On Wed, 2022-02-16 at 14:59 +0900, Tomasz Figa wrote: > On Wed, Feb 16, 2022 at 2:55 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > > > > On Thu, 2022-01-27 at 12:08 +0100, AngeloGioacchino Del Regno > > wrote: > > > Il 25/01/22 09:56, Yong Wu ha scritto: > > > > No need zero for the protect buffer that is only accessed by > > > > the > > > > IOMMU HW > > > > translation fault happened. > > > > > > > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > > > > > > I would rather keep this a devm_kzalloc instead... the cost is > > > very > > > minimal and > > > this will be handy when new hardware will be introduced, as it > > > may > > > require a bigger > > > buffer: in that case, "older" platforms will use only part of it > > > and > > > we may get > > > garbage data at the end. > > > > Currently this is to avoid zero 512 bytes for all the platforms. > > > > Sorry, I don't understand why it is unnecessary when the new > > hardware > > requires a bigger buffer. If the buffer becomes bigger, then > > clearing > > it to 0 need more cost. then this patch is more helpful? > > > > The content in this buffer is garbage, we won't care about or > > analyse > > it. > > I think we should zero it for security reasons regardless of any > other > aspects. With this patch it's leaking kernel data to the hardware. > > At the same time, we're talking here about something executed just 1 > time when the driver probes. I don't think the cost would really > matter. OK. I will remove this patch in next version. Thanks. > > Best regards, > Tomasz > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-mediatek
