Messages in this thread | | | Date | Mon, 04 Jul 2011 08:29:08 +0100 | From | "Jan Beulich" <> | Subject | Re: [PATCH 5/6] x86: Remove useless unwinder backlink from irq regs saving |
| |
>>> 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
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: H. Peter Anvin <hpa@zytor.com> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Jan Beulich <JBeulich@novell.com> > --- > arch/x86/kernel/entry_64.S | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S > index 20dc8e6..6131432 100644 > --- a/arch/x86/kernel/entry_64.S > +++ b/arch/x86/kernel/entry_64.S > @@ -327,7 +327,6 @@ ENDPROC(native_usergs_sysret64) > jne 2f > mov PER_CPU_VAR(irq_stack_ptr),%rsp > EMPTY_FRAME 0 > - pushq_cfi %rbp /* backlink for unwinder */ > /* > * We entered an interrupt context - irqs are off: > */
| |