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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