From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2223E1109; Sun, 12 May 2024 16:30:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715531430; cv=none; b=OPNHxpt6jy2ZUUTEJ6ucZOwH5QI64ckILXMQ7asSpSiDURQbFaL4+z7TQBL6mEApN+wJInIiqUTZEuq9CPyux2m1v4xplqLqeiF/1H5xhjx/DrXQvOebTQMEXRilG/QKAMP5YvUGSkjxTHb9gbM9N8xsMRqcbv6doBogQtEVyM0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715531430; c=relaxed/simple; bh=0HdeaOF1XK2sxOtEvQ5oWU9I6tjX477QwMYRfdMojhk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JF/yTD7BVyvcHvc34jWTr8SgdLhOyjHh7ZxvZXMpXk+dxoH8AL5gbPI0N1ntstkCTBRvFRTdffNadYPJWCiKPbjd+0TgCExZt6x/t1ErauH5ys00+Ip48ji5rXVlPd7CTV+RsRexMd420czz/Zd6MaZ0O6+lvPSlg+Ejifl+Opc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ghiti.fr; spf=pass smtp.mailfrom=ghiti.fr; arc=none smtp.client-ip=217.70.183.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ghiti.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ghiti.fr Received: by mail.gandi.net (Postfix) with ESMTPSA id B667840006; Sun, 12 May 2024 16:29:03 +0000 (UTC) Message-ID: Date: Sun, 12 May 2024 18:28:59 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 12/29] riscv mmu: teach pte_mkwrite to manufacture shadow stack PTEs Content-Language: en-US To: Deepak Gupta , 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, bjorn@rivosinc.com, alexghiti@rivosinc.com, samuel.holland@sifive.com, conor@kernel.org Cc: 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, david@redhat.com, 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 References: <20240403234054.2020347-1-debug@rivosinc.com> <20240403234054.2020347-13-debug@rivosinc.com> From: Alexandre Ghiti In-Reply-To: <20240403234054.2020347-13-debug@rivosinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-GND-Sasl: alex@ghiti.fr On 04/04/2024 01:35, Deepak Gupta wrote: > pte_mkwrite creates PTEs with WRITE encodings for underlying arch. > Underlying arch can have two types of writeable mappings. One that can be > written using regular store instructions. Another one that can only be > written using specialized store instructions (like shadow stack stores). > pte_mkwrite can select write PTE encoding based on VMA range (i.e. > VM_SHADOW_STACK) > > Signed-off-by: Deepak Gupta > --- > arch/riscv/include/asm/pgtable.h | 7 +++++++ > arch/riscv/mm/pgtable.c | 21 +++++++++++++++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 6362407f1e83..9b837239d3e8 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -403,6 +403,10 @@ static inline pte_t pte_wrprotect(pte_t pte) > > /* static inline pte_t pte_mkread(pte_t pte) */ > > +struct vm_area_struct; > +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma); > +#define pte_mkwrite pte_mkwrite > + > static inline pte_t pte_mkwrite_novma(pte_t pte) > { > return __pte(pte_val(pte) | _PAGE_WRITE); > @@ -694,6 +698,9 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd) > return pte_pmd(pte_mkyoung(pmd_pte(pmd))); > } > > +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); > +#define pmd_mkwrite pmd_mkwrite > + > static inline pmd_t pmd_mkwrite_novma(pmd_t pmd) > { > return pte_pmd(pte_mkwrite_novma(pmd_pte(pmd))); > diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c > index ef887efcb679..c84ae2e0424d 100644 > --- a/arch/riscv/mm/pgtable.c > +++ b/arch/riscv/mm/pgtable.c > @@ -142,3 +142,24 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, > return pmd; > } > #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > + > +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) > +{ > + if (vma_is_shadow_stack(vma->vm_flags)) > + return pte_mkwrite_shstk(pte); > + > + pte = pte_mkwrite_novma(pte); I would directly return pte_mkwrite_novma(pte) instead of assigning pte. > + > + return pte; > +} > + > +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) > +{ > + if (vma_is_shadow_stack(vma->vm_flags)) > + return pmd_mkwrite_shstk(pmd); > + > + pmd = pmd_mkwrite_novma(pmd); Ditto here. > + > + return pmd; > +} > + Otherwise: Reviewed-by: Alexandre Ghiti Thanks, Alex