public inbox for linux-riscv@lists.infradead.org
 help / color / mirror / Atom feed
From: "liaochang (A)" <liaochang1@huawei.com>
To: "Björn Töpel" <bjorn@kernel.org>,
	"Chen Guokai" <chenguokai17@mails.ucas.ac.cn>,
	paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, rostedt@goodmis.org, mingo@redhat.com,
	sfr@canb.auug.org.au
Cc: <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 1/9] riscv/kprobe: Prepare the skeleton to implement RISCV OPTPROBES feature
Date: Wed, 4 Jan 2023 16:34:26 +0800	[thread overview]
Message-ID: <c5bdf7af-112e-e92c-7df0-8bc8a652bcd8@huawei.com> (raw)
In-Reply-To: <87wn64vmoq.fsf@all.your.base.are.belong.to.us>



在 2023/1/3 2:03, Björn Töpel 写道:
> Chen Guokai <chenguokai17@mails.ucas.ac.cn> writes:
> 
>> From: Liao Chang <liaochang1@huawei.com>
>>
>> Prepare skeleton to implement optimized kprobe on RISCV, it is consist
>> of Makfile, Kconfig and some architecture specific files: kprobe.h and
>> opt.c opt.c include some macro, type definition and functions required
>> by kprobe framework, opt_trampoline.S provide a piece of assembly code
>> template used to construct the detour buffer as the target of long jump
>> instruction(s) for each optimzed kprobe.
> 
> This is pretty much just reiterating what diff-stat says. Please try to
> explain why a certain change is done, instead of what. What is already
> in the patch.

Thanks for your suggestion, i will explain further in next revision.

> 
>> Since the jump range of PC-relative instruction JAL is +/-2M, that is
>> too small to reach the detour buffer, hence the foudamental idea to
>> address OPTPROBES on RISCV is replace 'EBREAK' with 'AUIPC/JALR'. which
>> means it needs to clobber one more instruction beside the kprobe
>> instruction, furthermore, RISCV supports hybird RVI and RVC in single
>> kernel binary, so in theory a pair of 'AUIPC/JALR' is about to clobber
>> 10 bytes(3 RVC and 1 RVI, 2 bytes is padding for alignment) at worst
>> case. The second hardsome problem is looking for one integer register as
>> the destination of 'AUIPC/JALR' without any side-effect.
> 
> There are a number of spelling errors, please use a spellchecker and if
> you reference a file (e.g. Makefile), make sure it is correctly spelled
> out.
> 
> The comments above applies to all the commit messages of this series.

Thanks for reviewing, i will correct these spelling errors.

> 
> 
> Björn

-- 
BR,
Liao, Chang

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2023-01-04  8:44 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-24 11:43 [PATCH v5 0/9] Add OPTPROBES feature on RISCV Chen Guokai
2022-12-24 11:43 ` [PATCH v5 1/9] riscv/kprobe: Prepare the skeleton to implement RISCV OPTPROBES feature Chen Guokai
2023-01-02 18:03   ` Björn Töpel
2023-01-04  8:34     ` liaochang (A) [this message]
2022-12-24 11:43 ` [PATCH v5 2/9] riscv/kprobe: Allocate detour buffer from module area Chen Guokai
2022-12-24 11:43 ` [PATCH v5 3/9] riscv/kprobe: Prepare the skeleton to prepare optimized kprobe Chen Guokai
2023-01-02 18:03   ` Björn Töpel
2023-01-04  8:34     ` liaochang (A)
2023-01-04  8:54       ` Björn Töpel
2023-01-03  8:27   ` Björn Töpel
2023-01-04  8:34     ` liaochang (A)
2022-12-24 11:43 ` [PATCH v5 4/9] riscv/kprobe: Add common RVI and RVC instruction decoder code Chen Guokai
2023-01-02 18:03   ` Björn Töpel
2023-01-04  8:35     ` liaochang (A)
2023-01-04  8:57       ` Björn Töpel
2022-12-24 11:43 ` [PATCH v5 5/9] riscv/kprobe: Search free register(s) to clobber for 'AUIPC/JALR' Chen Guokai
2022-12-24 11:43 ` [PATCH v5 6/9] riscv/kprobe: Add code to check if kprobe can be optimized Chen Guokai
2023-01-02 18:04   ` Björn Töpel
2023-01-04  8:35     ` liaochang (A)
2022-12-24 11:43 ` [PATCH v5 7/9] riscv/kprobe: Prepare detour buffer for optimized kprobe Chen Guokai
2023-01-02 18:04   ` Björn Töpel
2023-01-04  8:35     ` liaochang (A)
2023-01-04  9:12       ` Björn Töpel
2023-01-05  0:46         ` liaochang (A)
2022-12-24 11:43 ` [PATCH v5 8/9] riscv/kprobe: Patch AUIPC/JALR pair to optimize kprobe Chen Guokai
2022-12-24 11:43 ` [PATCH v5 9/9] riscv/kprobe: Search free registers from unused caller-saved ones Chen Guokai
2023-01-02 18:04   ` Björn Töpel
2023-01-04  8:35     ` liaochang (A)
2023-01-02 18:02 ` [PATCH v5 0/9] Add OPTPROBES feature on RISCV Björn Töpel
2023-01-04  8:30   ` Xim
2023-01-04  8:45     ` Björn Töpel
2023-01-04  8:34   ` liaochang (A)
2023-01-04  8:53     ` Björn Töpel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=c5bdf7af-112e-e92c-7df0-8bc8a652bcd8@huawei.com \
    --to=liaochang1@huawei.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=bjorn@kernel.org \
    --cc=chenguokai17@mails.ucas.ac.cn \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=mingo@redhat.com \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=rostedt@goodmis.org \
    --cc=sfr@canb.auug.org.au \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox