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 94F50C001B0 for ; Thu, 10 Aug 2023 17:21:04 +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-Transfer-Encoding:Content-Type: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=k6EhTMDmgUZOPDFldPnhMAMsgk+Eg2IFxCy1+PQdOWQ=; b=wLbFGcPJfQDQWa 2GCE5pZi8K71NKkyUaZfw8U5g8D8sZ+ERZT4gpQL03GERC4u0vh+zC0Lrh5+yoiGXW9d7OCi1aoAa NRr2VGViG+jKZMT/EPNADT5M60S9dxjMS5oHt2bj97vi1K76Oxce8LjTaZ4Iqj5geXAr/+Ey+5GbU xtp71UUj77twuZPdRYFKOsnBLWVCFG5C4G5aoMGpIFgPNaGJ9jDPwf2v0AegqyYLj6WTdwSZgpLie 1WXd1l4QAz+9NyDF+Kwj6JpBSrPSGJjbrgEX7Pa0IhhZKbaK8QA3AeVhZ3Dl31v7GKWQO0qPESSaf i2u8zJ68Dr7DxbCZ+AJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qU9Kv-008HUR-0D; Thu, 10 Aug 2023 17:20:37 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qU9Ks-008HTk-1G; Thu, 10 Aug 2023 17:20:35 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8BAE960C4E; Thu, 10 Aug 2023 17:20:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45F14C433C8; Thu, 10 Aug 2023 17:20:28 +0000 (UTC) Date: Thu, 10 Aug 2023 18:20:25 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v4 11/36] arm64/mm: Map pages for guarded control stack Message-ID: References: <20230807-arm64-gcs-v4-0-68cfa37f9069@kernel.org> <20230807-arm64-gcs-v4-11-68cfa37f9069@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230807-arm64-gcs-v4-11-68cfa37f9069@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230810_102034_492342_A58123A3 X-CRM114-Status: GOOD ( 19.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Aug 07, 2023 at 11:00:16PM +0100, Mark Brown wrote: > diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c > index 8f5b7ce857ed..8f40198cd44e 100644 > --- a/arch/arm64/mm/mmap.c > +++ b/arch/arm64/mm/mmap.c > @@ -79,8 +79,18 @@ arch_initcall(adjust_protection_map); > > pgprot_t vm_get_page_prot(unsigned long vm_flags) > { > - pteval_t prot = pgprot_val(protection_map[vm_flags & > + pteval_t prot; > + > + /* If this is a GCS then only interpret VM_WRITE. */ > + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { > + if (vm_flags & VM_WRITE) > + prot = _PAGE_GCS; > + else > + prot = _PAGE_GCS_RO; > + } else { > + prot = pgprot_val(protection_map[vm_flags & > (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); > + } > > if (vm_flags & VM_ARM64_BTI) > prot |= PTE_GP; Some combinations here don't make sense like GCS + exec or BTI. I think the code above (correctly) ignores exec but it still sets PTE_GP if BTI (the architecture may allow this but you can't execute from the GCS page anyway). I haven't checked the x86 patches to see when VM_SHADOW_STACK is set but if there's no additional check at a higher level, we should add something to arch_validate_flags(), assuming it's called on those paths. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel