[PATCH v5 00/17] objtool: vmlinux.o and noinstr validation

[Peter Zijlstra]

As should be familiar by now; these patches implement the noinstr
(no-instrument) validation in objtool as requested by Thomas, to ensure
critical code (entry for now, idle later) run no unexpected code.

Functions are marked with: noinstr, which implies notrace, noinline and sticks
things in the .noinstr.text section. Such functions can then use instr_begin()
and instr_end() to allow calls to code outside of this section in sanctioned
areas.

On the way of getting there, it also fixes the x86/ftrace trampiline ORC
unwind.