Re: [PATCH V12 05/10] acpi: apei: handle SEA notification type for ARMv8

[Baicar, Tyler]

Hello James,


On 3/7/2017 4:37 AM, James Morse wrote:
> On 06/03/17 20:44, 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().
> > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> > index d178dc0..b2d57fc 100644
> > --- a/arch/arm64/mm/fault.c
> > +++ b/arch/arm64/mm/fault.c
> > @@ -41,6 +41,8 @@
> >   #include <asm/pgtable.h>
> >   #include <asm/tlbflush.h>
> >   
> > +#include <acpi/ghes.h>
> > +
> >   static const char *fault_name(unsigned int esr);
> >   
> >   #ifdef CONFIG_KPROBES
> > @@ -498,6 +500,17 @@ 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",
> >   		 fault_name(esr), 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(ACPI_APEI_SEA)) {
> IS_ENABLED() needs the CONFIG_ version of the symbols, otherwise this doesn't
> get built.
>
> (I guess the testing from the previous always-enabled version is still valid)
Okay, I will use CONFIG_ACPI_APEI_SEA in the next patch set.
> > +		nmi_enter();
> > +		ghes_notify_sea();
> > +		nmi_exit();
> > +	}
> > +
> >   	info.si_signo = SIGBUS;
> >   	info.si_errno = 0;
> >   	info.si_code  = 0;
> > diff --git a/drivers/acpi/apei/Kconfig b/drivers/acpi/apei/Kconfig
> > index b0140c8..c545dd1 100644
> > --- a/drivers/acpi/apei/Kconfig
> > +++ b/drivers/acpi/apei/Kconfig
> > @@ -39,6 +39,21 @@ config ACPI_APEI_PCIEAER
> >   	  PCIe AER errors may be reported via APEI firmware first mode.
> >   	  Turn on this option to enable the corresponding support.
> >   
> > +config ACPI_APEI_SEA
> > +	bool "APEI Synchronous External Abort logging/recovering support"
> > +	depends on ARM64 && ACPI_APEI && ACPI_APEI_GHES
> Nit: ACPI_APEI_GHES already depends on ACPI_APEI
I can remove ACPI_APEI here then.
> > +	default y
> > +	help
> > +	  This option should be enabled if the system supports
> > +	  firmware first handling of SEA (Synchronous External Abort).
> > +	  SEA happens with certain faults of data abort or instruction
> > +	  abort synchronous exceptions on ARMv8 systems. If a system
> > +	  supports firmware first handling of SEA, the platform analyzes
> > +	  and handles hardware error notifications from SEA, and it may then
> > +	  form a HW error record for the OS to parse and handle. This
> > +	  option allows the OS to look for such hardware error record, and
> > +	  take appropriate action.
> > +
> >   config ACPI_APEI_MEMORY_FAILURE
> >   	bool "APEI memory error recovering support"
> >   	depends on ACPI_APEI && MEMORY_FAILURE
>
> Reviewed-by: James Morse <james.morse@xxxxxxx>
Thanks!
Tyler

--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.