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Date:   Mon, 19 Aug 2019 13:53:21 +0100
From:   Mark Rutland <mark.rutland@arm.com>
To:     Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] arm64: KPROBES_ON_FTRACE
Message-ID: <20190819125321.GA9927@lakrids.cambridge.arm.com>
References: <20190819192422.5ed79702@xhacker.debian>
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Hi,

On Mon, Aug 19, 2019 at 11:35:27AM +0000, Jisheng Zhang wrote:
> Implement KPROBES_ON_FTRACE for arm64.

It would be very helpful if the cover letter could explain what
KPROBES_ON_FTRACE is, and why it is wanted.

It's not clear to me whether this is enabling new functionality for
kprobes via ftrace, or whether this is an optimization for kprobes using
ftrace under the hood.

Thanks,
Mark.

> 
> Applied after FTRACE_WITH_REGS:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2019-August/674404.html
> 
> Jisheng Zhang (4):
>   kprobes: adjust kprobe addr for KPROBES_ON_FTRACE
>   kprobes/x86: use instruction_pointer and instruction_pointer_set
>   kprobes: move kprobe_ftrace_handler() from x86 and make it weak
>   arm64: implement KPROBES_ON_FTRACE
> 
>  arch/arm64/Kconfig                |  1 +
>  arch/arm64/kernel/probes/Makefile |  1 +
>  arch/arm64/kernel/probes/ftrace.c | 16 +++++++++++
>  arch/x86/kernel/kprobes/ftrace.c  | 43 ----------------------------
>  kernel/kprobes.c                  | 47 +++++++++++++++++++++++++++++++
>  5 files changed, 65 insertions(+), 43 deletions(-)
>  create mode 100644 arch/arm64/kernel/probes/ftrace.c
> 
> -- 
> 2.23.0.rc1
>