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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 878FDCEDDA3 for ; Thu, 10 Oct 2024 00:02:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=G7vxyzhNDeqbTyhr5ME76C678/wbdBCiw5i+pKr1cQs=; b=ZnHxuWTz6P0xQp+k222ZXrQOb8 B4seGaU72hl1D1BMrbZbh69pxpdUiv6RNIoYcc6+ElDVvxHkdaf6TGgjLrseL/xSwh11OpjudgD8M 46Z9IE9iIzgaVRaueMiD3M5uHYOTV235rxNn5Wh1UR0BNIY/9NmBuf98DOb1Kt/86DqyCB5A5N2eA srXKcDgMD3/j3Gb0cFrO94UySt0001Iqz1Mw4vTr5zZxloaI5XYQqZN5tGzstHgUdk3tauOptqKpZ ++RgqvMfqz/hKBxzoFQXLNQKkqF1pbOk1HoREbXQzTroNmMXDXfbpq5B78YzK4WL0eh8C3vKMf8bM 8cSyfAsQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sygdG-0000000B5bZ-0yrL; Thu, 10 Oct 2024 00:02:18 +0000 Received: from mail-pj1-x102b.google.com ([2607:f8b0:4864:20::102b]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sygdC-0000000B5ak-2z86 for linux-riscv@lists.infradead.org; Thu, 10 Oct 2024 00:02:16 +0000 Received: by mail-pj1-x102b.google.com with SMTP id 98e67ed59e1d1-2e221a7e7baso292663a91.0 for ; Wed, 09 Oct 2024 17:02:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1728518533; x=1729123333; darn=lists.infradead.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=z81onnv7XmpsFKJJEJouk5fW7lC/eJB47z6sozvRnOU=; b=EQQK085ma4ZlZuxVEqey5bGEdfjPFFbbAPHJrl+rshW3c0vm9+y09L9msP+9mQCJqB n0throZZrkWkbckrsAQMB3rlWPsEDkecBZO/k+Zbvzx2zXswua+67wyBZpN4Ax47qmzj gOevKHym+TX9JZAJ3bi3trojbkS8e2vW9j23jkY6BfbEFhCEpf077PxUNnkhEQHXVJSP +usBFx7WYXBzIf1L88/wJv+NlaNSJiz3QlPklJRXLVMvioIOFDmiKNwkLiq7wh5C7zFj rtAL98nKFt7FWgIs06phGNyBzR9PdbjLAJdo+KNcnLJy4e9+qDm4d4AfjgSKJ+Kyb30E TpBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728518533; x=1729123333; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=z81onnv7XmpsFKJJEJouk5fW7lC/eJB47z6sozvRnOU=; b=pEp8/tdfLLA+c3wYeO5rZF8g+vtjQv4SEKxEzWCxNyNfCo7+k5266nf2IBXXYuE54A oSuhISSUOvCioBdK4f+uevEm59CTcOlxlqszv6B2JYRzYtZuqbdLRWpnt/D9aa/TggTn hZGGiLy9d1Durrl2nyJRmjFaSUqe33iJJTtqu9bEoJoT74Rb8WI7XSMd0O75fxKKtW6A xUp8A5oJStr49DGCdoKUMolP/PVZuaN7Q5LPYPYamj6YAHDa9AUM1ZsLQqWD5ivTXhGw toiQ6ERjviVSaL84EzBFEw+pFqqMEuzLiB/r930N5PSB6CmHwCCN+Ww98dRORvZ60o33 4f/g== X-Forwarded-Encrypted: i=1; AJvYcCWoQt8gDHstFUKxRkfp0ctsAjr1mCR4CMMtkn38wZ+DIh9gpv/6M8NruFeE06i4WmJlISD7IGMT4Ldnow==@lists.infradead.org X-Gm-Message-State: AOJu0YwDWdfvhmSpwtXukRbLJHng+rIn7s5Z+nsB/K3pd8tzxEnXxKOK P+gWDxjnRZ/8/wTUE6vzU3sdVSuf+T3kUzlBv/Z5g40vZ+74BA5ngs47xqpJ3cI= X-Google-Smtp-Source: AGHT+IFZmP54aZT+PGhT0sMeks15kfczHLhKUFL1tfOl/r4KWZKd9Mj0XsQpQ7yVRv3lx6isgmniRg== X-Received: by 2002:a17:90b:4a42:b0:2e2:bad2:69ba with SMTP id 98e67ed59e1d1-2e2bad26afcmr3003723a91.14.1728518533102; Wed, 09 Oct 2024 17:02:13 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e2d5f0b03bsm22252a91.34.2024.10.09.17.02.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Oct 2024 17:02:12 -0700 (PDT) Date: Wed, 9 Oct 2024 17:02:08 -0700 From: Deepak Gupta To: Lorenzo Stoakes Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , 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 , 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 Subject: Re: [PATCH v6 11/33] riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE Message-ID: References: <20241008-v5_user_cfi_series-v6-0-60d9fe073f37@rivosinc.com> <20241008-v5_user_cfi_series-v6-11-60d9fe073f37@rivosinc.com> <22972e7b-0844-4ebc-8d82-a0838b83c3a0@lucifer.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <22972e7b-0844-4ebc-8d82-a0838b83c3a0@lucifer.local> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241009_170214_777888_420F74BC X-CRM114-Status: GOOD ( 22.56 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Oct 09, 2024 at 02:36:12PM +0100, Lorenzo Stoakes wrote: >On Tue, Oct 08, 2024 at 03:36:53PM -0700, Deepak Gupta wrote: >> `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(-) >> >> 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 e79f15293492..4948a1f18ae8 100644 >> --- a/arch/riscv/include/asm/pgtable.h >> +++ b/arch/riscv/include/asm/pgtable.h >> @@ -177,6 +177,7 @@ 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 0e8c20adcd98..964810aeb405 100644 >> --- a/arch/riscv/mm/init.c >> +++ b/arch/riscv/mm/init.c >> @@ -326,7 +326,7 @@ 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 dd4b35a25aeb..b56f1e8cbfc6 100644 >> --- a/mm/mmap.c >> +++ b/mm/mmap.c >> @@ -47,6 +47,7 @@ >> #include >> #include >> #include >> +#include > >This seems benign enough, just wonder why you need it? I think leftover from previous versions. Will remove it. Don't think its needed here anymore. > >> >> #include >> #include >> >> -- >> 2.45.0 >> _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv