From patchwork Fri Mar 29 04:44:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepak Gupta X-Patchwork-Id: 13610028 Received: from mail-pf1-f170.google.com (mail-pf1-f170.google.com [209.85.210.170]) (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 C1B9B40845 for ; Fri, 29 Mar 2024 04:46:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711687578; cv=none; b=NVcgBOeyuLM1Pi6Q424JoefkV22rsRhg1HC1Avk2IoP7yfwtVBcDDggC6u/jDX5VwZL68jdXLAp2+DBzpH0bHWeABzfKtTw4CV4zLIN3G6vql3e994sDMufaJJ27UzilR5ffItYmX5DJHzKnN+4ikKKpgy5aZgG5SQ33NTX1WOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711687578; c=relaxed/simple; bh=k3xGskk+M3dZNxtOtmuZmmKUWDnDnrW+6hd7RkQA5mU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=o5xAd7fEboZ1PRLO5IXCdy2mNkaUkH/qmTLqEVrLRdpm3q2zwWu4CaoiIfz5zDRjG0gEmFcPREsdAw08yUGalmUFovbdnkgNXlZw+Ny3zUWjEw5BFewWDHCxd22aaON8lsgKU6N6Uva/UGmO1q2oV6CmIy31bXUnfLbgDPAwr8Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com; spf=pass smtp.mailfrom=rivosinc.com; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b=eFB+HMwA; arc=none smtp.client-ip=209.85.210.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="eFB+HMwA" Received: by mail-pf1-f170.google.com with SMTP id d2e1a72fcca58-6e6b6f86975so1123636b3a.1 for ; Thu, 28 Mar 2024 21:46:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1711687576; x=1712292376; 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; bh=pODlhOn2Qlpzyvoy16i8OpTFZF278Z1sqN5yeQeAUQM=; b=eFB+HMwAOfJrV+eJ1S12u6R3ktPG+FiEi2rcW6NcDPC2lopPwdIgfQfsdxJgjYruQF jyqLkzoai3Vmk60xM74Wn3EsqxRn+GdZO8dM5sPWsXquiU1RIKCOoKGKd1FGAPAMsJHZ zbomgEH4Kn0oFwjUlxY9WhMEcE7Im3fDfbeNevAsLgBHxaxBfmJLK0RjYMySOwHTgDwE kXIQw0j0srK6Ao6dGQ0Oz6yXHLMmUhDyBFCOtZEiK2/I58p74ZXAsMdW9Uyg9cZBO28W 5HGRHz463U/KpwHKlX/ONFHN6vt2bdUz0wAN7DSgqGpZsozyfnHRKrJoRkeDK0gg40aG pTSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711687576; x=1712292376; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=pODlhOn2Qlpzyvoy16i8OpTFZF278Z1sqN5yeQeAUQM=; b=bfIPx7IJAFSnEc9DqosW+QO+qDN/cn+Fmbbd6+QYDSbtXwTs1UwBkgFTVPsflqRA1I TC/+GKFBwVOu/d/InGSq6ZLp+miYyVC2fUbsHiglV8XNUjWp5H96MQQbeoocrg3n3vdS 2qyEsB9Qb8Ms4CHHXnf69A3sg7MFAf38401ukRGiNWePqjYKhjmiEG8n3Q9yCtXa0zQC 4GBUdbH5wGxDeF1XjD7wZ6o228KUvqk4ciuiA1evev8r38ntMbNsnNCJVxuPYJoiTrFG /QkD4FttuymoHc2H9XR5UOdOChO/y9vO0ZUT9cuUINgoegABJVASYGsp31H6eLVGELZi hI1g== X-Forwarded-Encrypted: i=1; AJvYcCVeA/Q7IUkKnwgckF6U01h3mqz+RlP4TBZ3TtdHJc4sSYzoks6LZGhWHBo3IbdtSYg3N4Mt2x4FuCosAJKS21L4t7o7NdgMo++bjGGWsGHR X-Gm-Message-State: AOJu0YySxwKzAvD4pYOhrhWT+/Ku2CvnRTMiMfBxHjvpkxu59+UxkBdf lZGEeHkzuhWrzyZHFriqpIrvDzltVOzylQF5jXyLR8xEsvhai/QhTlFoZR3AIs4= X-Google-Smtp-Source: AGHT+IEEpy9pSrtr+BvW+AqTbkR2NWQ8ISKhZnwm1fAksXWCTeDRwW/aV3jv7PvAv025C+VRS8TIYg== X-Received: by 2002:a05:6a00:3ccb:b0:6ea:74d4:a01c with SMTP id ln11-20020a056a003ccb00b006ea74d4a01cmr1489683pfb.14.1711687576218; Thu, 28 Mar 2024 21:46:16 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id i18-20020aa78b52000000b006ea7e972947sm2217120pfd.130.2024.03.28.21.46.