> > > I would say, problem is because omap3-n900 binary DT is too large
>
> I agree.
>
> > OK if that's the case, then your patch makes sense to me. It also
> > seems we can have the temporary stack be larger than the initial
> > stack just for atags_to_fdt.
>
> The stack size isn't the issue, but rather its location. We need to
> position it away from the DT data. The DT size is known and we could
> use that, plus some room for the insertion of new data coming from the
> ATAG conversion.
>
> Something like the following would be a more robust solution:
Tested-by: Pavel Machek <pavel@xxxxxx>
(Note, that in 3.19 dts for n900 got too big, so we are actually
triggering old bugs. That means that this is a regression fix, and
should go in ASAP).
>
> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> index 68be901759..89718de9dd 100644
> --- a/arch/arm/boot/compressed/head.S
> +++ b/arch/arm/boot/compressed/head.S
> @@ -263,16 +263,37 @@ restart: adr r0, LC0
> * OK... Let's do some funky business here.
> * If we do have a DTB appended to zImage, and we do have
> * an ATAG list around, we want the later to be translated
> - * and folded into the former here. To be on the safe side,
> - * let's temporarily move the stack away into the malloc
> - * area. No GOT fixup has occurred yet, but none of the
> - * code we're about to call uses any global variable.
> + * and folded into the former here. No GOT fixup has occurred
> + * yet, but none of the code we're about to call uses any
> + * global variable.
> */
> - add sp, sp, #0x10000
> +
> + /* Get the initial DTB size */
> + ldr r5, [r6, #4]
> +#ifndef __ARMEB__
> + /* convert to little endian */
> + eor r1, r5, r5, ror #16
> + bic r1, r1, #0x00ff0000
> + mov r5, r5, ror #8
> + eor r5, r5, r1, lsr #8
> +#endif
> + /* 50% DTB growth should be good enough */
> + add r5, r5, r5, lsr #1
> + /* preserve 64-bit alignment */
> + add r5, r5, #7
> + bic r5, r5, #7
> + /* clamp to 32KB min and 1MB max */
> + movs r1, r5, lsr #15
> + moveq r5, #(1 << 15)
> + movs r1, r5, lsr #20
> + movne r5, #(1 << 20)
> +
> + /* Temporarily relocate the stack past the DTB work space */
> + add sp, sp, r5
> stmfd sp!, {r0-r3, ip, lr}
> mov r0, r8
> mov r1, r6
> - sub r2, sp, r6
> + mov r2, r5
> bl atags_to_fdt
>
> /*
> @@ -285,11 +306,11 @@ restart: adr r0, LC0
> bic r0, r0, #1
> add r0, r0, #0x100
> mov r1, r6
> - sub r2, sp, r6
> + mov r2, r5
> bleq atags_to_fdt
>
> ldmfd sp!, {r0-r3, ip, lr}
> - sub sp, sp, #0x10000
> + sub sp, sp, r5
> #endif
>
> mov r8, r6 @ use the appended device tree
> @@ -306,7 +327,7 @@ restart: adr r0, LC0
> subs r1, r5, r1
> addhi r9, r9, r1
>
> - /* Get the dtb's size */
> + /* Get the current DTB size */
> ldr r5, [r6, #4]
> #ifndef __ARMEB__
> /* convert r5 (dtb size) to little endian */
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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