[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <alpine.DEB.2.21.1807192250360.1693@nanos.tec.linutronix.de>
Date: Thu, 19 Jul 2018 22:52:04 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: Brian Gerst <brgerst@...il.com>
cc: Joerg Roedel <joro@...tes.org>, Ingo Molnar <mingo@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
the arch/x86 maintainers <x86@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux-MM <linux-mm@...ck.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...el.com>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Juergen Gross <jgross@...e.com>,
Peter Zijlstra <peterz@...radead.org>,
Borislav Petkov <bp@...en8.de>, Jiri Kosina <jkosina@...e.cz>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
David Laight <David.Laight@...lab.com>,
Denys Vlasenko <dvlasenk@...hat.com>,
Eduardo Valentin <eduval@...zon.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Will Deacon <will.deacon@....com>,
"Liguori, Anthony" <aliguori@...zon.com>,
Daniel Gruss <daniel.gruss@...k.tugraz.at>,
Hugh Dickins <hughd@...gle.com>,
Kees Cook <keescook@...gle.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Waiman Long <llong@...hat.com>, Pavel Machek <pavel@....cz>,
dhgutteridge@...patico.ca, Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH 07/39] x86/entry/32: Enter the kernel via trampoline
stack
On Wed, 18 Jul 2018, Brian Gerst wrote:
> > +.Lcopy_pt_regs_\@:
> > +#endif
> > +
> > + /* Allocate frame on task-stack */
> > + subl %ecx, %edi
> > +
> > + /* Switch to task-stack */
> > + movl %edi, %esp
> > +
> > + /*
> > + * We are now on the task-stack and can safely copy over the
> > + * stack-frame
> > + */
> > + shrl $2, %ecx
>
> This shift can be removed if you divide the constants by 4 above.
> Ditto on the exit path in the next patch.
No, the
> > + /* Allocate frame on task-stack */
> > + subl %ecx, %edi
needs the full value in bytes ....
Thanks,
tglx
Powered by blists - more mailing lists