tree 725a7b6d7c2b67a7b90e2270f04a0303232a9cc3
parent 39a67d49ba353630d144a8eb775500c041c89e7a
author William Cohen <wcohen@redhat.com> 1467995752 -0400
committer Catalin Marinas <catalin.marinas@arm.com> 1468937002 +0100

arm64: Add trampoline code for kretprobes

The trampoline code is used by kretprobes to capture a return from a probed
function.  This is done by saving the registers, calling the handler, and
restoring the registers. The code then returns to the original saved caller
return address. It is necessary to do this directly instead of using a
software breakpoint because the code used in processing that breakpoint
could itself be kprobe'd and cause a problematic reentry into the debug
exception handler.

Signed-off-by: William Cohen <wcohen@redhat.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: removed unnecessary masking of the PSTATE bits]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>