Messages in this thread | | | Subject | Re: [RFC PATCH 00/17] objtool: add base support for arm64 | From | "Madhavan T. Venkataraman" <> | Date | Fri, 22 Jan 2021 15:15:12 -0600 |
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On 1/22/21 11:43 AM, Mark Brown wrote: > On Thu, Jan 21, 2021 at 12:54:52PM -0600, Josh Poimboeuf wrote: > >> 2) The shadow stack idea sounds promising -- how hard would it be to >> make a prototype reliable unwinder? > > In theory it doesn't look too hard and I can't see a particular reason > not to try doing this - there's going to be edge cases but hopefully for > reliable stack trace they're all in areas where we would be happy to > just decide the stack isn't reliable anyway, things like nesting which > allocates separate shadow stacks for each nested level for example. > I'll take a look. >
I am a new comer to this discussion and I am learning. Just have some questions. Pardon me if they are obvious or if they have already been asked and answered.
Doesn't Clang already have support for a shadow stack implementation for ARM64? We could take a look at how Clang does it.
Will there not be a significant performance hit? May be, some of it can be mitigated by using a parallel shadow stack rather than a compact one.
Are there any longjmp style situations in the kernel where the stack is unwound by several frames? In these cases, the shadow stack must be unwound accordingly.
Madhavan
> > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
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