From: peterz at infradead.org (Peter Zijlstra)
Subject: [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation
Date: Tue, 30 Apr 2019 15:56:02 +0200 [thread overview]
Message-ID: <20190430135602.GD2589@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAHk-=wg1QPz0m+7jnVcjQgkySUQLzAXE8_PZARV-vWYK27LB=w@mail.gmail.com>
On Mon, Apr 29, 2019 at 01:07:33PM -0700, Linus Torvalds wrote:
> On Mon, Apr 29, 2019 at 12:24 PM Andy Lutomirski <luto at kernel.org> wrote:
> > > Side note: we *already* depend on sti shadow working in other parts of the kernel, namely sti->iret.
> >
> > Where? STI; IRET would be nuts.
>
> Sorry, not 'sti;iret' but 'sti;sysexit'
>
> > before commit 4214a16b02971c60960afd675d03544e109e0d75
> > x86/asm/entry/64/compat: Use SYSRETL to return from compat mode SYSENTER
> >
> > we did sti; sysxit, but, when we discussed this, I don't recall anyone
> > speaking up in favor of the safely of the old code.
>
> We still have that sti sysexit in the 32-bit code.
We also have both: "STI; HLT" and "STI; MWAIT" where we rely on the STI
shadow. Getting an NMI in between shouldn't hurt too much, but if that
in turn can lead to an actual interrupt happening, we're up some creek
without no paddle.
Most moden systems don't use either anymore though. As
mwait_idle_with_hints() relies on MWAIT ECX[0]=1 to allow MWAIT to wake
from pending interrupts.
WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra)
Subject: [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation
Date: Tue, 30 Apr 2019 15:56:02 +0200 [thread overview]
Message-ID: <20190430135602.GD2589@hirez.programming.kicks-ass.net> (raw)
Message-ID: <20190430135602.wjZQq7bBaiGZGMNAsRLAU6uIBvbbM0BTUj6cwSusvg8@z> (raw)
In-Reply-To: <CAHk-=wg1QPz0m+7jnVcjQgkySUQLzAXE8_PZARV-vWYK27LB=w@mail.gmail.com>
On Mon, Apr 29, 2019@01:07:33PM -0700, Linus Torvalds wrote:
> On Mon, Apr 29, 2019@12:24 PM Andy Lutomirski <luto@kernel.org> wrote:
> > > Side note: we *already* depend on sti shadow working in other parts of the kernel, namely sti->iret.
> >
> > Where? STI; IRET would be nuts.
>
> Sorry, not 'sti;iret' but 'sti;sysexit'
>
> > before commit 4214a16b02971c60960afd675d03544e109e0d75
> > x86/asm/entry/64/compat: Use SYSRETL to return from compat mode SYSENTER
> >
> > we did sti; sysxit, but, when we discussed this, I don't recall anyone
> > speaking up in favor of the safely of the old code.
>
> We still have that sti sysexit in the 32-bit code.
We also have both: "STI; HLT" and "STI; MWAIT" where we rely on the STI
shadow. Getting an NMI in between shouldn't hurt too much, but if that
in turn can lead to an actual interrupt happening, we're up some creek
without no paddle.
Most moden systems don't use either anymore though. As
mwait_idle_with_hints() relies on MWAIT ECX[0]=1 to allow MWAIT to wake
from pending interrupts.
next prev parent reply other threads:[~2019-04-30 13:56 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-27 10:06 [PATCH 0/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation nstange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member nstange
2019-04-27 10:06 ` Nicolai Stange
2019-04-28 17:41 ` luto
2019-04-28 17:41 ` Andy Lutomirski
2019-04-28 17:51 ` rostedt
2019-04-28 17:51 ` Steven Rostedt
2019-04-28 18:08 ` luto
2019-04-28 18:08 ` Andy Lutomirski
2019-04-28 19:43 ` rostedt
2019-04-28 19:43 ` Steven Rostedt
2019-04-28 20:56 ` luto
2019-04-28 20:56 ` Andy Lutomirski
2019-04-28 21:22 ` nstange
2019-04-28 21:22 ` Nicolai Stange
2019-04-28 23:27 ` luto
2019-04-28 23:27 ` Andy Lutomirski
2019-04-27 10:06 ` [PATCH 2/4] ftrace: drop 'static' qualifier from ftrace_ops_list_func() nstange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation nstange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:26 ` peterz
2019-04-27 10:26 ` Peter Zijlstra
2019-04-28 17:38 ` rostedt
2019-04-28 17:38 ` Steven Rostedt
2019-04-29 18:06 ` torvalds
