From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0610CCD1AB for ; Wed, 22 Oct 2025 23:29:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0B5418E000C; Wed, 22 Oct 2025 19:29:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 066658E0002; Wed, 22 Oct 2025 19:29:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E48A38E000C; Wed, 22 Oct 2025 19:29:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id D09A18E0002 for ; Wed, 22 Oct 2025 19:29:53 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A1A12129826 for ; Wed, 22 Oct 2025 23:29:53 +0000 (UTC) X-FDA: 84027345066.24.BA6EB2F Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) by imf21.hostedemail.com (Postfix) with ESMTP id DDEFE1C0004 for ; Wed, 22 Oct 2025 23:29:51 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=rivosinc.com header.s=google header.b=HFesGPpe; dmarc=pass (policy=none) header.from=rivosinc.com; spf=pass (imf21.hostedemail.com: domain of debug@rivosinc.com designates 209.85.210.169 as permitted sender) smtp.mailfrom=debug@rivosinc.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761175791; a=rsa-sha256; cv=none; b=wjc7X7LJd/yahIyQoc5tnTKrvEXiOB3RnEz1lEzCQTYt4oyeOYUQFOKQTXnefeMvf1hjhs bbgKJK3tA12X563pRkgZ9vWaJZAoDsmoTsY05Hkd1hn/lMk+nmgJYHHF6IXLzkAr09yZZT Amo9Vf/m1iTh3ZmL4NH159p6eNPfQpI= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=rivosinc.com header.s=google header.b=HFesGPpe; dmarc=pass (policy=none) header.from=rivosinc.com; spf=pass (imf21.hostedemail.com: domain of debug@rivosinc.com designates 209.85.210.169 as permitted sender) smtp.mailfrom=debug@rivosinc.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761175791; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7ZlhaeGyn05OIbis6SfSAIFcz6IbZPi7uJh5910jbDw=; b=lRmuL9BJBCLOKEauXn9nWPB+JHTbYGWMffZcmPAAUN3r0jqMCqgfpJfN/dfe96y/hmO/zJ SSiL4P9XTsE0IX8/ttDz8WomFgfwbN/KXJBRdHmpvLf+uUYdnOPs+EYb68laNojgucw8eT FLeLS91h1raHL5kgmT/H7lWtUgC7CAs= Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-781206cce18so161284b3a.0 for ; Wed, 22 Oct 2025 16:29:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc.com; s=google; t=1761175791; x=1761780591; darn=kvack.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=7ZlhaeGyn05OIbis6SfSAIFcz6IbZPi7uJh5910jbDw=; b=HFesGPpe62lNk9YhCV1iOyJ0PuiySSoRZn3moWvQkjnWjfZ8kFTrAWD7dm4McP7W/c vZDnXlkBkgDTHfe/RT3UyvSc7pUaTs6UxnRin/MDL38YEdp5NPrD6vz3EiH/DDGi4owQ y6eSJjzpPV4WBO7YdTwlbqTYmiFBXF1dqYtwHC/DY9zPadn1qK9ad/yAj1MLOVCfLUGT OuUKpU0oZvrIHOfxbmmAagk0ZY8JQc+pX/54OrsY34+WFDeeBoC9HUyurRF52+NVu5vZ AqWHRd8E96Gr8mLDTz0wGUR909K7L7ioHLpwpMJUIwF5BFEHI4CG+dKchGWNvP+fLfDv IAXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761175791; x=1761780591; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=7ZlhaeGyn05OIbis6SfSAIFcz6IbZPi7uJh5910jbDw=; b=A+9o+2AtQWgj0t3Q0aYUNw4ASO51+IsXNjTTWDDJHQ7kG+99UJasIqPmWI7eFcEz8g ZqtK4X5nMv5hYe3V9AHnBB7cFbqwXC0QorSAkmCA2yhZroSoSre1EzvZ8c+cVk7zVb0k CDVYO9zTK0m0cLcGJOVRnq0tZEOLQbXrGCSn9807GoTG1+9Q2pgSFKVkP37SfH/7JDaM +uaGNgoppuzAX2b7n3DQ3kdvgQjJABTKepOJWfLKMTXZA0hyUGOY9IJFyy74VvcoYg/Q