From patchwork Thu Sep 12 23:16:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepak Gupta X-Patchwork-Id: 828453 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) (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 D7B2D1CA6A9 for ; Thu, 12 Sep 2024 23:17:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.53 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726183076; cv=none; b=SSvzUT2g4BqdYsTAFu5xJSUo/MRbgiJaN5QkbhtBCw6xELyKImPH9km1aozEjdVQ/grg04MFdPj/dmdY+CrE6zrBRwwjQQlr4vNPgNnDzEl2utgBBwWH5TibR99V7tRZ0Wrb/nRlbL8oAPRMH5MgDBA6QPQCXJFn6cBtFAwvj/w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726183076; c=relaxed/simple; bh=EHU+93eBzQNZszHkkLULrtx7hZG3HFcTa50zagBvcq8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o2YvCePKpf0y6f8CNDSb2at4HFsotbV5TE83lFK3yX0SpTy47ORsln+ScnPKOR0iMzdqCYFLImhkKPMZRiyFX3x+ibSEwPVhoNmGYqLJWD/znja9B73rQHssVStrtD2mwzxhVa4aW9xRx7IrIegy7wiQDxDxll+uqihlM6fkx/U= 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=dP07W/AC; arc=none smtp.client-ip=209.85.216.53 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="dP07W/AC" Received: by mail-pj1-f53.google.com with SMTP id 98e67ed59e1d1-2d8815ef6d2so1276824a91.0 for ; Thu, 12 Sep 2024 16:17:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1726183074; x=1726787874; 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=eiprnGA2BOGVGzJqIZ9S6uz8auKceb/MWPdqRC4IaOM=; b=dP07W/ACmZ4LEK74Bxj79Z2SEdjo218R0pFGbGgipsippIWYUfT3/PO8W5LxzsSjXp C+OkE9WOCml4mTLmWNuvH92nUdgstppfAV6ocjd4hDgnlAyq9Ac053qeRwTOegSYNM1N EX3B5pe4eNjOL9qb94Iz37+LxGtjj0QsMUsoHRSchk9GMrZHjp0idZCjrQojWNbIPBzT cJf+BFJ79uOrTVzwfRwAMMuJZTR4TXT0OgXrmCMu/JfaNjAgBfuEfL+a98EdBoRbLmV7 bq74DZ4jW6Okxg5j4OPD1XU6+6EZjjsm8aipmXPjzQIfuSTPjqvG0VJm50b2FXoWHYsu gTgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726183074; x=1726787874; 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=eiprnGA2BOGVGzJqIZ9S6uz8auKceb/MWPdqRC4IaOM=; b=PNF25QVaXYhlGLKBufz5A3wC5tyU6n/1w4jCcnrYzCjvn+YXB0SB79KcSL8bhHpmET lxkvGPsAg0fxR8PCRxGxlKGGw1KT3fa6ArxW5LoGtzmOlvnN+aAE14g10Am6orrtS893 mlQb20/+2ETdvn7IJ8psCMyF0fjs34kXuFCLqi4falSGWYLmq8uYe3JEe6UA8+UWUIVG kotWI3avtiS1luytBUBeBHtDT2Li6nRlFTuFthbjCEALC0pT3+untRTy8ETtncnaijUa w4l8icJNCe9j4Tx94o/17nVMDXPJ9NTs9whLLWsetuVampo3VByuASPJXQI0BH4jv1bd KQnQ== X-Forwarded-Encrypted: i=1; AJvYcCUY5lcSnRRK5GD00cAcw9GQ92etwVLjlEvL14X/UyKRwfLsjyShAd9R9TK4ooxHoQnII57Qa1i5lBn+ODOomMk=@vger.kernel.org X-Gm-Message-State: AOJu0YxXgIbDRx/hweLnXf4KTER572w6zUtWRyuezYQGs88xHTppTfag NuBoFGUUwcTtsK2GHWsMtuQG392I5eUK2qv9HCNhEENf7KL5k6bIAnntbKgOzpc= X-Google-Smtp-Source: AGHT+IEnJrdTR1Y5qPMoOCKu4YCibaPdfaIv67ki6aFPE+yQ7lsYshwSwmMRsNa90sGyf+0sNSEfcA== X-Received: by 2002:a17:90a:8a13:b0:2da:bd08:edc2 with SMTP id 98e67ed59e1d1-2db9ffcaaaamr5258868a91.9.1726183074122; Thu, 12 Sep 2024 16:17:54 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2db6c1ac69asm3157591a91.0.2024.09.12.16.17.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Sep 2024 16:17:53 -0700 (PDT) From: Deepak Gupta To: paul.walmsley@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-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: corbet@lwn.net, palmer@dabbelt.com, aou@eecs.berkeley.edu, robh@kernel.org, krzk+dt@kernel.org, oleg@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, peterz@infradead.org, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, kees@kernel.org, Liam.Howlett@oracle.com, vbabka@suse.cz, lorenzo.stoakes@oracle.com, shuah@kernel.org, brauner@kernel.org, samuel.holland@sifive.com, debug@rivosinc.com, andy.chiu@sifive.com, jerry.shih@sifive.com, greentime.hu@sifive.com, charlie@rivosinc.com, evan@rivosinc.com, cleger@rivosinc.com, xiao.w.wang@intel.com, ajones@ventanamicro.com, anup@brainfault.org, mchitale@ventanamicro.com, atishp@rivosinc.com, sameo@rivosinc.com, bjorn@rivosinc.com, alexghiti@rivosinc.com, david@redhat.com, libang.li@antgroup.com, jszhang@kernel.org, leobras@redhat.com, guoren@kernel.org, samitolvanen@google.com, songshuaishuai@tinylab.org, costa.shul@redhat.com, bhe@redhat.com, zong.li@sifive.com, puranjay@kernel.org, namcaov@gmail.com, antonb@tenstorrent.com, sorear@fastmail.com, quic_bjorande@quicinc.com, ancientmodern4@gmail.com, ben.dooks@codethink.co.uk, quic_zhonhan@quicinc.com, cuiyunhui@bytedance.com, yang.lee@linux.alibaba.com, ke.zhao@shingroup.cn, sunilvl@ventanamicro.com, tanzhasanwork@gmail.com, schwab@suse.de, dawei.li@shingroup.cn, rppt@kernel.org, willy@infradead.org, usama.anjum@collabora.com, osalvador@suse.de, ryan.roberts@arm.com, andrii@kernel.org, alx@kernel.org, catalin.marinas@arm.com, broonie@kernel.org, revest@chromium.org, bgray@linux.ibm.com, deller@gmx.de, zev@bewilderbeest.net Subject: [PATCH v4 11/30] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Date: Thu, 12 Sep 2024 16:16:30 -0700 Message-ID: <20240912231650.3740732-12-debug@rivosinc.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240912231650.3740732-1-debug@rivosinc.com> References: <20240912231650.3740732-1-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 | 10 ++++++++++ arch/riscv/mm/init.c | 2 +- mm/mmap.c | 1 + 5 files changed, 37 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 089f3c9f56a3..af4337774fe5 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -181,6 +181,7 @@ 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 d77afe05578f..43a448bf254b 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 eb0649a61b4c..000b51c26943 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -324,7 +324,7 @@ 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 d0dfc85b209b..04023a464fac 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include