2019-04-29 18:06 ` Linus Torvalds
2019-04-29 18:22 ` torvalds
2019-04-29 18:22 ` Linus Torvalds
2019-04-29 18:42 ` luto
2019-04-29 18:42 ` Andy Lutomirski
[not found] ` <CAHk-=whtt4K2f0KPtG-4Pykh3FK8UBOjD8jhXCUKB5nWDj_YRA@mail.gmail.com>
2019-04-29 18:56 ` luto
2019-04-29 18:56 ` Andy Lutomirski
[not found] ` <CAHk-=wgewK4eFhF3=0RNtk1KQjMANFH6oDE=8m=84RExn2gxhw@mail.gmail.com>
[not found] ` <CAHk-=whay7eN6+2gZjY-ybRbkbcqAmgrLwwszzHx8ws3c=S-MA@mail.gmail.com>
2019-04-29 19:24 ` luto
2019-04-29 19:24 ` Andy Lutomirski
2019-04-29 20:07 ` torvalds
2019-04-29 20:07 ` Linus Torvalds
2019-04-30 13:56 ` peterz [this message]
2019-04-30 13:56 ` Peter Zijlstra
2019-04-30 16:06 ` torvalds
2019-04-30 16:06 ` Linus Torvalds
2019-04-30 16:33 ` luto
2019-04-30 16:33 ` Andy Lutomirski
2019-04-30 17:03 ` rostedt
2019-04-30 17:03 ` Steven Rostedt
2019-04-30 17:20 ` rostedt
2019-04-30 17:20 ` Steven Rostedt
2019-04-30 17:49 ` [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler rostedt
2019-04-30 17:49 ` Steven Rostedt
2019-04-30 18:33 ` torvalds
2019-04-30 18:33 ` Linus Torvalds
2019-04-30 19:00 ` rostedt
2019-04-30 19:00 ` Steven Rostedt
2019-04-30 21:08 ` rostedt
2019-04-30 21:08 ` Steven Rostedt
2019-05-01 13:11 ` peterz
2019-05-01 13:11 ` Peter Zijlstra
2019-05-01 18:58 ` rostedt
2019-05-01 18:58 ` Steven Rostedt
2019-05-01 19:03 ` peterz
2019-05-01 19:03 ` Peter Zijlstra
2019-05-01 19:03 ` torvalds
2019-05-01 19:03 ` Linus Torvalds
2019-05-01 19:13 ` peterz
2019-05-01 19:13 ` Peter Zijlstra
2019-05-01 19:13 ` rostedt
2019-05-01 19:13 ` Steven Rostedt
2019-05-01 19:33 ` jikos
2019-05-01 19:33 ` Jiri Kosina
2019-05-01 19:41 ` peterz
2019-05-01 19:41 ` Peter Zijlstra
2019-04-30 21:53 ` [RFC][PATCH v2] " rostedt
2019-04-30 21:53 ` Steven Rostedt
2019-05-01 1:35 ` rostedt
2019-05-01 1:35 ` Steven Rostedt
2019-05-01 1:58 ` torvalds
2019-05-01 1:58 ` Linus Torvalds
2019-05-01 8:26 ` nstange
2019-05-01 8:26 ` Nicolai Stange
2019-05-01 13:22 ` rostedt
2019-05-01 13:22 ` Steven Rostedt
2019-04-29 20:16 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation torvalds
2019-04-29 20:16 ` Linus Torvalds
2019-04-29 22:08 ` sean.j.christopherson
2019-04-29 22:08 ` Sean Christopherson
2019-04-29 22:22 ` torvalds
2019-04-29 22:22 ` Linus Torvalds
2019-04-30 0:08 ` sean.j.christopherson
2019-04-30 0:08 ` Sean Christopherson
2019-04-30 0:45 ` sean.j.christopherson
2019-04-30 0:45 ` Sean Christopherson
2019-04-30 2:26 ` torvalds
2019-04-30 2:26 ` Linus Torvalds
2019-04-30 10:40 ` peterz
2019-04-30 10:40 ` Peter Zijlstra
2019-04-30 11:17 ` jikos
2019-04-30 11:17 ` Jiri Kosina
2019-04-29 22:06 ` torvalds
2019-04-29 22:06 ` Linus Torvalds
2019-04-30 11:18 ` peterz
2019-04-30 11:18 ` Peter Zijlstra
2019-04-29 18:52 ` rostedt
2019-04-29 18:52 ` Steven Rostedt
[not found] ` <CAHk-=wjm93jLtVxTX4HZs6K4k1Wqh3ujjmapqaYtcibVk_YnzQ@mail.gmail.com>
2019-04-29 19:07 ` rostedt
2019-04-29 19:07 ` Steven Rostedt
2019-04-29 20:06 ` torvalds
2019-04-29 20:06 ` Linus Torvalds
2019-04-29 20:20 ` torvalds
2019-04-29 20:20 ` Linus Torvalds
2019-04-29 20:30 ` rostedt
2019-04-29 20:30 ` Steven Rostedt
2019-04-29 21:38 ` torvalds
2019-04-29 21:38 ` Linus Torvalds
2019-04-29 22:07 ` rostedt
2019-04-29 22:07 ` Steven Rostedt
2019-04-30 9:24 ` nstange
2019-04-30 9:24 ` Nicolai Stange
2019-04-30 10:46 ` peterz
2019-04-30 10:46 ` Peter Zijlstra
2019-04-30 13:44 ` rostedt
2019-04-30 13:44 ` Steven Rostedt
2019-04-30 14:20 ` peterz
2019-04-30 14:20 ` Peter Zijlstra
2019-04-30 14:36 ` rostedt
2019-04-30 14:36 ` Steven Rostedt
2019-04-27 10:06 ` [PATCH 4/4] selftests/livepatch: add "ftrace a live patched function" test nstange
2019-04-27 10:06 ` Nicolai Stange
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=20190430135602.GD2589@hirez.programming.kicks-ass.net \
--to=linux-kselftest@vger.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;
as well as URLs for NNTP newsgroup(s).