[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] caml-stubdom: fix "red zone" bug
At 17:16 +0100 on 27 Oct (1288199782), Ian Jackson wrote: > Patrick Colp writes ("[Xen-devel] [PATCH] caml-stubdom: fix "red zone" bug"): > > According to the AMD64 ABI, the 128-byte area below %rsp is reserved > > for scratch space and should not be used by signal, interrupt, or > > exception handlers. However, Mini-OS does not adhere to this > > interface. > > How unpleasant. > > > This patch fixes this issue by passing the -mno-red-zone flag to the > > ocaml configure script in the stubdom Makefile. > > Perhaps it would be better to make Mini-OS adhere to the specified > interface? Hmm. We would need to have more heavyweight kernel/user separation to make sure that interrupt delivery &c always happens on safe stacks. At the moment, all of Mini-OS runs in kernel mode, on one stack. It might be possible to use a different stack change for interrupts and exceptions only without having a full user/kernel split though, as long as all the interrupt handlers are compiled with -mno-red-zone... It's really just part of the confusion of running "application" code in what's realy a kernel. The Linux kernel and Xen are both compiled with -mno-red-zone, to avoid this kind of issue. Cheers, Tim. -- Tim Deegan <Tim.Deegan@xxxxxxxxxx> Principal Software Engineer, XenServer Engineering Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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