All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] riscv: code patching only works on !XIP_KERNEL
Date: Tue, 11 May 2021 18:10:33 +0800	[thread overview]
Message-ID: <20210511181033.580c1eba@xhacker.debian> (raw)
In-Reply-To: <CAM4kBBJqF=AxTu50PF=EshLSyqn0=yeC2dwf4JJj_Grsi_Tccg@mail.gmail.com>

On Mon, 10 May 2021 20:19:30 +0200 Vitaly Wool <vitaly.wool@konsulko.com> wrote:


> 
> 
> On Mon, May 10, 2021 at 6:35 PM Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> >
> > From: Jisheng Zhang <jszhang@kernel.org>
> >
> > Some features which need code patching such as KPROBES, DYNAMIC_FTRACE
> > KGDB can only work on !XIP_KERNEL. Add dependencies for these features
> > that rely on code patching.  
> 
> Since we can define extra RW sections to place some tiny code bits in

I knew this discussion on maillist recently, that's the
reason why ERRATA_ALTERNATIVE related part isn't touched

> RAM, I would suggest that you hold back this patch for a while.
> I am not going to support the idea of e. g. compiling KGDB support
> into a XIP kernel, but disabling the whole HAVE_ARCH_JUMP_LABEL is
> hardly the way to go.
> 

I'm not sure whether the solution "extra RW sections to place some tiny code
bits" can work for JUMP_LABEL or not. But obviously, in JUMP_LABEL users
such as static keys, the patching is taken on the .text section unless
patching the common implementation kernel/jump_label.c. IMHO it's impossible.

However, I can hold back this patch for a while as you suggested.

Thanks

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

WARNING: multiple messages have this Message-ID (diff)
From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] riscv: code patching only works on !XIP_KERNEL
Date: Tue, 11 May 2021 18:10:33 +0800	[thread overview]
Message-ID: <20210511181033.580c1eba@xhacker.debian> (raw)
In-Reply-To: <CAM4kBBJqF=AxTu50PF=EshLSyqn0=yeC2dwf4JJj_Grsi_Tccg@mail.gmail.com>

On Mon, 10 May 2021 20:19:30 +0200 Vitaly Wool <vitaly.wool@konsulko.com> wrote:


> 
> 
> On Mon, May 10, 2021 at 6:35 PM Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> >
> > From: Jisheng Zhang <jszhang@kernel.org>
> >
> > Some features which need code patching such as KPROBES, DYNAMIC_FTRACE
> > KGDB can only work on !XIP_KERNEL. Add dependencies for these features
> > that rely on code patching.  
> 
> Since we can define extra RW sections to place some tiny code bits in

I knew this discussion on maillist recently, that's the
reason why ERRATA_ALTERNATIVE related part isn't touched

> RAM, I would suggest that you hold back this patch for a while.
> I am not going to support the idea of e. g. compiling KGDB support
> into a XIP kernel, but disabling the whole HAVE_ARCH_JUMP_LABEL is
> hardly the way to go.
> 

I'm not sure whether the solution "extra RW sections to place some tiny code
bits" can work for JUMP_LABEL or not. But obviously, in JUMP_LABEL users
such as static keys, the patching is taken on the .text section unless
patching the common implementation kernel/jump_label.c. IMHO it's impossible.

However, I can hold back this patch for a while as you suggested.

Thanks

  reply	other threads:[~2021-05-11 12:49 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 16:28 [PATCH] riscv: code patching only works on !XIP_KERNEL Jisheng Zhang
2021-05-10 16:28 ` Jisheng Zhang
2021-05-10 18:19 ` Vitaly Wool
2021-05-10 18:19   ` Vitaly Wool
2021-05-11 10:10   ` Jisheng Zhang [this message]
2021-05-11 10:10     ` Jisheng Zhang
2021-05-22 17:15   ` Palmer Dabbelt
2021-05-22 17:15     ` Palmer Dabbelt
2021-05-24 19:32     ` Vitaly Wool
2021-05-24 19:32       ` Vitaly Wool
2021-06-08  7:24       ` Jisheng Zhang
2021-06-08  7:24         ` Jisheng Zhang
2021-06-08  7:50         ` Vitaly Wool
2021-06-08  7:50           ` Vitaly Wool
2021-06-08  8:14           ` Jisheng Zhang
2021-06-08  8:14             ` Jisheng Zhang
2021-06-11  0:51             ` Palmer Dabbelt
2021-06-11  0:51               ` Palmer Dabbelt

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=20210511181033.580c1eba@xhacker.debian \
    --to=jisheng.zhang@synaptics.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=jszhang3@mail.ustc.edu.cn \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=vitaly.wool@konsulko.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.