[coreboot] [PATCH] Streamline CPU_ADDR_BITS usage

Scott Duplichan scott at notabs.org
Mon Oct 4 02:14:36 CEST 2010

]But note that the current form is also a bit dangerous. It hardcodes 40bits
]for K8 and 48bits for Fam10h here unconditionally. I don't know if this
]assumption is always correct for all CPUs. Using the correct per-CPU
]CONFIG_CPU_ADDR_BITS_MASK would definately be safer (if this mechanism
]can work here at all). Are we sure there are no K8 systems that support
]CPUs with bits != 40? Are we sure there are no Fam10h CPUs with
]bits != 48 (and that there never will be in the future)?

Getting this info from cpuid is the way to go (It is reliable on AMD
systems). Hard-coding is next best. It is fixed per family:

0Fh 40
10h 48
11h 40
12h 40
13h (no product)
14h 36
15h 48

Hopefully AMD will start supplying coreboot-ready support code, which
will allow coreboot to run exactly the same reference code as every
other AMD BIOS.


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