[OpenWrt-Devel] [PATCH RFT] ramips: mt7621: use lzma-loader for all devices

[mail at adrianschmutzler.de]

Hi,

> -----Original Message-----
> From: Chuanhong Guo [mailto:gch981213 at gmail.com]
> Sent: Dienstag, 14. April 2020 12:20
> To: Adrian Schmutzler <mail at adrianschmutzler.de>
> Cc: OpenWrt Development List <openwrt-devel at lists.openwrt.org>
> Subject: Re: [OpenWrt-Devel] [PATCH RFT] ramips: mt7621: use lzma-loader
> for all devices
> 
> Hi!
> 
> On Tue, Apr 14, 2020 at 5:27 PM <mail at adrianschmutzler.de> wrote:
> > be aware that LZMA_TEXT_START=0x82000000, so this won't work on any
> 32 MB RAM devices if I calculated right.
> 
> Correct. But I assume there won't be enough memory for userspace
> programs if uncompressed kernel reaches 5MB.
> 
> > This of course won't be a problem for mt7621, but if the same strategy is
> applied to other subtargets, LZMA_TEXT_START might be lowered then.
> > So, maybe it would make sense to lower that right away before testing if
> that applies. (One obviously could also have subtarget-dependent values for
> that or just disable all 32 MB devices as well...) On ath79, for example, this
> value was chosen differently to work on 32 MB RAM devices as well.
> 
> lzma-loader can be executed from anywhere in memory. After being
> executed, the first thing it does is copying itself to defined
> LZMA_TEXT_START. We don't really need to test a change of
> LZMA_TEXT_START on every boards as its our own code doing the same
> thing. So I'd like to leave this untouched and change it later if needed.

That's not what I'm aiming at, but in ath79 we had the problem that the uncompressed part became too big and was overwriting the lzma-loader:
https://github.com/openwrt/openwrt/commit/071a6372762d289b2fa5a8d1a138eff944c93c9e

If we move LZMA_TEXT_START closer to the start, that might be an issue in ramips as well (though, only theoretically). That's what I meant with testing.

I didn't want to stop you, though, I just wanted to make you aware of the situation. Most probably it won't matter at the end.

Best

Adrian

> 
> --
> Regards,
> Chuanhong Guo
-------------- next part --------------
A non-text attachment was scrubbed...
Name: openpgp-digital-signature.asc
Type: application/pgp-signature
Size: 834 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/openwrt-devel/attachments/20200414/172f8ac2/attachment.sig>
-------------- next part --------------
_______________________________________________
openwrt-devel mailing list
openwrt-devel at lists.openwrt.org
https://lists.openwrt.org/mailman/listinfo/openwrt-devel