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From: Steven Rostedt <rostedt@goodmis.org>
To: "Wangshaobo (bobo)" <bobo.shaobowang@huawei.com>
Cc: <cj.chengjian@huawei.com>, <huawei.libin@huawei.com>,
	<xiexiuqi@huawei.com>, <liwei391@huawei.com>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <catalin.marinas@arm.com>,
	<will@kernel.org>, <mark.rutland@arm.com>,
	<zengshun.wu@outlook.com>
Subject: Re: [RFC PATCH -next v2 0/4] arm64/ftrace: support dynamic trampoline
Date: Thu, 21 Apr 2022 08:37:58 -0400	[thread overview]
Message-ID: <20220421083758.37b239a4@gandalf.local.home> (raw)
In-Reply-To: <5ddc2722-4489-f66d-552d-1f4c755b5d30@huawei.com>

On Thu, 21 Apr 2022 09:13:01 +0800
"Wangshaobo (bobo)" <bobo.shaobowang@huawei.com> wrote:

> Not yet, Steve, ftrace_location() looks has no help to find a right 
> rec->ip in our case,
> 
> ftrace_location() can find a right rec->ip when input ip is in the range 
> between
> 
> sym+0 and sym+$end, but our question is how to  identify rec->ip from 
> __mcount_loc,

Are you saying that the "ftrace location" is not between sym+0 and sym+$end?

> 
> this changed the patchable entry before bti to after in gcc:
> 
>     [1] https://reviews.llvm.org/D73680
> 
> gcc tells the place of first nop of the 5 NOPs when using 
> -fpatchable-function-entry=5,3,
> 
> but not tells the first nop after bti, so we don't know how to adjust 
> our rec->ip for ftrace.

OK, so I do not understand how the compiler is injecting bti with mcount
calls, so I'll just walk away for now ;-)

-- Steve

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  reply	other threads:[~2022-04-21 12:39 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-16 10:01 [RFC PATCH -next v2 0/4] arm64/ftrace: support dynamic trampoline Wang ShaoBo
2022-03-16 10:01 ` [RFC PATCH -next v2 1/4] arm64: introduce aarch64_insn_gen_load_literal Wang ShaoBo
2022-03-16 10:01 ` [RFC PATCH -next v2 2/4] arm64/ftrace: introduce ftrace dynamic trampoline entrances Wang ShaoBo
2022-03-16 10:01 ` [RFC PATCH -next v2 3/4] arm64/ftrace: support dynamically allocated trampolines Wang ShaoBo
2022-04-21 13:10   ` Mark Rutland
2022-04-21 14:06     ` Steven Rostedt
2022-04-21 14:08       ` Steven Rostedt
2022-04-21 15:14       ` Mark Rutland
2022-04-21 15:42         ` Steven Rostedt
2022-04-21 16:27           ` Mark Rutland
2022-04-21 17:06             ` Steven Rostedt
2022-04-22 10:12               ` Mark Rutland
2022-04-22 15:45                 ` Steven Rostedt
2022-04-22 17:27                   ` Mark Rutland
2022-04-26  8:47                     ` Masami Hiramatsu
2022-05-04 10:24                       ` Mark Rutland
2022-05-05  3:15                         ` Masami Hiramatsu
2022-05-09 18:22                           ` Steven Rostedt
2022-05-10  9:10                             ` Masami Hiramatsu
2022-05-10 14:44                               ` Steven Rostedt
2022-05-11 14:34                                 ` Masami Hiramatsu
2022-05-11 15:12                                   ` Steven Rostedt
2022-05-12 12:02                                     ` Masami Hiramatsu
2022-05-12 13:50                                       ` Steven Rostedt
2022-05-25 12:17                                       ` Mark Rutland
2022-05-25 13:43                                         ` Steven Rostedt
2022-05-25 17:12                                           ` Mark Rutland
2022-05-30  1:03                                         ` Masami Hiramatsu
2022-05-30 12:38                                           ` Jiri Olsa
2022-05-31  1:00                                             ` Masami Hiramatsu
2022-05-04 12:43               ` Mark Rutland
2022-05-05  2:57             ` Wangshaobo (bobo)
2022-05-25 12:27               ` Mark Rutland
2022-04-27  8:54       ` Wangshaobo (bobo)
2022-03-16 10:01 ` [RFC PATCH -next v2 4/4] arm64/ftrace: implement long jump for dynamic trampolines Wang ShaoBo
2022-04-21 13:47   ` Mark Rutland
2022-03-16 14:29 ` [RFC PATCH -next v2 0/4] arm64/ftrace: support dynamic trampoline Steven Rostedt
2022-04-20 18:11 ` Steven Rostedt
2022-04-21  1:13   ` Wangshaobo (bobo)
2022-04-21 12:37     ` Steven Rostedt [this message]
2022-05-25 12:45       ` Mark Rutland
2022-05-25 13:58         ` Steven Rostedt
2022-05-25 17:26           ` Mark Rutland
2022-04-21 12:53 ` Mark Rutland

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