Messages in this thread | | | Subject | Re: [PATCH 5/6] x86: Remove useless unwinder backlink from irq regs saving | From | Valdis.Kletnieks@vt ... | Date | Tue, 05 Jul 2011 18:21:28 -0400 |
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On Mon, 04 Jul 2011 15:22:23 +0200, Frederic Weisbecker said: > On Mon, Jul 04, 2011 at 08:29:08AM +0100, Jan Beulich wrote: > > >>> On 02.07.11 at 18:29, Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > The unwinder backlink in interrupt entry is very useless. > > > It's actually not part of the stack frame chain and thus is > > > never used. > > > > I very much doubt this - see dump_trace()'s comment in its IRQ-stack > > related code portion (and the corresponding use of irq_stack_end[-1]). > > > > Jan > > Good point. I misunderstood that. > > But then I believe I accidentally fixed it back in > "x86: Don't use frame pointer to save old stack on irq entry" by > pushing %rsi instead in the new stack. It contains the backlink to > the old stack. > > If we keep the macro as-is, I'll add a comment to explain further > what is involved there.
Ahh.. I was wondering why there wasn't suddenly a very lonely popq out there... :) [unhandled content-type:application/pgp-signature] | |