SYS_readv
case SYS_readv:
(code) == SYS_pread64 || (code) == SYS_readv || \
((what == SYS_readv || what == SYS_recvmsg) &&
case SYS_readv:
long nb = (what == SYS_readv)? r0 : 32*1024;
if ((what == SYS_readv && !err &&
praddset(&traceeven, SYS_readv);