Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 19 Aug 2015 08:50:25 -0700 | Subject | Re: [PATCH v2 1/3] x86/entry/64: Refactor IRQ stacks and make them NMI-safe |
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On Mon, Aug 17, 2015 at 4:18 AM, Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Sat, Jul 25, 2015 at 8:57 AM, Andy Lutomirski <luto@kernel.org> wrote: >> This will allow IRQ stacks to nest inside NMIs or similar entries >> that can happen during IRQ stack setup or teardown. >> >> The Xen code here has a confusing comment. >> >> The new macros won't work correctly if they're invoked with IRQs on. >> Add a check under CONFIG_DEBUG_ENTRY to detect that. >> > >> +/* >> + * Enters the IRQ stack if we're not already using it. NMI-safe. Clobbers >> + * flags and puts old RSP into old_rsp, and leaves all other GPRs alone. >> + * Requires kernel GSBASE. >> + * >> + * The invariant is that, if irq_count != 1, then the IRQ stack is in use. >> + */ > > I might be wrong, but shouldn't be this read as 'if irq_count != -1' ? >
Indeed. Will fix for the next version.
--Andy
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