perf/x86_64: Improve user regs sampling

Perf reports user regs for kernel-mode samples so that samples can
be backtraced through user code.  The old code was very broken in
syscall context, resulting in useless backtraces.

The new code, in contrast, is still dangerously racy, but it should
at least work most of the time.

Tested-by: Jiri Olsa <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: Wu Fengguang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/243560c26ff0f739978e2459e203f6515367634d.1420396372.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions