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@vger.kernel.org/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 -- 1.8.3.1
