On Mon, Dec 02, 2019 at 07:11:46PM +0000, Marc Zyngier wrote: > On Mon, 2 Dec 2019 16:12:09 +0000 > Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > > > (adding some more arm64 folks) > > > > On Fri, 29 Nov 2019 at 11:30, Neal Liu <neal.liu@xxxxxxxxxxxx> wrote: > > > > > > On Fri, 2019-11-29 at 18:02 +0800, Lars Persson wrote: > > > > Hi Neal, > > > > > > > > On Wed, Nov 27, 2019 at 3:23 PM Neal Liu <neal.liu@xxxxxxxxxxxx> wrote: > > > > > > > > > > For MediaTek SoCs on ARMv8 with TrustZone enabled, peripherals like > > > > > entropy sources is not accessible from normal world (linux) and > > > > > rather accessible from secure world (ATF/TEE) only. This driver aims > > > > > to provide a generic interface to ATF rng service. > > > > > > > > > > > > > I am working on several SoCs that also will need this kind of driver > > > > to get entropy from Arm trusted firmware. > > > > If you intend to make this a generic interface, please clean up the > > > > references to MediaTek and give it a more generic name. For example > > > > "Arm Trusted Firmware random number driver". > > > > > > > > It will also be helpful if the SMC call number is configurable. > > > > > > > > - Lars > > > > > > Yes, I'm trying to make this to a generic interface. I'll try to make > > > HW/platform related dependency to be configurable and let it more > > > generic. > > > Thanks for your suggestion. > > > > > > > I don't think it makes sense for each arm64 platform to expose an > > entropy source via SMC calls in a slightly different way, and model it > > as a h/w driver. Instead, we should try to standardize this, and > > perhaps expose it via the architectural helpers that already exist > > (get_random_seed_long() and friends), so they get plugged into the > > kernel random pool driver directly. > > Absolutely. I'd love to see a standard, ARM-specified, virtualizable > RNG that is abstracted from the HW. Same here. I hacked up some initial code for doing this with KVM [1], but I'd much rather it was part of a standard service specification so that we could use the same interface for talking to the firmware and the hypervisor. Will [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=kvm/hvc
