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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 10:10 UTC|newest]

Thread overview: 9+ 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 18:19 ` Vitaly Wool
2021-05-11 10:10   ` Jisheng Zhang [this message]
2021-05-22 17:15   ` Palmer Dabbelt
2021-05-24 19:32     ` Vitaly Wool
2021-06-08  7:24       ` Jisheng Zhang
2021-06-08  7:50         ` Vitaly Wool
2021-06-08  8:14           ` Jisheng Zhang
2021-06-11  0:51             ` Palmer Dabbelt

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