Re: 4.0.0-rc4: panic in free_block

[David Miller <davem@davemloft.net>]

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sun, 22 Mar 2015 12:47:08 -0700

> Which was why I was asking how sure you are that memcpy *always*
> copies from low to high.

Yeah I'm pretty sure.

> I don't even know which version of memcpy ends up being used on M7.
> Some of them do things like use VIS. I can follow some regular sparc
> asm, there's no way I'm even *looking* at that. Is it really ok to use
> VIS registers in random contexts?

Yes, using VIS how we do is alright, and in fact I did an audit of
this about 1 year ago.  This is another one of those "if this is
wrong, so much stuff would break"

The only thing funny some of these routines do is fetch 2 64-byte
blocks of data ahead in the inner loops, but that should be fine
right?

On the M7 we'll use the Niagara-4 memcpy.

Hmmm... I'll run this silly sparc kernel memmove through the glibc
testsuite and see if it barfs.

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