[PATCH v2 0/2] powerpc: Emulation support for load/store instructions on LE
From: Ravi Bangoria
Date: Tue Feb 14 2017 - 03:03:25 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 v2:
- Folded 2nd and 3rd patch of v1 into one patch, as suggested by Naveen
v1 link: https://www.mail-archive.com/linuxppc-dev@xxxxxxxxxxxxxxxx/msg110671.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/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