Re: gptzfsboot problem on HP P410i Smart Array

On Tuesday, March 19, 2013 5:55:45 am Andriy Gapon wrote:
> on 19/03/2013 07:41 Sergey Dyatko said the following:
> > I was faced with same problem on my laptop. Adding printf() into main()
> > before dsk = malloc(sizeof(struct dsk)); fix boot. Yesterday, avg_at_ proposed
> > patch:
> > Index: /usr/src/sys/boot/i386/zfsboot/zfsboot.c
> > ===================================================================
> > --- /usr/src/sys/boot/i386/zfsboot/zfsboot.c    (revision 248421)
> > +++ /usr/src/sys/boot/i386/zfsboot/zfsboot.c    (working copy)
> > _at__at_ -302,6 +302,7 _at__at_
> >       * region in the SMAP, use the last 3MB of 'extended' memory as a
> >       * high heap candidate.
> >       */
> > +       high_heap_size = 0;
> >      if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {
> >         high_heap_size = HEAP_MIN;
> >         high_heap_base = bios_extmem + 0x100000 - HEAP_MIN;
> > 
> > it works for me, without printf() :) Can you test it ?
> 
> A comment about a nature of this patch.
> 
> Based on the previous investigation by Christoph Hoffmann and jhb:
> http://thread.gmane.org/gmane.os.freebsd.current/134199/focus=134309
> I made a guess that either BIOS/firmware provides incorrect memory map or some
> agent in the BIOS/firmware (e.g. SMM handler) or controller firmware writes
> outside of a memory range reserved for it.
> I think that jhb made a similar guess at the time while Christoph conjectured
> that memory corruption was related to CPU caches or some such.
> My conjecture is that it is simply a combination of timing and a particular
> memory range.
> 
> Just in case, here is how the memory map looks on the Sergey's system:
> SMAP type=01 base=0000000000000000 end=000000000009fc00 len=000000000009fc00
> SMAP type=02 base=000000000009fc00 end=00000000000a0000 len=0000000000000400
> SMAP type=02 base=00000000000e0000 end=0000000000100000 len=0000000000020000
> SMAP type=01 base=0000000000100000 end=00000000bc1a1000 len=00000000bc0a1000
> SMAP type=04 base=00000000bc1a1000 end=00000000bc1a4000 len=0000000000003000
> SMAP type=01 base=00000000bc1a4000 end=00000000bdf04000 len=0000000001d60000
> SMAP type=04 base=00000000bdf04000 end=00000000bdf3f000 len=000000000003b000
> SMAP type=01 base=00000000bdf3f000 end=00000000bdf6a000 len=000000000002b000
> SMAP type=02 base=00000000bdf6a000 end=00000000bdfbf000 len=0000000000055000
> SMAP type=01 base=00000000bdfbf000 end=00000000bdfeb000 len=000000000002c000
> SMAP type=03 base=00000000bdfeb000 end=00000000bdfff000 len=0000000000014000
> SMAP type=01 base=00000000bdfff000 end=00000000be000000 len=0000000000001000
> SMAP type=02 base=00000000be000000 end=00000000c0000000 len=0000000002000000
> SMAP type=02 base=00000000f8000000 end=00000000fc000000 len=0000000004000000
> SMAP type=02 base=00000000fec00000 end=00000000fec01000 len=0000000000001000
> SMAP type=02 base=00000000fed10000 end=00000000fed14000 len=0000000000004000
> SMAP type=02 base=00000000fed18000 end=00000000fed1a000 len=0000000000002000
> SMAP type=02 base=00000000fed1c000 end=00000000fed20000 len=0000000000004000
> SMAP type=02 base=00000000fee00000 end=00000000fee01000 len=0000000000001000
> SMAP type=02 base=00000000ffe00000 end=0000000100000000 len=0000000000200000
> SMAP type=01 base=0000000100000000 end=0000000140000000 len=0000000040000000
> 
> The algorithm for placing the heap picks up a range at bc1a4000, which is
> between two ranges of type '4' (ACPI NVS memory).
> So my idea was just to try a different memory range. Seems that it worked.
> 
> P.S. I am not sure why our algorithm for selecting heap location is what it is.
> On all systems that I have I see that the "bios_extmem" range (the one starting
> at 0x100000) is usually the largest one and has more than enough space for both
> the heap and other things that are placed there.

Yes, we likely could start using that, we would just need to ensure it has some
sort of minimum size.  However, maybe it would always have that minimum size as you
are only going to have additional ranges if you have more than 4GB of RAM anyway.
I think though that there were some odd BIOSes that would place a hole at 15-16MB,
and for those the memory region at 1MB is too small.  A minimum size of 16MB might
handle that case correctly while using the first extended region in the common
case.

> Additionally, in the case of zfsboot I think that we do not use memory above 1MB
> for anything else besides the heap.

You load either /boot/zfsloader or the kernel there.

-- 
John Baldwin