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From: Jiri Olsa <olsajiri@gmail.com>
Date: Tue, 21 May 2024 22:24:30 +0200
To: Jiri Olsa <olsajiri@gmail.com>
Cc: Alejandro Colomar <alx@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	linux-man@vger.kernel.org, x86@kernel.org, bpf@vger.kernel.org,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Borislav Petkov (AMD)" <bp@alien8.de>,
	Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
	"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	Deepak Gupta <debug@rivosinc.com>
Subject: Re: [PATCHv6 9/9] man2: Add uretprobe syscall page
Message-ID: <Zk0C_vm3T2L79-_W@krava>
References: <20240521104825.1060966-1-jolsa@kernel.org>
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 <ZkyKKwfhNZxrGWsa@krava>
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In-Reply-To: <ZkyKKwfhNZxrGWsa@krava>

On Tue, May 21, 2024 at 01:48:59PM +0200, Jiri Olsa wrote:
> On Tue, May 21, 2024 at 01:36:25PM +0200, Alejandro Colomar wrote:
> > Hi Jiri,
> > 
> > On Tue, May 21, 2024 at 12:48:25PM GMT, Jiri Olsa wrote:
> > > Adding man page for new uretprobe syscall.
> > > 
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > ---
> > >  man2/uretprobe.2 | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 50 insertions(+)
> > >  create mode 100644 man2/uretprobe.2
> > > 
> > > diff --git a/man2/uretprobe.2 b/man2/uretprobe.2
> > > new file mode 100644
> > > index 000000000000..690fe3b1a44f
> > > --- /dev/null
> > > +++ b/man2/uretprobe.2
> > > @@ -0,0 +1,50 @@
> > > +.\" Copyright (C) 2024, Jiri Olsa <jolsa@kernel.org>
> > > +.\"
> > > +.\" SPDX-License-Identifier: Linux-man-pages-copyleft
> > > +.\"
> > > +.TH uretprobe 2 (date) "Linux man-pages (unreleased)"
> > > +.SH NAME
> > > +uretprobe \- execute pending return uprobes
> > > +.SH SYNOPSIS
> > > +.nf
> > > +.B int uretprobe(void)
> > > +.fi
> > 
> > What header file provides this system call?
> 
> there's no header, it's used/called only by user space trampoline
> provided by kernel, it's not expected to be called by user
> 
> > 
> > > +.SH DESCRIPTION
> > > +The
> > > +.BR uretprobe ()
> > > +syscall is an alternative to breakpoint instructions for
> > > +triggering return uprobe consumers.
> > > +.P
> > > +Calls to
> > > +.BR uretprobe ()
> > > +suscall are only made from the user-space trampoline provided by the kernel.
> > 
> > s/suscall/system call/
> 
> ugh leftover sry
> 
> > 
> > > +Calls from any other place result in a
> > > +.BR SIGILL .
> > 
> > Maybe add an ERRORS section?
> > 
> > > +
> > 
> > We don't use blank lines; it causes a groff(1) warning, and other
> > problems.  Instead, use '.P'.
> > 
> > > +.SH RETURN VALUE
> > > +The
> > > +.BR uretprobe ()
> > > +syscall return value is architecture-specific.
> > > +
> > 
> > .P
> > 
> > > +.SH VERSIONS
> > > +This syscall is not specified in POSIX,
> > 
> > Redundant with "STANDARDS: None.".
> > 
> > > +and details of its behavior vary across systems.
> > 
> > Keep this.
> 
> ok
> 
> > 
> > > +.SH STANDARDS
> > > +None.
> > > +.SH HISTORY
> > > +TBD
> > > +.SH NOTES
> > > +The
> > > +.BR uretprobe ()
> > > +syscall was initially introduced for the x86_64 architecture where it was shown
> > > +to be faster than breakpoint traps. It might be extended to other architectures.
> > 
> > Please use semantic newlines.
> > 
> > $ MANWIDTH=72 man man-pages | sed -n '/Use semantic newlines/,/^$/p'
> >    Use semantic newlines
> >      In the source of a manual page, new sentences should be started on
> >      new lines, long sentences should be split  into  lines  at  clause
> >      breaks  (commas,  semicolons, colons, and so on), and long clauses
> >      should be split at phrase boundaries.  This convention,  sometimes
> >      known as "semantic newlines", makes it easier to see the effect of
> >      patches, which often operate at the level of individual sentences,
> >      clauses, or phrases.
> 

how about the change below?

thanks,
jirka


---
diff --git a/man/man2/uretprobe.2 b/man/man2/uretprobe.2
new file mode 100644
index 000000000000..959b7a47102b
--- /dev/null
+++ b/man/man2/uretprobe.2
@@ -0,0 +1,55 @@
+.\" Copyright (C) 2024, Jiri Olsa <jolsa@kernel.org>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.TH uretprobe 2 (date) "Linux man-pages (unreleased)"
+.SH NAME
+uretprobe \- execute pending return uprobes
+.SH SYNOPSIS
+.nf
+.B int uretprobe(void)
+.fi
+.SH DESCRIPTION
+The
+.BR uretprobe ()
+system call is an alternative to breakpoint instructions for triggering return
+uprobe consumers.
+.P
+Calls to
+.BR uretprobe ()
+system call are only made from the user-space trampoline provided by the kernel.
+Calls from any other place result in a
+.BR SIGILL .
+.SH RETURN VALUE
+The
+.BR uretprobe ()
+system call return value is architecture-specific.
+.SH ERRORS
+.BR SIGILL
+The
+.BR uretprobe ()
+system call was called by user.
+.SH VERSIONS
+Details of the
+.BR uretprobe ()
+system call behavior vary across systems.
+.SH STANDARDS
+None.
+.SH HISTORY
+TBD
+.SH NOTES
+The
+.BR uretprobe ()
+system call was initially introduced for the x86_64 architecture where it was shown
+to be faster than breakpoint traps.
+It might be extended to other architectures.
+.P
+The
+.BR uretprobe ()
+system call exists only to allow the invocation of return uprobe consumers.
+It should
+.B never
+be called directly.
+Details of the arguments (if any) passed to
+.BR uretprobe ()
+and the return value are architecture-specific.