[U-Boot] [PATCH] arm: socfpga: provide default SPL_SIZE_LIMIT for gen5

[Simon Goldschmidt]

Marek Vasut <marex at denx.de> schrieb am Do., 13. Juni 2019, 23:08:

> On 6/13/19 11:00 PM, Simon Goldschmidt wrote:
> >
> >
> > Marek Vasut <marex at denx.de <mailto:marex at denx.de>> schrieb am Do., 13.
> > Juni 2019, 22:56:
> >
> >     On 6/13/19 10:55 PM, Simon Goldschmidt wrote:
> >     >
> >     >
> >     > Marek Vasut <marex at denx.de <mailto:marex at denx.de>
> >     <mailto:marex at denx.de <mailto:marex at denx.de>>> schrieb am Do., 13.
> >     > Juni 2019, 22:40:
> >     >
> >     >     On 6/13/19 10:26 PM, Simon Goldschmidt wrote:
> >     >     >
> >     >     >
> >     >     > On 13.06.19 22:14, Marek Vasut wrote:
> >     >     >> On 6/13/19 9:50 PM, Simon Goldschmidt wrote:
> >     >     >>> This provides an SPL_SIZE_LIMIT that makes the build check
> >     that
> >     >     the SPL
> >     >     >>> binary loaded from flash fits into the SRAM (64 KiB) and
> >     leaves
> >     >     enough
> >     >     >>> room for global data, heap  and stack (512 bytes assumed
> stack
> >     >     usage).
> >     >     >>>
> >     >     >>> Signed-off-by: Simon Goldschmidt
> >     >     <simon.k.r.goldschmidt at gmail.com
> >     <mailto:simon.k.r.goldschmidt at gmail.com>
> >     >     <mailto:simon.k.r.goldschmidt at gmail.com
> >     <mailto:simon.k.r.goldschmidt at gmail.com>>>
> >     >     >>> ---
> >     >     >>>
> >     >     >>>   arch/arm/mach-socfpga/Kconfig | 8 ++++++++
> >     >     >>>   1 file changed, 8 insertions(+)
> >     >     >>>
> >     >     >>> diff --git a/arch/arm/mach-socfpga/Kconfig
> >     >     >>> b/arch/arm/mach-socfpga/Kconfig
> >     >     >>> index 48f02f08d4..1d914648e3 100644
> >     >     >>> --- a/arch/arm/mach-socfpga/Kconfig
> >     >     >>> +++ b/arch/arm/mach-socfpga/Kconfig
> >     >     >>> @@ -3,6 +3,12 @@ if ARCH_SOCFPGA
> >     >     >>>   config NR_DRAM_BANKS
> >     >     >>>       default 1
> >     >     >>>   +config SPL_SIZE_LIMIT
> >     >     >>> +    default 65536 if TARGET_SOCFPGA_GEN5
> >     >     >>> +
> >     >     >>> +config SPL_SIZE_LIMIT_PROVIDE_STACK
> >     >     >>> +    default 0x200 if TARGET_SOCFPGA_GEN5
> >     >     >>> +
> >     >     >>>   config SPL_STACK_R_ADDR
> >     >     >>>       default 0x00800000 if TARGET_SOCFPGA_GEN5
> >     >     >>>   @@ -49,6 +55,8 @@ config TARGET_SOCFPGA_GEN5
> >     >     >>>       bool
> >     >     >>>       select SPL_ALTERA_SDRAM
> >     >     >>>       imply FPGA_SOCFPGA
> >     >     >>> +    imply SPL_SIZE_LIMIT_SUBTRACT_GD
> >     >     >>> +    imply SPL_SIZE_LIMIT_SUBTRACT_MALLOC
> >     >     >>>       imply SPL_STACK_R
> >     >     >>>       imply SPL_SYS_MALLOC_SIMPLE
> >     >     >>>       imply USE_TINY_PRINTF
> >     >     >>>
> >     >     >> 512 bytes for stack looks like it's too little. I think the
> SPL
> >     >     started
> >     >     >> misbehaving when it overgrew 50 kiB, no ?
> >     >     >
> >     >     > To 1: Well, I tested the stack usage once, booting from
> >     eMMC, and was
> >     >     > somewhere below that range. But yes, it's a problem for the
> >     >     future: once
> >     >     > we get a more stack-consuming function, we might be lost.
> >     Which size
> >     >     > would you suggest?
> >     >
> >     >     Hmmm, now that I think about it, the stack gets relocated to
> >     DRAM quite
> >     >     early too, right ? So maybe we really don't need that much
> >     space for
> >     >     stack.
> >     >
> >     >
> >     > Exactly. The only stack-consuming things before relocation are dts
> >     > parsing and maybe the ddr driver. I implemented a stack usage
> check by
> >     > filling the memory with 0xaa and checking it afterwards and if I
> >     > remember correctly it resulted in about 400 bytes. It's even more
> or
> >     > less independent of the boot type since the ski/mmc drivers are
> probed
> >     > only after DDR is up. Same goes for file systems.
> >     >
> >     > Nevertheless, stack usage can increase in the future. That's why
> >     I'm not
> >     > too happy about this constant. Otoh, DM_CLK makes me need every
> >     byte and
> >     > right now I don't see how I can enable secure boot (fit signature
> >     check)
> >     > due to this size limit...
> >
> >     Maybe before we add more bloat, we should consider how to trim the
> bloat
> >     down first ?
> >
> >
> > One of the reasons why I haven't sent the clk driver patches yet.
> >
> > Anyway, I'll be off for at least a week now, I just wanted to get this
> > one in before the release.
>
> So is 0x200 bytes for stack before SPL relocs the stack enough ?
>

For now it's enough, yes.

Regards,
Simon


> > I hope I'll be working on SPL size after that... 64 KiB not being enough
> > is just ridicculous...
>
> Agreed
>
> --
> Best regards,
> Marek Vasut
>