Messages in this thread | | | From | "H.J. Lu" <> | Date | Fri, 28 Aug 2020 04:37:28 -0700 | Subject | Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack |
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On Thu, Aug 27, 2020 at 11:24 PM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > Can you think of ANY issues of passing more arguments to arch_prctl? > > On x32, the glibc arch_prctl system call wrapper only passes two > arguments to the kernel, and applications have no way of detecting that. > musl only passes two arguments on all architectures. It happens to work > anyway with default compiler flags, but that's an accident.
In the current glibc, there is no arch_prctl wrapper for i386. There are arch_prctl wrappers with 2 arguments for x86-64 and x32. But this isn't an issue for glibc since glibc is both the provider and the user of the new arch_prctl extension. Besides,
long syscall(long number, ...);
is always available.
-- H.J.
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