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Tue, 02 Jun 2020 23:29:00 -0800 Received: from MTKMBS02N1.mediatek.inc (172.21.101.77) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 3 Jun 2020 00:29:08 -0700 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs02n1.mediatek.inc (172.21.101.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 3 Jun 2020 15:29:02 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 3 Jun 2020 15:29:01 +0800 Message-ID: <1591169342.4878.9.camel@mtkswgap22> Subject: Re: Security Random Number Generator support From: Neal Liu To: Marc Zyngier , Julius Werner , Ard Biesheuvel Date: Wed, 3 Jun 2020 15:29:02 +0800 In-Reply-To: <85dfc0142d3879d50c0ba18bcc71e199@misterjones.org> References: <1591085678-22764-1-git-send-email-neal.liu@mediatek.com> <85dfc0142d3879d50c0ba18bcc71e199@misterjones.org> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200603_002915_254003_A5C3EB4E X-CRM114-Status: GOOD ( 16.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Herbert Xu , Arnd Bergmann , Greg Kroah-Hartman , Sean Wang , "linux-mediatek@lists.infradead.org" , lkml , wsd_upstream , Rob Herring , Neal Liu , Linux Crypto Mailing List , Matt Mackall , Matthias Brugger , Crystal Guo =?UTF-8?Q?=28=E9=83=AD=E6=99=B6=29?= , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 2020-06-02 at 21:02 +0800, Marc Zyngier wrote: > On 2020-06-02 13:14, Ard Biesheuvel wrote: > > On Tue, 2 Jun 2020 at 10:15, Neal Liu wrote: > >> > >> These patch series introduce a security random number generator > >> which provides a generic interface to get hardware rnd from Secure > >> state. The Secure state can be Arm Trusted Firmware(ATF), Trusted > >> Execution Environment(TEE), or even EL2 hypervisor. > >> > >> Patch #1..2 adds sec-rng kernel driver for Trustzone based SoCs. > >> For security awareness SoCs on ARMv8 with TrustZone enabled, > >> peripherals like entropy sources is not accessible from normal world > >> (linux) and rather accessible from secure world (HYP/ATF/TEE) only. > >> This driver aims to provide a generic interface to Arm Trusted > >> Firmware or Hypervisor rng service. > >> > >> > >> changes since v1: > >> - rename mt67xx-rng to mtk-sec-rng since all MediaTek ARMv8 SoCs can > >> reuse > >> this driver. > >> - refine coding style and unnecessary check. > >> > >> changes since v2: > >> - remove unused comments. > >> - remove redundant variable. > >> > >> changes since v3: > >> - add dt-bindings for MediaTek rng with TrustZone enabled. > >> - revise HWRNG SMC call fid. > >> > >> changes since v4: > >> - move bindings to the arm/firmware directory. > >> - revise driver init flow to check more property. > >> > >> changes since v5: > >> - refactor to more generic security rng driver which > >> is not platform specific. > >> > >> *** BLURB HERE *** > >> > >> Neal Liu (2): > >> dt-bindings: rng: add bindings for sec-rng > >> hwrng: add sec-rng driver > >> > > > > There is no reason to model a SMC call as a driver, and represent it > > via a DT node like this. > > +1. > > > It would be much better if this SMC interface is made truly generic, > > and wired into the arch_get_random() interface, which can be used much > > earlier. > > Wasn't there a plan to standardize a SMC call to rule them all? > > M. Could you give us a hint how to make this SMC interface more generic in addition to my approach? There is no (easy) way to get platform-independent SMC function ID, which is why we encode it into device tree, and provide a generic driver. In this way, different devices can be mapped and then get different function ID internally. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel