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From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Tue, 23 Feb 2021 08:49:17 -0800
Message-ID: <CABCJKuemAmeaSshvb=B6D1kBt-n_unEx11rwzOZmDxAd+EQ31g@mail.gmail.com>
Subject: Re: [PATCH] remoteproc: core: Remove casting to rproc_handle_resource_t
To:     Mathieu Poirier <mathieu.poirier@linaro.org>
Cc:     Jindong Yue <jindong.yue@nxp.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-remoteproc <linux-remoteproc@vger.kernel.org>,
        Peng Fan <peng.fan@nxp.com>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Feb 23, 2021 at 8:41 AM Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> On Mon, 22 Feb 2021 at 15:48, Sami Tolvanen <samitolvanen@google.com> wrote:
> >
> > Hi,
> >
> > On Sun, Feb 21, 2021 at 11:18 PM Jindong Yue <jindong.yue@nxp.com> wrote:
> > >
> > > There are four different callback functions that are used for the
> > > rproc_handle_resource_t callback that all have different second
> > > parameter types.
> > >
> > > rproc_handle_vdev -> struct fw_rsc_vdev
> > > rproc_handle_trace -> struct fw_rsc_trace
> > > rproc_handle_devmem -> struct fw_rsc_devmem
> > > rproc_handle_carveout -> struct fw_rsc_carveout
> > >
> > > These callbacks are cast to rproc_handle_resource_t so that there is no
> > > error about incompatible pointer types. Unfortunately, this is a control
> > > flow integrity violation, which verifies that the callback function's
> > > types match the prototypes exactly before jumping.
> >
> > Thank you for sending the patch! It might be worth noting that Clang's
> > Control-Flow Integrity checking is currently used only in Android
> > kernels, so while the type mismatches are real and should be fixed,
> > they don't result in runtime errors without this feature.
> >
> > > To fix this, change the second parameter of all functions to void * and
> > > use a local variable with the correct type so that everything works
> > > properly. With this, we can remove casting to rproc_handle_resource_t
> > > for these functions.
> > >
> > > Signed-off-by: Jindong Yue <jindong.yue@nxp.com>
> > > Reviewed-by: Peng Fan <peng.fan@nxp.com>
> >
> > This looks correct to me. Please feel free to add:
> >
> > Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
>
> Where is the original patch?  I can't find it on the linux-remoteproc
> and linux-kernel mailing lists.

Looks like it was sent to linux-remoteproc, but I also don't see it in
lore.kernel.org. Not sure what happened there. Jindong, perhaps it's
worth resending and including linux-kernel too?

Sami