Re: [tip:x86/asm] x86/asm/entry/64: Rename 'old_rsp' to 'rsp_scratch'

From: Ingo Molnar
Date: Mon Mar 23 2015 - 09:58:44 EST



* Denys Vlasenko <dvlasenk@xxxxxxxxxx> wrote:

> On 03/17/2015 05:43 PM, tip-bot for Ingo Molnar wrote:
> > Commit-ID: c38e503804b0402c510f82437069f7769fa0cea9
> > Gitweb: http://git.kernel.org/tip/c38e503804b0402c510f82437069f7769fa0cea9
> > Author: Ingo Molnar <mingo@xxxxxxxxxx>
> > AuthorDate: Tue, 17 Mar 2015 14:42:59 +0100
> > Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> > CommitDate: Tue, 17 Mar 2015 16:01:42 +0100
> >
> > x86/asm/entry/64: Rename 'old_rsp' to 'rsp_scratch'
> >
> > Make clear that the usage of PER_CPU(old_rsp) is purely temporary,
> > by renaming it to 'rsp_scratch'.
> ...
> > @@ -657,7 +657,7 @@ common_interrupt:
> > ASM_CLAC
> > addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */
> > interrupt do_IRQ
> > - /* 0(%rsp): old_rsp */
> > + /* 0(%rsp): rsp_scratch */
> > ret_from_intr:
>
> Here the "old_rsp" word in comment did not refer to old_rsp variable.
>
> Rather, it literally means "old %rsp register value (before we possibly
> switched to per-CPU interrupt stack)".
>
> The stack switch is hidden in "interrupt do_IRQ" macro invocation.
>
> I think here "old_rsp" needs to be replaced by "old rsp" or "old %rsp".

Indeed - and I applied your comment-fix patch.

Thanks,

Ingo
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