On Sun, 21 Apr 2024 21:42:06 +0200 Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > Adding man page for new uretprobe syscall. > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> > --- > man2/uretprobe.2 | 40 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > create mode 100644 man2/uretprobe.2 > > diff --git a/man2/uretprobe.2 b/man2/uretprobe.2 > new file mode 100644 > index 000000000000..c0343a88bb57 > --- /dev/null > +++ b/man2/uretprobe.2 > @@ -0,0 +1,40 @@ > +.\" Copyright (C) 2024, Jiri Olsa <jolsa@xxxxxxxxxx> > +.\" > +.\" 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 > +On x86_64 architecture the kernel is using uretprobe syscall to trigger > +uprobe return probe consumers instead of using standard breakpoint instruction. > +The reason is that it's much faster to do syscall than breakpoint trap > +on x86_64 architecture. Do we specify the supported architecture as this? Currently it is supported only on x86-64, but it could be extended later, right? This should be just noted as NOTES. Something like "This syscall is initially introduced on x86-64 because a syscall is faster than a breakpoint trap on it. But this will be extended to the architectures whose syscall is faster than breakpoint trap." Thank you, > + > +The uretprobe syscall is not supposed to be called directly by user, it's allowed > +to be invoked only through user space trampoline provided by kernel. > +When called from outside of this trampoline, the calling process will receive > +.BR SIGILL . > + > +.SH RETURN VALUE > +.BR uretprobe() > +return value is specific for given architecture. > + > +.SH VERSIONS > +This syscall is not specified in POSIX, > +and details of its behavior vary across systems. > +.SH STANDARDS > +None. > +.SH NOTES > +.BR uretprobe() > +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 specific for given architecture. > -- > 2.44.0 > -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
