From: "H. Peter Anvin" <h.peter.anvin@intel.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Gleb Natapov <gleb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC/HACK] x86: Fast return to kernel
Date: Fri, 02 May 2014 14:44:33 -0700 [thread overview]
Message-ID: <536411C1.4040209@intel.com> (raw)
In-Reply-To: <CALCETrXP7-mtpVhFmM0Cw0pxHs3JpU8uYNJzxi1Qx6=QXW_Vrg@mail.gmail.com>
On 05/02/2014 02:42 PM, Andy Lutomirski wrote:
>
> Hah -- I think I just faked both of you out :)
>
> I don't think this has anything to do with the error code, and I think
> that the errorentry code already does more or less that: it pushes -1.
>
> The real issue here is probably the magic 16-byte stack alignment when
> a non-stack-switching interrupt happens.
>
Errorentry is when there *is* an error code pushed by the hardware. The
other variant is zeroentry, which does generate a zero error code --
eventually. The -1 means we didn't enter the kernel through a system call.
-hpa
next prev parent reply other threads:[~2014-05-02 21:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-02 19:04 [RFC/HACK] x86: Fast return to kernel Andy Lutomirski
2014-05-02 19:31 ` Linus Torvalds
2014-05-02 19:50 ` Andy Lutomirski
2014-05-04 18:40 ` Ingo Molnar
2014-05-04 19:59 ` H. Peter Anvin
2014-05-04 21:31 ` Linus Torvalds
2014-05-04 22:01 ` H. Peter Anvin
2014-05-02 19:51 ` Linus Torvalds
2014-05-02 20:07 ` H. Peter Anvin
2014-05-02 20:30 ` Thomas Gleixner
2014-05-02 21:01 ` Linus Torvalds
2014-05-02 21:04 ` Andy Lutomirski
2014-05-02 21:07 ` Linus Torvalds
2014-05-02 21:37 ` H. Peter Anvin
2014-05-02 21:42 ` Andy Lutomirski
2014-05-02 21:44 ` H. Peter Anvin [this message]
2014-05-02 21:28 ` Thomas Gleixner
2014-05-04 23:46 ` Paolo Bonzini
2014-05-04 23:49 ` H. Peter Anvin
2014-05-02 20:19 ` Steven Rostedt
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