On arm64 the eret instruction is used to return from an exception handler.
Some implementations may speculate past this instruction into the next
function. As the user may control many registers in these functions add
a synchronisation barrier sequence after the eret instruction to stop these
CPUs from speculating out of the exception handler.
PR: 242676
Submitted by: Anthony Steinhauser <asteinhauser@google.com> (previous version)
MFC after: 1 week
from the kernel. Make use of this to restrict accessing userspace to just
the functions that explicitly handle crossing the user kernel boundary.
Reported by: kib
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10371
GNU toolchain does not recognize LR as standard register alias,
but clang does. Use of #define will work on both. Place the
definition into central machine/asm.h instead of patching every
affected file, as requested by plaftorm maintainers.
Reviews by: andrew, emaste, imp
Differential Revision: https://reviews.freebsd.org/D10307
the dynamic linker copy them, but not relocate them at the new location.
This allows us to run sqlite3 without it crashing.
Sponsored by: ABT Systems Ltd
