>>>>> Benjamin Herrenschmidt writes:
Ben> There seem to be a problem with gcc 4.0 and implicit generation of
Ben> altivec instructions when -mcpu=970.
Ben> The problem is that the kernel cannot afford to use altivec instructions
Ben> (nor FPU) except in controlled environment. Specifically, things like
Ben> the RAID6 code has altivec (and SSE/2, which I think has a similar
Ben> problem) implementation which runs in the proper environment.
Ben> In order to build that, we have -mcpu=970. Unfortunately, with 4.0, that
Ben> causes gcc to implicitely generate altivec code, which breaks it all.
Geoff made the decision to enable Altivec implicitly for
processors that support it and to use Altivec for block moves. We need to
find out what he had in mind for situations like this.
One work around is to use -mcpu=power4 instead of -mcpu=970, to
avoid enabling Altivec when compiling kernel code.
David
