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From: "Björn Töpel" <bjorn@kernel.org>
To: 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,
	liaochang1@huawei.com,
	Chen Guokai <chenguokai17@mails.ucas.ac.cn>
Subject: Re: [PATCH v6 06/13] riscv/kprobe: Add code to check if kprobe can be optimized
Date: Wed, 01 Feb 2023 14:30:01 +0100	[thread overview]
Message-ID: <87wn51tsx2.fsf@all.your.base.are.belong.to.us> (raw)
In-Reply-To: <20230127130541.1250865-7-chenguokai17@mails.ucas.ac.cn>

Chen Guokai <chenguokai17@mails.ucas.ac.cn> writes:

> From: Liao Chang <liaochang1@huawei.com>
>
> For the RVI and RVC hybrid encoding kernel, although AUIPC/JALR just
> occupy 8 bytes space, the patched code is 10 bytes at the worst case
> to ensure no RVI is truncated, so to check if kprobe satisfies the
> requirement of jump optimization, it has to find out an instruction
> window large enough to patch AUIPC/JALR(and padding C.NOP), and ensure
> no instruction nearby jumps into the patching window.
>
> Besides that, this series does not support the simulation of pc-relative
> instruction in optprobe handler yet, so the patching window should not
> includes pc-relative instruction.
>
> Signed-off-by: Liao Chang <liaochang1@huawei.com>
> Co-developed-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
> Signed-off-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>

Reviewed-by: Björn Töpel <bjorn@kernel.org>

_______________________________________________
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: "Björn Töpel" <bjorn@kernel.org>
To: 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,
	liaochang1@huawei.com,
	Chen Guokai <chenguokai17@mails.ucas.ac.cn>
Subject: Re: [PATCH v6 06/13] riscv/kprobe: Add code to check if kprobe can be optimized
Date: Wed, 01 Feb 2023 14:30:01 +0100	[thread overview]
Message-ID: <87wn51tsx2.fsf@all.your.base.are.belong.to.us> (raw)
In-Reply-To: <20230127130541.1250865-7-chenguokai17@mails.ucas.ac.cn>

Chen Guokai <chenguokai17@mails.ucas.ac.cn> writes:

> From: Liao Chang <liaochang1@huawei.com>
>
> For the RVI and RVC hybrid encoding kernel, although AUIPC/JALR just
> occupy 8 bytes space, the patched code is 10 bytes at the worst case
> to ensure no RVI is truncated, so to check if kprobe satisfies the
> requirement of jump optimization, it has to find out an instruction
> window large enough to patch AUIPC/JALR(and padding C.NOP), and ensure
> no instruction nearby jumps into the patching window.
>
> Besides that, this series does not support the simulation of pc-relative
> instruction in optprobe handler yet, so the patching window should not
> includes pc-relative instruction.
>
> Signed-off-by: Liao Chang <liaochang1@huawei.com>
> Co-developed-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
> Signed-off-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>

Reviewed-by: Björn Töpel <bjorn@kernel.org>

  reply	other threads:[~2023-02-01 13:30 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-27 13:05 [PATCH v6 00/13] Add OPTPROBES feature on RISCV Chen Guokai
2023-01-27 13:05 ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 01/13] riscv/kprobe: Prepare the skeleton to implement RISCV OPTPROBES Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 02/13] riscv/kprobe: Allocate detour buffer from module region Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 03/13] riscv/kprobe: Add skeleton for preparing optimized kprobe Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 04/13] riscv/kprobe: Add common RVI and RVC instruction decoder code Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:29   ` Björn Töpel
2023-02-01 13:29     ` Björn Töpel
2023-02-02 10:16   ` Conor Dooley
2023-02-02 10:16     ` Conor Dooley
2023-01-27 13:05 ` [PATCH v6 05/13] riscv/kprobe: Introduce free register(s) searching algorithm Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 06/13] riscv/kprobe: Add code to check if kprobe can be optimized Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:30   ` Björn Töpel [this message]
2023-02-01 13:30     ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 07/13] riscv/kprobe: Prepare detour buffer for optimized kprobe Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:30   ` Björn Töpel
2023-02-01 13:30     ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 08/13] riscv/kprobe: Patch AUIPC/JALR pair to optimize kprobe Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:31   ` Björn Töpel
2023-02-01 13:31     ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 09/13] riscv/kprobe: Search free registers from unused caller-saved ones Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:31   ` Björn Töpel
2023-02-01 13:31     ` Björn Töpel
2023-02-02  9:08   ` Conor Dooley
2023-02-02  9:08     ` Conor Dooley
2023-01-27 13:05 ` [PATCH v6 10/13] riscv/kprobe: Add instruction boundary check for RVI/RVC hybrid kernel Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-27 13:05 ` [PATCH v6 11/13] riscv/kprobe: Fix instruction simulation of JALR Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-31 12:51   ` Björn Töpel
2023-01-31 12:51     ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 12/13] riscv/kprobe: Move exception related symbols to .kprobe_blacklist Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-02-01 13:30   ` Björn Töpel
2023-02-01 13:30     ` Björn Töpel
2023-01-27 13:05 ` [PATCH v6 13/13] selftest/kprobes: Add testcase for kprobe SYM[+offs] Chen Guokai
2023-01-27 13:05   ` Chen Guokai
2023-01-30 12:31 ` [PATCH v6 00/13] Add OPTPROBES feature on RISCV Björn Töpel
2023-01-30 12:31   ` Björn Töpel
2023-01-30 14:38   ` Xim
2023-01-30 14:38     ` Xim
2023-04-26 18:01     ` Palmer Dabbelt
2023-04-26 18:01       ` Palmer Dabbelt
2023-02-01 13:29 ` Björn Töpel
2023-02-01 13:29   ` Björn Töpel

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