linux-kernel - Re: [RFC PATCH] riscv: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 21 Mar 2024 10:49:39 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Mark Rutland <mark.rutland@....com>
Cc: "Bj\"orn T\"opel" <bjorn@...nel.org>, Puranjay Mohan
 <puranjay12@...il.com>, Paul Walmsley <paul.walmsley@...ive.com>, Palmer
 Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, Masami
 Hiramatsu <mhiramat@...nel.org>, Sami Tolvanen <samitolvanen@...gle.com>,
 Guo Ren <guoren@...nel.org>, Ley Foon Tan <leyfoon.tan@...rfivetech.com>,
 Deepak Gupta <debug@...osinc.com>, Sia Jee Heng
 <jeeheng.sia@...rfivetech.com>, "Bj\"orn T\"opel" <bjorn@...osinc.com>,
 Song Shuai <suagrfillet@...il.com>, Cl'ement L'eger <cleger@...osinc.com>,
 Al Viro <viro@...iv.linux.org.uk>, Jisheng Zhang <jszhang@...nel.org>,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-trace-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] riscv: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS

On Tue, 12 Mar 2024 13:42:28 +0000
Mark Rutland <mark.rutland@....com> wrote:

> > It would be interesting to see how the per-call performance would
> > improve on x86 with CALL_OPS! ;-)  
> 
> Heh. ;)

But this would require adding -fpatchable-function-entry on x86, which
would increase the size of text, which could possibly have a performance
regression when tracing is disabled.

I'd have no problem if someone were to implement it, but there's a strict
requirement that it does not slow down the system when tracing is disabled.
As tracing is a second class citizen compared to the rest of the kernel.

-- Steve