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Mar 2024 21:46:15 -0700 (PDT) From: Deepak Gupta To: paul.walmsley@sifive.com, rick.p.edgecombe@intel.com, broonie@kernel.org, Szabolcs.Nagy@arm.com, kito.cheng@sifive.com, keescook@chromium.org, ajones@ventanamicro.com, conor.dooley@microchip.com, cleger@rivosinc.com, atishp@atishpatra.org, alex@ghiti.fr, bjorn@rivosinc.com, alexghiti@rivosinc.com, samuel.holland@sifive.com, palmer@sifive.com, conor@kernel.org, linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: corbet@lwn.net, tech-j-ext@lists.risc-v.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, oleg@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, Liam.Howlett@oracle.com, vbabka@suse.cz, lstoakes@gmail.com, shuah@kernel.org, brauner@kernel.org, debug@rivosinc.com, andy.chiu@sifive.com, jerry.shih@sifive.com, hankuan.chen@sifive.com, greentime.hu@sifive.com, evan@rivosinc.com, xiao.w.wang@intel.com, charlie@rivosinc.com, apatel@ventanamicro.com, mchitale@ventanamicro.com, dbarboza@ventanamicro.com, sameo@rivosinc.com, shikemeng@huaweicloud.com, willy@infradead.org, vincent.chen@sifive.com, guoren@kernel.org, samitolvanen@google.com, songshuaishuai@tinylab.org, gerg@kernel.org, heiko@sntech.de, bhe@redhat.com, jeeheng.sia@starfivetech.com, cyy@cyyself.name, maskray@google.com, ancientmodern4@gmail.com, mathis.salmen@matsal.de, cuiyunhui@bytedance.com, bgray@linux.ibm.com, mpe@ellerman.id.au, baruch@tkos.co.il, alx@kernel.org, david@redhat.com, catalin.marinas@arm.com, revest@chromium.org, josh@joshtriplett.org, shr@devkernel.io, deller@gmx.de, omosnace@redhat.com, ojeda@kernel.org, jhubbard@nvidia.com Subject: [PATCH v2 09/27] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Date: Thu, 28 Mar 2024 21:44:41 -0700 Message-Id: <20240329044459.3990638-10-debug@rivosinc.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240329044459.3990638-1-debug@rivosinc.com> References: <20240329044459.3990638-1-debug@rivosinc.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 `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. Signed-off-by: Deepak Gupta --- arch/riscv/include/asm/mman.h | 24 ++++++++++++++++++++++++ arch/riscv/include/asm/pgtable.h | 1 + arch/riscv/kernel/sys_riscv.c | 11 +++++++++++ arch/riscv/mm/init.c | 2 +- mm/mmap.c | 1 + 5 files changed, 38 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/include/asm/mman.h diff --git a/arch/riscv/include/asm/mman.h b/arch/riscv/include/asm/mman.h new file mode 100644 index 000000000000..ef9fedf32546 --- /dev/null +++ b/arch/riscv/include/asm/mman.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#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 6066822e7396..4d5983bc6766 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -184,6 +184,7 @@ extern struct pt_alloc_ops pt_ops __initdata; #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 f1c1416a9f1e..846c36b1b3d5 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -8,6 +8,8 @@ #include #include #include +#include +#include static long riscv_sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, @@ -17,6 +19,15 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) return -EINVAL; + /* + * If only 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 fa34cf55037b..98e5ece4052a 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -299,7 +299,7 @@ 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, diff --git a/mm/mmap.c b/mm/mmap.c index d89770eaab6b..57a974f49b00 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include