Date: Thu, 3 Nov 2016 12:33:18 +0530
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
        lsorense@csclub.uwaterloo.ca, oohall@gmail.com, ast@kernel.org,
        chris@distroguy.com, aneesh.kumar@linux.vnet.ibm.com,
        bsingharora@gmail.com, anton@samba.org, paul.gortmaker@windriver.com,
        bauerman@linux.vnet.ibm.com, viro@zeniv.linux.org.uk,
        christophe.leroy@c-s.fr, duwe@lst.de, oss@buserror.net
Subject: Re: [PATCH 0/3] powerpc: Emulation support for load/store
 instructions on LE
References: <1478076783-2872-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com>
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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 <naveen.n.rao@linux.vnet.ibm.com>

Thanks,
Naveen