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AJvYcCVm4Q0MA1x5Uueoq1UlLBOcoLds6kUleNPoy2BP7bvqXj8n+LXpoibnustXbvR5u4Z0lWtbG2TsZB8hToMbViGKXUaFunHpswRVUw== X-Gm-Message-State: AOJu0Yy6wnVWEcEMYVy33VrpX80t6tx9n+65EjefbFD26Eam0j0QP+XS wcpPoapa7bMHUFKA4AFQljTR9MVFEJ/dXkOouJwBcwAMRNGjT0W081wmhapt1Fw= X-Google-Smtp-Source: AGHT+IFPYkwFkCWA+SA7mff7SB9WJfJBYnvlFHy9eSaPUSq9JIjSJtsLm/B02BDU1sUJv+HfqHd+4Q== X-Received: by 2002:a17:902:f68a:b0:1e2:887a:68a7 with SMTP id l10-20020a170902f68a00b001e2887a68a7mr4103646plg.33.1712266763893; Thu, 04 Apr 2024 14:39:23 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id l10-20020a170903244a00b001e29833ada6sm89367pls.140.2024.04.04.14.39.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Apr 2024 14:39:23 -0700 (PDT) Date: Thu, 4 Apr 2024 14:39:20 -0700 From: Deepak Gupta To: David Hildenbrand Cc: 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, 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, corbet@lwn.net, 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, 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, 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, Mike Rapoport Subject: Re: [PATCH v3 09/29] mm: abstract shadow stack vma behind `vma_is_shadow_stack` Message-ID: References: <20240403234054.2020347-1-debug@rivosinc.com> <20240403234054.2020347-10-debug@rivosinc.com> Precedence: bulk X-Mailing-List: devicetree@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: On Thu, Apr 04, 2024 at 09:02:17PM +0200, David Hildenbrand wrote: >On 04.04.24 01:34, Deepak Gupta wrote: >> } >>- } else if (!(vm_flags & VM_READ)) { >>+ } else if (!(vm_flags & VM_READ) && !vma_is_shadow_stack(vm_flags)) { >>+ /* reads allowed if its shadow stack vma */ >> if (!(gup_flags & FOLL_FORCE)) >> return -EFAULT; >> /* > >Unless I am missing something, this is not a simple cleanup. It should >go into a separate patch with a clearly documented reason for that >change. I tried that here https://lore.kernel.org/linux-mm/CAKC1njTPBqtsAOn-CWhB+-8FaZ2KWkkz-vRZr7MZq=0yLUdjcQ@mail.gmail.com/T/ But at that time, VM_SHADOW_STACK for riscv meant only VM_WRITE. So I think there was obvious uneasiness with that part. Now we have VM_SHADOW_STACK pretty much same for all arches and only 64bit. I'll try it again as a separate patch. > >-- >Cheers, > >David / dhildenb >