Re: [PATCH V15 06/11] acpi: apei: handle SEA notification type for ARMv8

[Baicar, Tyler]

On 4/25/2017 11:21 AM, Borislav Petkov wrote:
> On Tue, Apr 18, 2017 at 05:05:18PM -0600, Tyler Baicar wrote:
> > ARM APEI extension proposal added SEA (Synchronous External Abort)
> > notification type for ARMv8.
> > Add a new GHES error source handling function for SEA. If an error
> > source's notification type is SEA, then this function can be registered
> > into the SEA exception handler. That way GHES will parse and report
> > SEA exceptions when they occur.
> > An SEA can interrupt code that had interrupts masked and is treated as
> > an NMI. To aid this the page of address space for mapping APEI buffers
> > while in_nmi() is always reserved, and ghes_ioremap_pfn_nmi() is
> > changed to use the helper methods to find the prot_t to map with in
> > the same way as ghes_ioremap_pfn_irq().
> ...
>
> > @@ -518,6 +520,17 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
> >   	pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
> >   		inf->name, esr, addr);
> >   
> > +	/*
> > +	 * Synchronous aborts may interrupt code which had interrupts masked.
> > +	 * Before calling out into the wider kernel tell the interested
> > +	 * subsystems.
> > +	 */
> > +	if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) {
> > +		nmi_enter();
> > +		ghes_notify_sea();
> > +		nmi_exit();
> > +	}
> Well, the other GHES notification methods use a notifier:
> ghes_notify_sci, ghes_notify_nmi. You probably should do that too
> instead of calling straight into a driver from arch code.
I originally had this as a notifier, but Will requested to remove the 
notifier. That conversation is here: https://lkml.org/lkml/2017/1/18/1018

Thanks,
Tyler

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