[PATCH 3.16.y-ckt 044/185] powerpc/perf: Fix book3s kernel to userspace backtraces

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Anton Blanchard commit 72e349f1124a114435e599479c9b8d14bfd1ebcd upstream. When we take a PMU exception or a software event we call perf_read_regs(). This overloads regs->result with

[PATCH 3.16.y-ckt 044/185] powerpc/perf: Fix book3s kernel to userspace backtraces

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Anton Blanchard an...@samba.org commit 72e349f1124a114435e599479c9b8d14bfd1ebcd upstream. When we take a PMU exception or a software event we call perf_read_regs(). This overloads