o//CFFZ2dhFL/XuGMYzjxYpEEk7IVCCiyKJdX/uXSlEiZ2Rr63FOcAITRpr+kFP7LY47 g8Ng== X-Forwarded-Encrypted: i=1; AJvYcCW1U58kHbmrqqD8TY9+B5Y+CL7/MPKdOBXb+mvdu1lOl473/naJSr90fVY3+4LyYD3teESVxqJ/tA==@kvack.org X-Gm-Message-State: AOJu0Yx4a3NFDX2Wqcgf1bIzSGdn1VM1VqqTvk5Kq+wqAzVCS9Fx6MeC SDtLYmay7hcQGNq/eB8FO9Tyk43fFksECVSiwg8LZOKXO8poJPBVtjN+hdYyVD0xIXc= X-Gm-Gg: ASbGncuYYjuE6Teo/MQaeRbvJzcapM2aEk5gh00QYMRqFrupRugHfVw0ryGci3wBIkV 98/2dfPqiipFAq5x0NIN2roKEXeAaR7RywLAxlwHxyubvLUAgTQcq8B+v8hjNy7uJi5UhitOEUV 4rl8r7x0qBFNSrQVn4JhHuQ3TX6lSJRhvTnS5dzrUMSretn3Ub/5KIbbyk2uvnHMBwgtYX9hIHa dHODsNk/HYBiJSg2JQ7DqIfrjx3+AmXGhiXFidoYVoctxERFJQAdwgpcnTgL9lVRY7gXl4fIwCR XpMTSnPMIHqxrA/WsbFz+VyALu1YF4dpYxmglieeHlG/lhrnfNspWh5Ri0jVlGA3vlmL1zrO4Hg i1PJdTDcV3pYjGPNGMcWJ9Exui/YywHjYbjBnuCI2fSjJtsmgBl59l8t2b9jROF4wk1/7BIsGGr yPZTU3Cy+1pw== X-Google-Smtp-Source: AGHT+IG4cbiBVjJNCgBYLEYEdqajOum54aXNq+CrIlTed76CQmY277uQptUVhs68Tc/ubzYSOTYfdg== X-Received: by 2002:a05:6a00:bd11:b0:781:1fa9:151e with SMTP id d2e1a72fcca58-7a2647cb491mr5883654b3a.15.1761175790644; Wed, 22 Oct 2025 16:29:50 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7a274dc12b2sm392646b3a.67.2025.10.22.16.29.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Oct 2025 16:29:50 -0700 (PDT) From: Deepak Gupta Date: Wed, 22 Oct 2025 16:29:32 -0700 Subject: [PATCH v22 06/28] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251022-v5_user_cfi_series-v22-6-fdaa7e4022aa@rivosinc.com> References: <20251022-v5_user_cfi_series-v22-0-fdaa7e4022aa@rivosinc.com> In-Reply-To: <20251022-v5_user_cfi_series-v22-0-fdaa7e4022aa@rivosinc.com> To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Rob Herring , Krzysztof Kozlowski , Arnd Bergmann , Christian Brauner , Peter Zijlstra , Oleg Nesterov , Eric Biederman , Kees Cook , Jonathan Corbet , Shuah Khan , Jann Horn , Conor Dooley , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Benno Lossin Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, alistair.francis@wdc.com, richard.henderson@linaro.org, jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com, charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, alexghiti@rivosinc.com, samitolvanen@google.com, broonie@kernel.org, rick.p.edgecombe@intel.com, rust-for-linux@vger.kernel.org, Zong Li , Deepak Gupta X-Mailer: b4 0.13.0 X-Stat-Signature: 9m8cc3yhu66w3kgyeg1makzoo56jekgk X-Rspamd-Queue-Id: DDEFE1C0004 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1761175791-766023 X-HE-Meta: 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 Wlwjl82r aFQOp6YrMg0Hbxg4RN70XX9d85wshwpHeFlv5KLhsFHqggZJqUgX3DvvOlV5yzwzv7OlubfBI2cw7b3KC/5zrIJ5ABut4xgWbqyGhGiajIxULF1zCOaWhlNjgckhxlm+p8zKDl/BDBiANjEA= 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: `arch_calc_vm_prot_bits` is implemented on risc-v to return VM_READ | VM_WRITE if PROT_WRITE is specified. Similarly `riscv_sys_mmap` is updated to convert all incoming PROT_WRITE to (PROT_WRITE | PROT_READ). This is to make sure that any existing apps using PROT_WRITE still work. Earlier `protection_map[VM_WRITE]` used to pick read-write PTE encodings. Now `protection_map[VM_WRITE]` will always pick PAGE_SHADOWSTACK PTE encodings for shadow stack. Above changes ensure that existing apps continue to work because underneath kernel will be picking `protection_map[VM_WRITE|VM_READ]` PTE encodings. Reviewed-by: Zong Li Reviewed-by: Alexandre Ghiti Signed-off-by: Arnd Bergmann Signed-off-by: Deepak Gupta --- arch/riscv/include/asm/mman.h | 26 ++++++++++++++++++++++++++ arch/riscv/include/asm/pgtable.h | 1 + arch/riscv/kernel/sys_riscv.c | 10 ++++++++++ arch/riscv/mm/init.c | 2 +- 4 files changed, 38 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.h new file mode 100644 index 000000000000..0ad1d19832eb --- /dev/null +++ b/arch/riscv/include/asm/mman.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include +#include +#include +#include + +static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, + unsigned long pkey __always_unused) +{ + unsigned long ret = 0; + + /* + * If PROT_WRITE was specified, force it to VM_READ | VM_WRITE. + * Only VM_WRITE means shadow stack. + */ + if (prot & PROT_WRITE) + ret = (VM_READ | VM_WRITE); + return ret; +} + +#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) + +#endif /* ! __ASM_MMAN_H__ */ diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 29e994a9afb6..4c4057a2550e 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -182,6 +182,7 @@ extern struct pt_alloc_ops pt_ops __meminitdata; #define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) #define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \ _PAGE_EXEC | _PAGE_WRITE) +#define PAGE_SHADOWSTACK __pgprot(_PAGE_BASE | _PAGE_WRITE) #define PAGE_COPY PAGE_READ #define PAGE_COPY_EXEC PAGE_READ_EXEC diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c index 795b2e815ac9..22fc9b3268be 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -7,6 +7,7 @@ #include #include +#include static long riscv_sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, @@ -16,6 +17,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) return -EINVAL; + /* + * If PROT_WRITE is specified then extend that to PROT_READ + * protection_map[VM_WRITE] is now going to select shadow stack encodings. + * So specifying PROT_WRITE actually should select protection_map [VM_WRITE | VM_READ] + * If user wants to create shadow stack then they should use `map_shadow_stack` syscall. + */ + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) + prot |= PROT_READ; + return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - page_shift_offset)); } diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index d85efe74a4b6..62ab2c7de7c8 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -376,7 +376,7 @@ pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); static const pgprot_t protection_map[16] = { [VM_NONE] = PAGE_NONE, [VM_READ] = PAGE_READ, - [VM_WRITE] = PAGE_COPY, + [VM_WRITE] = PAGE_SHADOWSTACK, [VM_WRITE | VM_READ] = PAGE_COPY, [VM_EXEC] = PAGE_EXEC, [VM_EXEC | VM_READ] = PAGE_READ_EXEC, -- 2.43.0