Re: [GNU-linux-libre] linux ppc micropatch.c: why keep it?

[Jeff Moe]

On 8/22/21 3:27 AM, Alexandre Oliva wrote:
> When I got involved with Linux-libre back in 2008, a file named
> micropatch.c already existed in the Linux source tree, in
> arch/powerpc/sysdev/micropatch.c.  It's now in
> arch/powerpc/platforms/8xx/micropatch.c.
>
> The initial version, added back in 2007, had two sets of binary
> "patches".  Comments stated:
>
>    /* Microcode patches for the CPM as supplied by Motorola.
>
> (CPM stands Communication Processor Module)
>
> Despite the appearance that these "patches" could be code rather than
> configuration data, gNewSense (and then BLAG) appear to have decided
> that it could be left in, for reasons unknown to me.  I assumed there
> were good reasons for that, even though I didn't know them, so the
> binary "patches" have remained in Linux-libre releases since then.
>
> For most of the time, they've remained unchanged, except for
> reformatting of the arrays containing them.  Back in Jun 14, 2019, a new
> set of binary "patches" were added.  It was quite similar in appearance
> and spirit, so I also retained it, assuming the same reasons applied.
> Part of the commit message that introduced the new bits states:
>
>      This microcode is provided by Freescale/NXP in Engineering Bulletin
>      EB662 ("MPC8xx I2C/SPI and SMC Relocation Microcode Packages")
>      dated 2006. The binary code is public. The source is not available.
>
> Recently, someone asked in the GNU Linux-libre discussion list why we
> didn't remove these bits.  I don't know the answer.  I wish I did.  I
> find myself wondering whether it should really have been left alone.
>
> Does anyone have any insights to share as to why this might have been
> left in?  Absent more information, if I were to come across it today,
> I'd most certainly have removed it from Linux-libre, so I'm leaning
> towards doing so in the git history rewrite project I've been slowly
> working on.
>
> thanks in advance for any information you may provide,

Hi Alexandre, it looks like you BCC'd me to a list post.

There's a few incorrect assumptions above. I'll just state what I know. 
Here is the original Linux Libre announcement:

https://lists.autistici.org/message/20080221.002845.467ba592.en.html

It does not mention the CPM code. Doing some quick searches for that 
micropatch code and "Linux Libre" the only reference to it that I found 
was your apparent whitelisting of it and the present discussion. I don't 
see anywhere where BLAG/Linux Libre "appear to have decided
that it could be left in". I think the safer assumption is that it was 
missed if it was there at all. That said, that was forever ago and I 
don't really see why it would matter. If it is non-free, yank it, who 
cares what I thought a decade+ ago about it or not? :)

-Jeff