On Saturday 24 January 2015 00:48:55 Pavel Machek wrote:
> On Fri 2015-01-23 23:36:36, Pali Rohár wrote:
> > On Friday 23 January 2015 22:39:55 Pali Rohár wrote:
> > > Hello,
> > >
> > > when I boot zImage with appended DT n900 in qemu
> > > fdt_open_into() function called from file
> > > arch/arm/boot/compressed/atags_to_fdt.c (in function
> > > atags_to_fdt) always returns -FDT_ERR_NOSPACE.
> > >
> > > It means that all ATAGS (including cmdline arguments)
> > > passed by bootloader are ignored.
> > >
> > > On real n900 device I see that booted DT version also
> > > ignore cmdline arguments from bootloader. I cannot debug
> > > decompress code on real device, but I think it is same
> > > problem as in qemu.
> >
> > Looks like this quick patch is fixing above problem:
> So... something overruns stack, and bigger stack fixes it...?
>
> Pavel
>
Yes, it looks like that DTB file for n900 is too big and
atags_to_fdt.c cannot append anything to it (kernel cmdline)...
> > diff --git a/arch/arm/boot/compressed/head.S
> > b/arch/arm/boot/compressed/head.S index 68be901..4a7d75b
> > 100644
> > --- a/arch/arm/boot/compressed/head.S
> > +++ b/arch/arm/boot/compressed/head.S
> > @@ -268,7 +268,7 @@ restart: adr r0, LC0
> >
> > * area. No GOT fixup has occurred yet, but none of
the
> > * code we're about to call uses any global variable.
> >
> > */
> >
> > - add sp, sp, #0x10000
> > + add sp, sp, #0x20000
> >
> > stmfd sp!, {r0-r3, ip, lr}
> > mov r0, r8
> > mov r1, r6
> >
> > @@ -289,7 +289,7 @@ restart: adr r0, LC0
> >
> > bleq atags_to_fdt
> >
> > ldmfd sp!, {r0-r3, ip, lr}
> >
> > - sub sp, sp, #0x10000
> > + sub sp, sp, #0x20000
> >
> > #endif
> >
> > mov r8, r6 @ use the appended device tree
--
Pali Rohár
pali.rohar@xxxxxxxxx
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