Mikael Pettersson wrote: > Nathan Lynch writes: > > Some IBM POWER-based platforms have the ability to run in a > > mode which mostly appears to the OS as a different processor from the > > actual hardware. For example, a Power6 system may appear to be a > > Power5+, which makes the AT_PLATFORM value "power5+". > > > > However, some applications (virtual machines, optimized libraries) can > > benefit from knowledge of the underlying CPU model. A new aux vector > > entry, AT_BASE_PLATFORM, will denote the actual hardware. For > > example, on a Power6 system in Power5+ compatibility mode, AT_PLATFORM > > will be "power5+" and AT_BASE_PLATFORM will be "power6". > > Why on earth would you ever want AT_PLATFORM to differ from AT_BASE_PLATFORM? > In cases that matter you admit that AT_BASE_PLATFORM takes precedence, > so why involve a fake lame not-quite-the-platform in the first place? > > Workaround for buggy software?
My apologies, I did not explain the motivation well. The idea is that while AT_PLATFORM indicates the instruction set supported, AT_BASE_PLATFORM indicates the underlying microarchitecture. It's not a matter of buggy software, or of one value taking precedence over the other. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
