|| ||Tom Tromey <tromey-AT-redhat.com> |
|| ||Linus Torvalds <torvalds-AT-linux-foundation.org> |
|| ||Re: linux-next: add utrace tree |
|| ||Mon, 25 Jan 2010 14:05:54 -0700|
|| ||Stephen Rothwell <sfr-AT-canb.auug.org.au>,
Kyle Moffett <kyle-AT-moffetthome.net>,
Peter Zijlstra <a.p.zijlstra-AT-chello.nl>,
Peter Zijlstra <peterz-AT-infradead.org>,
Fr??d??ric Weisbecker <fweisbec-AT-gmail.com>,
Oleg Nesterov <oleg-AT-redhat.com>, Steven Rostedt <rostedt-AT-goodmis.org>,
Arnaldo Carvalho de Melo <acme-AT-redhat.com>,
"Frank Ch. Eigler" <fche-AT-redhat.com>, linux-next-AT-vger.kernel.org,
"H. Peter Anvin" <hpa-AT-zytor.com>, utrace-devel-AT-redhat.com,
Thomas Gleixner <tglx-AT-linutronix.de>|
|| ||Article, Thread
>>>>> "Linus" == Linus Torvalds <firstname.lastname@example.org> writes:
Linus> No. There is absolutely _no_ reason to believe that gdb et al would ever
Linus> delete the ptrace interfaces anyway.
Yes, in GDB we approximately never delete anything.
Nevertheless, if the Linux kernel were to present a new user-space API,
and if it had an advantage over ptrace, then we would port GDB to use
it. There are other platforms where, IIRC, we now use some /proc thing
instead of ptrace.
There are definitely things we would like from such an API. Here's a
few I can think of immediately, there are probably others.
* Use an fd, not SIGCHLD+wait, to report inferior state changes to gdb.
Internally we're already using a self-pipe to integrate this into
gdb's main loop. Relatedly, don't mess with the inferior's parentage.
* Support "displaced stepping" in the kernel; I think this would improve
performance when debugging in non-stop mode.
* Support some kind of breakpoint expression in the kernel; this would
improve performance of conditional breakpoints. Perhaps the existing
gdb agent expressions could be used.
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