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Fri, 08 Aug 2025 10:20:21 -0700 (PDT) Date: Fri, 8 Aug 2025 10:20:17 -0700 From: Deepak Gupta To: Mark Brown Cc: patchwork-bot+linux-riscv@kernel.org, linux-riscv@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, akpm@linux-foundation.org, Liam.Howlett@oracle.com, vbabka@suse.cz, lorenzo.stoakes@oracle.com, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, conor@kernel.org, robh@kernel.org, krzk+dt@kernel.org, arnd@arndb.de, brauner@kernel.org, peterz@infradead.org, oleg@redhat.com, ebiederm@xmission.com, kees@kernel.org, corbet@lwn.net, shuah@kernel.org, jannh@google.com, conor+dt@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, lossin@kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.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, rick.p.edgecombe@intel.com, rust-for-linux@vger.kernel.org, zong.li@sifive.com, david@redhat.com Subject: Re: [PATCH v19 00/27] riscv control-flow integrity for usermode Message-ID: References: <20250731-v5_user_cfi_series-v19-0-09b468d7beab@rivosinc.com> <175450053775.2863135.11568399057706626223.git-patchwork-notify@kernel.org> <09081487-89ac-4f8d-b9fc-e563f09726d2@sirena.org.uk> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <09081487-89ac-4f8d-b9fc-e563f09726d2@sirena.org.uk> On Fri, Aug 08, 2025 at 12:48:31PM +0100, Mark Brown wrote: >On Fri, Aug 08, 2025 at 01:23:15AM -0700, Deepak Gupta wrote: >> On Thu, Aug 07, 2025 at 01:28:36PM +0100, Mark Brown wrote: > >> > Do you have an update for my clone3() shadow > >> No I don't. > >> > stack series that I could roll in for when I repost that after the merge >> > window, and/or instructions for how to run this stuff for RISC-V on some >> > emulated platform? > >> I would want to write-up instructions. But I don't want you to go through >> a lot of hassle of building toolchain and bunch of other stuff. >> Let me see how I can make it easy for you. Will report back. > >Thanks. FWIW I should already be sorted for the kernel build, unless >there's a super new or specialist toolchain required for this feature Unlike x86 shadow stack and arm's GCS, push on RISC-V shadow stack is done using dedicated `sspush` instruction and pop is done using instruction `sspopchk`. RISC-V vDSO has certain `C` files and they would need shadow stack push and pop (along with landing pad on them). So that's why kernel compile would require the toolchain. I'll point you to it. >(I'd guess I should be fine for the shadow stacks bit?) - it's userspace >and emulation for the extension I'm missing. Qemu changes are upstream. I'll provide the command line option. On userspace, I'll point you to something pre-compiled rootfs.