From: Dave Hansen <dave.hansen@intel.com>
To: Nadav Amit <nadav.amit@gmail.com>, Borislav Petkov <bp@alien8.de>
Cc: Jiri Slaby <jirislaby@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] x86/lib: Do not use local symbols with SYM_CODE_START_LOCAL()
Date: Fri, 26 May 2023 14:17:20 -0700 [thread overview]
Message-ID: <e6cd1909-2776-28d2-ccc0-4b3d2d09e9ce@intel.com> (raw)
In-Reply-To: <D63AB9E6-BA52-4E24-B8EF-C7B9DB1595CC@gmail.com>
On 5/26/23 14:10, Nadav Amit wrote:
>>> I did not ask to make them global. Just to keep them as local after
>>> linkage in the executable, like all other functions in the kernel.
>> Ok, not global. But local and present in the symbol table:
>>
>> 105185: ffffffff81b89330 17 NOTYPE LOCAL DEFAULT 1 bad_get_user_clac
>>
>> And again, this helps how exactly?
> Allowing debuggers, tracers, disassemblers and instrumentation tools to
> work the same way they work as they work with any other piece of code in
> the kernel.
>
> I personally work on code instrumentation and this makes my life hard for
> no good reason.
>
> [ Perhaps the question should go the other way around: why addresses of
> code in these functions should not be mapped to any symbol? ]
Nadav, is there a chance you could give us a real-life example of how
this affects you as an end user? What's a specific tool that you were
using or a specific problem that you were trying to solve where these
local symbols caused a problem? How would the global symbol have helped?
I can certainly _imagine_ some, but I'm curious what you saw that
prompted you to send this patch.
next prev parent reply other threads:[~2023-05-26 21:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-25 18:42 [PATCH v2] x86/lib: Do not use local symbols with SYM_CODE_START_LOCAL() Nadav Amit
2023-05-25 19:05 ` Dave Hansen
2023-05-25 19:39 ` Nadav Amit
2023-05-26 6:24 ` Jiri Slaby
2023-05-26 15:53 ` Borislav Petkov
2023-05-26 17:29 ` Nadav Amit
2023-05-26 20:45 ` Borislav Petkov
2023-05-26 21:10 ` Nadav Amit
2023-05-26 21:17 ` Dave Hansen [this message]
2023-05-26 21:55 ` Nadav Amit
2023-05-27 7:23 ` Borislav Petkov
2023-05-27 9:17 ` Nadav Amit
2023-05-27 12:29 ` Borislav Petkov
2023-05-27 13:09 ` Nadav Amit
2023-06-02 0:53 ` Nadav Amit
2023-06-02 8:59 ` [tip: x86/misc] x86/lib: Make get/put_user() exception handling a visible symbol tip-bot2 for Nadav Amit
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=e6cd1909-2776-28d2-ccc0-4b3d2d09e9ce@intel.com \
--to=dave.hansen@intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=jirislaby@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=nadav.amit@gmail.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/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