sat, 7 Jun 2025 21:31:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1749331889; bh=8aIyffKejPWFzUAjtn7mONxd6kcAwOjWhbvLV30cHpA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=d5eH7hOkXO+2GLIjd3Zsk5dRCih1mBAwA6gIAZWUaDp3jBv9zX+7ymfH6NeZmoK+1 rzLn9Cn058pWhtneEzEQleuRD3YGNqKkKXOdo7vNhvIqDZO/VqNuK1mHwEMpbBoLIs xNNUz3saTvHrtJIg/s2GE5bOFhwpX3pfmVvRAA/Q= Date: Sat, 7 Jun 2025 14:31:28 -0700 From: Andrew Morton To: wangfushuai Cc: , , , , , , , Mark Brown , Catalin Marinas Subject: Re: [PATCH v2] fs/proc/task_mmu: add VM_SHADOW_STACK for arm64 when support GCS Message-Id: <20250607143128.d3ae86e8ebf9dcab02870421@linux-foundation.org> In-Reply-To: <20250607131525.76746-1-wangfushuai@baidu.com> References: <20250607131525.76746-1-wangfushuai@baidu.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 7 Jun 2025 21:15:25 +0800 wangfushuai wrote: > The recent commit adding VM_SHADOW_STACK for arm64 GCS did not update > the /proc/[pid]/smaps display logic to show the "ss" flag for GCS pages. > This patch adds the necessary condition to display "ss" flag. > > ... > > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -994,6 +994,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) > #ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK > [ilog2(VM_SHADOW_STACK)] = "ss", > #endif > +#if defined(CONFIG_ARM64_GCS) > + [ilog2(VM_SHADOW_STACK)] = "ss", > +#endif > #if defined(CONFIG_64BIT) || defined(CONFIG_PPC32) > [ilog2(VM_DROPPABLE)] = "dp", > #endif It is possible to have CONFIG_ARM64_GCS=y when CONFIG_ARCH_HAS_USER_SHADOW_STACK=n? If so, is this a correct combination? Also, wouldn't it be nicer to code this as --- a/fs/proc/task_mmu.c~a +++ a/fs/proc/task_mmu.c @@ -991,7 +991,7 @@ static void show_smap_vma_flags(struct s #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR [ilog2(VM_UFFD_MINOR)] = "ui", #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ -#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK +#if defined(CONFIG_ARCH_HAS_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS) [ilog2(VM_SHADOW_STACK)] = "ss", #endif #if defined(CONFIG_64BIT) || defined(CONFIG_PPC32) _