[Qemu-ppc] linux-user: ppc64: AT_HWCAP bits and e5500 (e500mc, too?)

[Michael Walle]

Hi,

ok this was a tough one. Programs which links to ceil() aborts with 
invalid instruction. The instruction was "frip", which isn't supported 
on e5500 or e500mc. Turns out the libc checks the AT_HWCAP field (dunno 
if that has to do with multilib support) and uses the optimized power5 
code if the ARCH_2_06 bit is set. linux-user sets the ARCH_2_06 bit in 
case of a e5500 core, which is wrong IMHO. In fact the linux kernel sets 
this bit only for POWER[789] CPUs.

The line which sets this bit in linux-user is:

#define GET_FEATURE2(flag, feature)                                      
\
    do { if (cpu->env.insns_flags2 & flag) { features |= feature; } } 
while (0)

GET_FEATURE2((PPC2_PERM_ISA206 | PPC2_DIVE_ISA206 | PPC2_ATOMIC_ISA206 |
              PPC2_FP_CVT_ISA206 | PPC2_FP_TST_ISA206),
              QEMU_PPC_FEATURE_ARCH_2_06);

PPC2_PERM_ISA206 is set for the e5500/e500mc core. Is this really 
intended to set the ARCH_2_06 bit if _any_ of the listed bits is set or 
should it set the ARCH_2_06 bit only if _all_ bits are set. Eg.

#define GET_FEATURES(flag, feature)
    do { if (cpu->env.insns_flags2 & flag == flag) { features |= 
feature; } } while (0)

-michael