Messages in this thread | | | Subject | Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack | From | Dave Hansen <> | Date | Tue, 8 Sep 2020 10:57:25 -0700 |
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On 9/8/20 10:50 AM, Yu, Yu-cheng wrote: > What about this: > > - Do not add any new syscall or arch_prctl for creating a new shadow stack. > > - Add a new arch_prctl that can turn an anonymous mapping to a shadow > stack mapping. > > This allows the application to do whatever is necessary. It can even > allow GDB or JIT code to create or fix a call stack.
Fine with me. But, it's going to effectively be
arch_prctl(PR_CONVERT_TO_SHS..., addr, len);
when it could just as easily be:
madvise(addr, len, MADV_SHSTK...);
Or a new syscall. The only question in my mind is whether we want to do something generic that we can use for other similar things in the future, like:
madvise2(addr, len, flags, MADV2_SHSTK...);
I don't really feel strongly about it, though. Could you please share your logic on why you want a prctl() as opposed to a whole new syscall?
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