[PATCH] cmd: sf: prevent overwriting the reserved memory

[Kummari, Prasad]

Hi Simon,

> -----Original Message-----
> From: Simon Glass <sjg at chromium.org>
> Sent: Wednesday, August 7, 2024 8:06 PM
> To: Kummari, Prasad <Prasad.Kummari at amd.com>
> Cc: u-boot at lists.denx.de; git (AMD-Xilinx) <git at amd.com>; Simek, Michal
> <michal.simek at amd.com>; Abbarapu, Venkatesh
> <venkatesh.abbarapu at amd.com>; git at xilinx.com;
> jagan at amarulasolutions.com; n-francis at ti.com; d-gole at ti.com
> Subject: Re: [PATCH] cmd: sf: prevent overwriting the reserved memory
> 
> Caution: This message originated from an External Source. Use proper
> caution when opening attachments, clicking links, or responding.
> 
> 
> Hi Prasad,
> 
> On Tue, 6 Aug 2024 at 23:05, Kummari, Prasad <Prasad.Kummari at amd.com> wrote:
> >
> > Hi Glass,
> >
> > > -----Original Message-----
> > > From: Simon Glass <sjg at chromium.org>
> > > Sent: Wednesday, August 7, 2024 3:21 AM
> > > To: Kummari, Prasad <Prasad.Kummari at amd.com>
> > > Cc: u-boot at lists.denx.de; git (AMD-Xilinx)
> <git at amd.com>; Simek,
> > > Michal <michal.simek at amd.com>; Abbarapu,
> Venkatesh
> > > <venkatesh.abbarapu at amd.com>; git at xilinx.com;
> > > jagan at amarulasolutions.com; n-francis at ti.com; d-gole at ti.com
> > > Subject: Re: [PATCH] cmd: sf: prevent overwriting the reserved
> > > memory
> > >
> > > Caution: This message originated from an External Source. Use proper
> > > caution when opening attachments, clicking links, or responding.
> > >
> > >
> > > Hi Prasad,
> > >
> > > On Tue, 6 Aug 2024 at 06:08, Prasad Kummari <prasad.kummari at amd.com> wrote:
> > > >
> > > > Added LMB API to prevent SF command from overwriting reserved
> > > > memory areas. The current SPI code does not use LMB APIs for
> > > > loading data into memory addresses. To resolve this, LMB APIs were
> > > > added to check the load address of an SF command and ensure it
> > > > does not overwrite reserved memory addresses. Similar checks are
> > > > used in TFTP, serial load, and boot code to prevent overwriting reserved
> memory.
> > >
> > > The SPI flash may be used to load other things, not just an OS. What
> > > is your use case or problem here?
> >
> > [Prasad]:  We have observed that SF command can overwrite the reserved
> area without throwing any errors or warnings.
> >  This issue was noticed when the TF-A area is reserved in the Device
> > Tree at address 0xf000000. The sf command is  corrupting the reserved
> area,  and U-Boot relocation address too.
> >
> > EX: TF-A reserved at ddr address 0xf000000
> >
> >       Versal NET> sf read 0x0f000000 0x0 0x100     ----> Overwriting reserved
> area.
> >       device 0 offset 0x0, size 0x100
> >       SF: 256 bytes @ 0x0 Read: OK
> >
> >      U-boot relocation address relocaddr   = 0x000000007fec2000
> >
> >       Versal NET> sf write 0x0000000077ec2000 0x0 0x100   --> Overwriting
> reserved area.
> >       device 0 offset 0x0, size 0x100
> >       SF: 256 bytes @ 0x0 Written: OK
> 
> Yes. There are many things which can overwrite memory, e.g. the mw
> command. It is a boot loader so this is normal.
> 
> What image are you loading here?

[Prasad] : We are loading TF-A(bl31.elf) at ddr address 0xf000000.

> 
> Regards,
> Simon