Re: [PATCH 0/4] arm64: kgdb/kdb: Fix single-step debugging issues

From: "liwei (GF)" <liwei391@huawei.com>
To: Doug Anderson <dianders@chromium.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>,
	Jason Wessel <jason.wessel@windriver.com>,
	Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	David Miller <davem@davemloft.net>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>, <liwei1412@163.com>
Subject: Re: [PATCH 0/4] arm64: kgdb/kdb: Fix single-step debugging issues
Date: Sat, 16 May 2020 16:20:35 +0800	[thread overview]
Message-ID: <a20ee677-495b-9336-a329-eabd50dd1cad@huawei.com> (raw)
In-Reply-To: <CAD=FV=Xv6xgj_M9tYjHzmW4UZD2RdH2c5=dagNybSkdfBabYZw@mail.gmail.com>

Hi Douglas,

On 2020/5/14 8:34, Doug Anderson wrote:
> Hi,
> 
> On Sat, May 9, 2020 at 6:49 AM Wei Li <liwei391@huawei.com> wrote:
>>
>> This patch set is to fix several issues of single-step debugging
>> in kgdb/kdb on arm64.
>>
>> It seems that these issues have been shelved a very long time,
>> but i still hope to solve them, as the single-step debugging
>> is an useful feature.
>>
>> Note:
>> Based on patch "arm64: cacheflush: Fix KGDB trap detection",
>> https://www.spinics.net/lists/arm-kernel/msg803741.html
>>
>> Wei Li (4):
>>   arm64: kgdb: Fix single-step exception handling oops
>>   arm64: Extract kprobes_save_local_irqflag() and
>>     kprobes_restore_local_irqflag()
>>   arm64: kgdb: Fix single-stepping into the irq handler wrongly
>>   arm64: kgdb: Set PSTATE.SS to 1 to reenable single-step
>>
>>  arch/arm64/include/asm/debug-monitors.h |  6 ++++++
>>  arch/arm64/kernel/debug-monitors.c      | 28 ++++++++++++++++++++++++-
>>  arch/arm64/kernel/kgdb.c                | 16 +++++++++++---
>>  arch/arm64/kernel/probes/kprobes.c      | 28 ++-----------------------
>>  4 files changed, 48 insertions(+), 30 deletions(-)
> 
> Just an overall note that I'm very happy that you posted this patch
> series!  It's always been a thorn in my side that stepping and
> breakpoints were so broken on arm64 and I'm really excited that you're
> fixing them.  Now I'll have to get in the habit of using kgdb for more
> than just debugging crashes and maybe I can use it more for exploring
> how functions work more.  :-)
> > I'll also note that with your patch series I'm even seeing the "call"
> feature of gdb working now.  That has always been terribly broken for
> me.
> 
Thanks for reviewing and testing this series.
Enjoy exploring the kernel with kgdb/kdb! :-)

Thanks,
Wei