perf auxtrace arm: Support compat_auxtrace_mmap__{read_head|write_tail}

When the tool runs with compat mode on Arm platform, the kernel is in
64-bit mode and user space is in 32-bit mode; the user space can use
instructions "ldrd" and "strd" for 64-bit value atomicity.

This patch adds compat_auxtrace_mmap__{read_head|write_tail} for arm
building, it uses "ldrd" and "strd" instructions to ensure accessing
atomicity for aux head and tail.  The file arch/arm/util/auxtrace.c is
built for arm and arm64 building, these two functions are not needed for
arm64, so check the compiler macro "__arm__" to only include them for
arm building.

Signed-off-by: Leo Yan <[email protected]>
Reviewed-by: James Clark <[email protected]>
Tested-by: James Clark <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Russell King (oracle)" <[email protected]>
Cc: Suzuki Poulouse <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions