Re: [PATCH v9 00/13] firmware: qcom: qseecom: convert to using the TZ allocator

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On Mon, Mar 25, 2024 at 11:04 AM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> SCM calls that take memory buffers as arguments require that they be
> page-aligned, physically continuous and non-cachable. The same
> requirements apply to the buffer used to pass additional arguments to SCM
> calls that take more than 4.
> To that end drivers typically use dma_alloc_coherent() to allocate memory
> of suitable format which is slow and inefficient space-wise.
> SHM Bridge is a safety mechanism that - once enabled - will only allow
> passing buffers to the TrustZone that have been explicitly marked as
> shared. It improves the overall system safety with SCM calls and is
> required by the upcoming scminvoke functionality.
> The end goal of this series is to enable SHM bridge support for those
> architectures that support it but to that end we first need to unify the
> way memory for SCM calls is allocated. This in itself is beneficial as
> the current approach of using dma_alloc_coherent() in most places is quite
> slow.
> First let's add a new TZ Memory allocator that allows users to create
> dynamic memory pools of format suitable for sharing with the TrustZone.
> Make it ready for implementing multiple build-time modes.
> Convert all relevant drivers to using it. Add separate pools for SCM core
> and for qseecom.
> Finally add support for SHM bridge and make it the default mode of
> operation with the generic allocator as fallback for the platforms that
> don't support SHM bridge.
> Tested on db410c, RB5, sm8550-qrd. Previous iteration tested also on
> sa8775p-ride and lenovo X13s (please do retest on those platforms if you
> can).

The Subject should have been "firmware: qcom: implement support for
and enable SHM bridge", sorry for the mixup.


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