From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel@stlinux.com,
maxime.coquelin@st.com, ohad@wizery.com,
linux-remoteproc@vger.kernel.org
Subject: Re: [PATCH 5/5] remoteproc: core: Clip carveout if it's too big
Date: Tue, 10 May 2016 12:21:29 -0700 [thread overview]
Message-ID: <20160510192129.GL1256@tuxbot> (raw)
In-Reply-To: <1462454983-13168-6-git-send-email-lee.jones@linaro.org>
On Thu 05 May 06:29 PDT 2016, Lee Jones wrote:
> Carveout size is primarily extracted from the firmware binary. However,
> DT can over-ride this by providing a different (smaller) size. We're
> adding protection here to ensure the we only allocate the smaller of the
> two provided sizes in order to decrease the risk of clashes.
>
Is this really the right thing to do?
The firmware is bundled with a resource table stating a certain size of
this the carveout and this would "silently" give it less space. On some
systems an IOMMU will save us (killing the firmware) but on others I
fear the firmware might just access memory outside its expected buffer.
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> drivers/remoteproc/remoteproc_core.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
[..]
> @@ -600,6 +601,14 @@ static int rproc_handle_carveout(struct rproc *rproc,
> return -ENOMEM;
>
> dma_dev = rproc_subdev_lookup(rproc, "carveout");
> + sub = dev_get_drvdata(dma_dev);
> +
> + if (rsc->len > resource_size(sub->res)) {
> + dev_warn(dev, "carveout too big (0x%x): clipping to 0x%x\n",
> + rsc->len, resource_size(sub->res));
> + rsc->len = resource_size(sub->res);
> + }
I would rather expect this to say:
if (resource_size(sub->res) < rsc->len) {
dev_err(dev, "defined carveout to small for firmware\n");
return -EINVAL;
}
Unless we trust the remote firmware to dynamically follow what we put in
the resource table. (And how does it tell us if that limit isn't
enough?)
> +
> va = dma_alloc_coherent(dma_dev, rsc->len, &dma, GFP_KERNEL);
> if (!va) {
> dev_err(dev->parent, "dma_alloc_coherent err: %d\n", rsc->len);
Apart from this concern I'm still need to review the subdev patch; here
related the part that there's only room for one carveout with only one
size.
Regards,
Bjorn
next prev parent reply other threads:[~2016-05-10 19:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 13:29 [PATCH 0/5] remoteproc: A few important improvements Lee Jones
2016-05-05 13:29 ` [PATCH 1/5] remoteproc: core: Task sync during rproc_fw_boot() Lee Jones
2016-05-06 18:44 ` Bjorn Andersson
2016-05-05 13:29 ` [PATCH 2/5] remoteproc: core: Add rproc OF look-up functions Lee Jones
2016-05-06 18:48 ` Bjorn Andersson
2016-05-10 14:16 ` Lee Jones
2016-05-10 18:48 ` Bjorn Andersson
2016-07-13 19:11 ` Bjorn Andersson
2016-07-14 6:53 ` Lee Jones
2016-05-05 13:29 ` [PATCH 3/5] remoteproc: core: Add ability to select a firmware from the client Lee Jones
2016-05-06 18:59 ` Bjorn Andersson
2016-05-10 13:02 ` Lee Jones
2016-05-05 13:29 ` [PATCH 4/5] remoteproc: core: Supply framework to request, declare and fetch shared memory Lee Jones
2016-05-11 22:30 ` Bjorn Andersson
2016-06-15 22:06 ` Bjorn Andersson
2016-06-21 7:33 ` [STLinux Kernel] " loic pallardy
2016-06-22 16:21 ` Bjorn Andersson
2016-05-05 13:29 ` [PATCH 5/5] remoteproc: core: Clip carveout if it's too big Lee Jones
2016-05-10 19:21 ` Bjorn Andersson [this message]
2016-06-17 19:53 ` [STLinux Kernel] " loic pallardy
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