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 086E1D2A55F for ; Thu, 4 Dec 2025 22:18:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6634B6B00B4; Thu, 4 Dec 2025 17:17:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 641F06B00B5; Thu, 4 Dec 2025 17:17:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5523B6B00CA; Thu, 4 Dec 2025 17:17:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 44A5F6B00B4 for ; Thu, 4 Dec 2025 17:17:59 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id EBBA513A115 for ; Thu, 4 Dec 2025 22:17:58 +0000 (UTC) X-FDA: 84183202236.28.A0CECE8 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf27.hostedemail.com (Postfix) with ESMTP id 4EF3040014 for ; Thu, 4 Dec 2025 22:17:57 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=pOEb2Ri0; spf=none (imf27.hostedemail.com: domain of rdunlap@infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=rdunlap@infradead.org; dmarc=pass (policy=none) header.from=infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764886677; 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=k6QVH/SWdP5H8bXIHeIZZPkQwVxQdNZJmtX24mN9i90=; b=Jc83Js1zU9qY5utaKqgvhEFFIo6cgi4dS0s/H9xTAgOmbtIpdYuk55Fm4yAoyVf/lyzYeT Ann1FP9HEdpMWTzE7EkxAgiFtmMDVcP+AI5CReBrPfbVLBkRFaqwTUQBfciNmZQ4IGkqFm e0nuB/Z186K1TJCLiQW4CSLsD5p//sY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764886677; a=rsa-sha256; cv=none; b=Yu9Tw5NB71/xxHSFncFCtgh6ZtdjfHh8l0Nyg+XbPI4ZUgWRw4zFpa+EC4t/w36kyrag2+ zPFVdsvkMSCLFpIU9wU/N7W2Jnch9OUvckUbcJBCN+X5mqf9MfQGuIpQtxSFd5kw1C2wLN EuuhfBAYhYOOhmVi+4/v8zA/ZOpz69I= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=pOEb2Ri0; spf=none (imf27.hostedemail.com: domain of rdunlap@infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=rdunlap@infradead.org; dmarc=pass (policy=none) header.from=infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=k6QVH/SWdP5H8bXIHeIZZPkQwVxQdNZJmtX24mN9i90=; b=pOEb2Ri0+biaDj8R76FKt8db8+ gNL4On3s42n2VRZLuJ70zlejVBo2mDgEk/EYYRx/Yt6E52rWb2buoeFpKyiPguCD0G5syhjXcXBeU ze8d4CiTnMu2hAUWOfHD86DLXyVg/QKtpmBx4m0/vbRsPbjLQpe1akjW3F7V2zP6njlBxdpOguU4j 0FcrSKxHcCoKKFK4udrdX7Rn0v/C5CI+Z+ck3F3guEDNZ8VW0MRBqjbP2vKfZa5ixuhKpyMsGsRBk Ut7N2ENViN/YTYVaQce/7brCDDoNtk5mhj0U25jHEnkusKsVLvJxUrtBZEPmPok1jgN5WvqEg5/PM hiEYREbA==; Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRHdh-00000008ihQ-23Ud; Thu, 04 Dec 2025 22:17:31 +0000 Message-ID: Date: Thu, 4 Dec 2025 14:17:27 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v24 25/28] riscv: create a config for shadow stack and landing pad instr support To: Deepak Gupta , 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 , Andreas Korb , Valentin Haudiquet References: <20251204-v5_user_cfi_series-v24-0-ada7a3ba14dc@rivosinc.com> <20251204-v5_user_cfi_series-v24-25-ada7a3ba14dc@rivosinc.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20251204-v5_user_cfi_series-v24-25-ada7a3ba14dc@rivosinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 4EF3040014 X-Stat-Signature: cw3s1wpnbgta18midiie3pc6fm4ywn1d X-Rspam-User: X-HE-Tag: 1764886677-121579 X-HE-Meta: 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 n8q3CzjM 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 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: On 12/4/25 12:04 PM, Deepak Gupta wrote: > This patch creates a config for shadow stack support and landing pad instr > support. Shadow stack support and landing instr support can be enabled by > selecting `CONFIG_RISCV_USER_CFI`. Selecting `CONFIG_RISCV_USER_CFI` wires > up path to enumerate CPU support and if cpu support exists, kernel will > support cpu assisted user mode cfi. > > If CONFIG_RISCV_USER_CFI is selected, select `ARCH_USES_HIGH_VMA_FLAGS`, > `ARCH_HAS_USER_SHADOW_STACK` and DYNAMIC_SIGFRAME for riscv. > > Reviewed-by: Zong Li > Tested-by: Andreas Korb > Tested-by: Valentin Haudiquet > Signed-off-by: Deepak Gupta > --- > arch/riscv/Kconfig | 22 ++++++++++++++++++++++ > arch/riscv/configs/hardening.config | 4 ++++ > 2 files changed, 26 insertions(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 0c6038dc5dfd..f5574c6f66d8 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -1146,6 +1146,28 @@ config RANDOMIZE_BASE > > If unsure, say N. > > +config RISCV_USER_CFI > + def_bool y > + bool "riscv userspace control flow integrity" > + depends on 64BIT && \ > + $(cc-option,-mabi=lp64 -march=rv64ima_zicfiss_zicfilp -fcf-protection=full) > + depends on RISCV_ALTERNATIVE > + select RISCV_SBI > + select ARCH_HAS_USER_SHADOW_STACK > + select ARCH_USES_HIGH_VMA_FLAGS > + select DYNAMIC_SIGFRAME > + help > + Provides CPU assisted control flow integrity to userspace tasks. CPU-assisted > + Control flow integrity is provided by implementing shadow stack for > + backward edge and indirect branch tracking for forward edge in program. > + Shadow stack protection is a hardware feature that detects function > + return address corruption. This helps mitigate ROP attacks. > + Indirect branch tracking enforces that all indirect branches must land > + on a landing pad instruction else CPU will fault. This mitigates against > + JOP / COP attacks. Applications must be enabled to use it, and old user- > + space does not get protection "for free". > + default y. Default is y if hardware supports it. ? > + > endmenu # "Kernel features" -- ~Randy