Re: [PATCH 0/3] powerpc: Emulation support for load/store instructions on LE

On 2016/11/02 02:23PM, Ravi Bangoria wrote:

emulate_step is the basic infrastructure which is used by number of other
kernel infrastructures like kprobe, hw-breakpoint(data breakpoint) etc.
In case of kprobe, enabling emulation of load/store instructions will
speedup the execution of probed instruction. In case of kernel-space
breakpoint, causative instruction is first get emulated before executing
user registered handler. If emulation fails, hw-breakpoint is disabled
with error. As emulate_step does not support load/store instructions on
LE, kernel-space hw-breakpoint infrastructure is broken on LE.

emulate_step() uses a number of underlying kernel functions that were
initially not enabled for LE. This has been rectified since. So, fix
emulate_step() for LE for the corresponding instructions.

Also add selftest which will run at boot if CONFIG_KPROBES_SANITY_TEST
and CONFIG_PPC64 is set.

Changes w.r.t. RFC:
  - Enable emulation support for all types of (Normal, Floating Point,
    Vector and Vector Scalar) load/store instructions.
  - Introduce selftest to test emulate_step for load/store instructions.

Ravi Bangoria (3):
  powerpc: Emulation support for load/store instructions on LE
  powerpc: Add encoding for couple of load/store instructions
  powerpc: emulate_step test for load/store instructions

 arch/powerpc/include/asm/ppc-opcode.h |   7 +
 arch/powerpc/include/asm/sstep.h      |   8 +
 arch/powerpc/kernel/kprobes.c         |   2 +
 arch/powerpc/lib/Makefile             |   4 +
 arch/powerpc/lib/sstep.c              |  20 --
 arch/powerpc/lib/test_emulate_step.c  | 439 ++++++++++++++++++++++++++++++++++
 6 files changed, 460 insertions(+), 20 deletions(-)
 create mode 100644 arch/powerpc/lib/test_emulate_step.c

Patch 2 can be folded into the third patch. Apart from that, and the 
minor nit with patch 3, for this series:
Reviewed-by: Naveen N. Rao <redacted>

Thanks,
Naveen