Re: Linux Plumbers Conf 2021

Fixing linux-toolchains list address.

On Tue, May 18, 2021 at 07:43:13AM -0500, Josh Poimboeuf wrote:

On Tue, May 18, 2021 at 01:14:48PM +0100, Will Deacon wrote:

quoted

If it's not too late, I'd definitely be interested in a discussion around
objtool support for arm64. Specifically, I would very much like us _not_
to have a hard dependency on objtool and instead treat it as a binary
linter of sorts. However, this likely requires help from the toolchain
where some of the jobs which are performed by objtool on x86 today now
need to be done by the compiler/linker for arm64.

I don't have a good handle on exactly what is needed and whether there's
any appetite from the toolchain developers to implement this, so it would
be very helpful to kick that discussion off.

Objtool stack validation already is pretty much a "binary linter".  If
all the warnings are fixed then we can trust the unwind metadata (e.g.
frame pointers) for reliable unwinding / live patching.

All warnings are expected to be fixed by humans, so objtool doesn't have
to edit the binary (assuming no ORC, which is optional).  Objtool is
only considered a hard dependency for live patching because unfixed
warnings could mean a livepatch fail.

So I wonder what specifically you have in mind?

-- 
Josh

-- 
Josh