[flashrom] [PATCH] Handle denied access to cbtable gracefuly

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Mon Feb 1 18:04:34 CET 2010

On 01.02.2010 17:12, Stefan Reinauer wrote:
> On 2/1/10 5:41 AM, Carl-Daniel Hailfinger wrote:
>> Stefan: Could you please test this one on Mac OS X? In theory it should
>> even allow us to kill the start=0x400 special case for Mac OS X.
> Sorry I don't have a machine with OSX and coreboot table at my disposal
> right now, but on my macbookpro I get this:
> flashrom v0.9.1-r888
> Mapping low megabyte at 0x00000400, unaligned size 0xffc00.
> Mapping low megabyte, 0xffc00 bytes at unaligned 0x00000400.
> No coreboot table found.
> sh: dmidecode: command not found
> Found chipset "Intel ICH8M", enabling flash write... OK.
> This chipset supports the following protocols: FWH,SPI.
> Calibrating delay loop... OK.
> Found chip "SST SST25VF016B" (2048 KB, SPI) at physical address 0xffe00000.
> ===
> This flash part has status UNTESTED for operations: ERASE
> Please email a report to flashrom at flashrom.org if any of the above
> operations
> work correctly for you with this flash part. Please include the flashrom
> output with the additional -V option for all operations you tested (-V, -rV,
> -wV, -EV), and mention which mainboard or programmer you tested. Thanks
> for your help!
> ===
> No operations were specified.
> However, I'd prefer a 1 line special case over adding 64 lines to the
> normal case for the reason ;-)

Thanks for testing.

The problem was that the mapping failed on some Linux machines because
the kernel detected a mismatch between the PAT/MTRR (cached
write-combining) and the requested mapping type (uncached) for the
coreboot tables. That's why I introduced all the special code (a
one-liner wouldn't have worked). The side effect of being able to use
start=0x0 in the cbtables code under OS X is just a lucky coincidence.

For me, three things are important about this patch:
1. Does it fix the mapping on some Linux kernels/machines?
2. Does it still work on previously working Linux machines?
3. Does it still work on Mac OS X?

So far, at least requirement 2 seems to be fulfilled.


Developer quote of the year:
"We are juggling too many chainsaws and flaming arrows and tigers."

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