[PATCH v4 0/2] powerpc: Emulation support for load/store instructions on LE

From: Ravi Bangoria
Date: Tue Feb 14 2017 - 09:31:06 EST

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 in v4:
- Used late_initcall() for selftest
- Makefile changes

v3 link: https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1332686.html

Ravi Bangoria (2):
powerpc: Emulation support for load/store instructions on LE
powerpc: emulate_step tests for load/store instructions

arch/powerpc/include/asm/ppc-opcode.h | 7 +
arch/powerpc/lib/Makefile | 2 +
arch/powerpc/lib/sstep.c | 20 --
arch/powerpc/lib/test_emulate_step.c | 443 ++++++++++++++++++++++++++++++++++
4 files changed, 452 insertions(+), 20 deletions(-)
create mode 100644 arch/powerpc/lib/test_emulate_step.c