[PATCH 2/2] boot: extlinux: Fix unaligned buffer for reading data from file system

[Nam Cao]

Hi Simon,

On Thu, Nov 07, 2024 at 06:44:30AM -0700, Simon Glass wrote:
> On Wed, 6 Nov 2024 at 09:34, Nam Cao <namcao at linutronix.de> wrote:
> >
> > extlinux_read_bootflow() allocates a buffer to read from file system
> > without any alignment.
> >
> > But for some block devices which transfer data via DMA, ARCH_DMA_MINALIGN
> > alignment is required. For example, due to misaligned buffer, the below
> > boot failure is observed.
> >
> > => boot
> > CACHE: Misaligned operation at range [9efa25f8, 9efa27f8]
> > CACHE: Misaligned operation at range [9efa25f8, 9efa27f8]
> > CACHE: Misaligned operation at range [9efa25f8, 9efa27f8]
> > CACHE: Misaligned operation at range [9efa25f8, 9efa27f8]
> > ** Booting bootflow 'mmc at 2194000.bootdev.part_1' with extlinux
> > Ignoring unknown command: �D���D��
> > Boot failed (err=-14)
> >
> > Change the alignment to default (which is ARCH_DMA_MINALIGN).
> >
> > Fixes: 31aefaf89a5b ("bootstd: Add an implementation of distro boot")
> > Signed-off-by: Nam Cao <namcao at linutronix.de>
> > Tested-by: Javier Fernandez Pastrana <javier.pastrana at linutronix.de>
> > ---
> >  boot/bootmeth_extlinux.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/boot/bootmeth_extlinux.c b/boot/bootmeth_extlinux.c
> > index ae0ad1d53e3..5424d179bf8 100644
> > --- a/boot/bootmeth_extlinux.c
> > +++ b/boot/bootmeth_extlinux.c
> > @@ -127,7 +127,7 @@ static int extlinux_read_bootflow(struct udevice *dev, struct bootflow *bflow)
> >                 return log_msg_ret("try", ret);
> >         size = bflow->size;
> >
> > -       ret = bootmeth_alloc_file(bflow, 0x10000, 1);
> > +       ret = bootmeth_alloc_file(bflow, 0x10000, 0);
> 
> Can you please use ARCH_DMA_MINALIGN here? Either that or update
> bootmeth_script to do the same  as here.

No preference from me. Let's just use ARCH_DMA_MINALIGN here.

Thanks for the comments,
Nam