commit 3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b
author Max Filippov <jcmvbkbc@gmail.com> Mon Apr 08 01:29:19 2013 +0400
committer Chris Zankel <chris@zankel.net> Thu May 09 01:07:10 2013 -0700
tree 10159f1a9c02b862957d7d196cb1da6bb762ad39
parent 3e4196a5cc9cff50900f3dc8acc3d41e5963fd50

xtensa: provide custom CALLER_ADDR* implementations

Definition of CALLER_ADDR* through __builtin_return_address makes
compiler insert calls to __xtensa_libgcc_window_spill, which in turn
makes fast_syscall_spill_registers syscall that clobbers registers when
called from the kernel mode, leading to invalid opcode exceptions on
return to userspace.

Provide definition for CALLER_ADDR0 as MAKE_PC_FROM_RA(a0, a1) and in
case CONFIG_FRAME_POINTER is enabled extract CALLER_ADDR{1-3} from
stack.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>