-
Philippe Gerum authored
The syscall form used for issuing requests to the companion core is based on ORing __OOB_SYSCALL_BIT to the syscall register for tagging an out-of-band syscall, which is outside of the valid in-band range for syscall numbers. Unfortunately, this method has a major drawback: tools like Valgrind which track system calls issued by applications may choke on out-of-band system calls since these do not belong to the common set it recognizes. Although adding syscall wrappers to Valgrind might be a solution, this would not be the most practical one for dual kernel syscall interfaces. The most practical approach would be to piggyback on an existing system call which Valgrind (and others) already recognizes. For this reason, Dovetail introduced a new syscall form based on the regular prctl(2) syscall. In order to benefit from this feature, EVL syscalls are now folded into a prctl() request, which the core receives. This change introduces ABI #27. Recent revisions of the EVL core support both the former ABI and the new (prctl-based) one indifferently. Signed-off-by: Philippe Gerum <rpm@xenomai.org>
2dcda22d