The current system call restart doesn't change the system call number. We just
substract two from the psw address (aka eip) and go back to user space.
> One thing you could do (which is pretty much architecture-independent) is
> to have a "restart" flag in the thread info structure. The system call
> entry code-path already has to check the thread info structure for things
> like the "ptrace" flags, so it shouldn't add much overhead to the system
> call entrypoint.
Hmm, probably the best thing to do. I though about changing the return address
in the last frame of the stack but this is ugly and confuses the code. Another
flag in thread_info (_TIF_RESTART?) doesn't add any instruction on the hot
path in the system call handler and is simple enough to implement.
blue skies,
Martin
Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH
Schönaicherstr. 220, D-71032 Böblingen, Telefon: 49 - (0)7031 - 16-2247
E-Mail: schwidefsky@de.ibm.com
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