Messages in this thread | | | Date | Thu, 1 Nov 2018 21:00:38 +0200 (EET) | From | Jarkko Sakkinen <> | Subject | Re: RFC: userspace exception fixups |
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On Thu, 1 Nov 2018, Florian Weimer wrote: > * Andy Lutomirski: > >> The basic idea would be to allow libc, or maybe even any library, to >> register a handler that gets a chance to act on an exception caused by >> a user instruction before a signal is delivered. As a straw-man >> example for how this could work, there could be a new syscall: >> >> long register_exception_handler(void (*handler)(int, siginfo_t *, void *)); >> >> If a handler is registered, then, if a synchronous exception happens >> (page fault, etc), the kernel would set up an exception frame as usual >> but, rather than checking for signal handlers, it would just call the >> registered handler. That handler is expected to either handle the >> exception entirely on its own or to call one of two new syscalls to >> ask for normal signal delivery or to ask to retry the faulting >> instruction. > > Would the exception handler be a per-thread resource?
For SGX purposes it would *need* to be per-thread resource so that the run-time (not just Intel but any user space support code for SGX) is able to act on thread that caused this exception inside the enclave.
/Jarkko
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