cmd/link,debug/elf: mark Go binaries with no branch target CFI on openbsd
OpenBSD enables Indirect Branch Tracking (IBT) on amd64 and Branch Target
Identification (BTI) on arm64, where hardware permits. Since Go generated
binaries do not currently support IBT or BTI, temporarily mark them with
PT_OPENBSD_NOBTCFI which prevents branch target CFI from being enforced
on execution. This should be removed as soon asn IBT and BTI support are
available.
Fixes #66040
Updates #66054
Change-Id: I91ac05736e6942c54502bef4b8815eb8740d2d5e
Reviewed-on: https://go-review.googlesource.com/c/go/+/568435
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Josh Rickmar <jrick@zettaport.com> Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Joel Sing <joel@sing.id.au> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Than McIntosh <thanm@google.com>