ACPI has a GHESv2 which is used on hardware reduced platforms to
explicitly acknowledge that the memory for CPER records has been
consumed. This lets an external agent know it can re-use this
memory for something else.

Previously notify_nmi and the estatus queue didn't do this as
they were never used on hardware reduced platforms. Once we move
notify_sea over to use the estatus queue, it may become necessary.

Add the call. This is safe for use in NMI context as the
read_ack_register is pre-mapped by ghes_new() before the
ghes can be added to an RCU list, and then found by the
notification handler.

Signed-off-by: James Morse <james.morse@arm.com>
---
 drivers/acpi/apei/ghes.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 366dbdd41ef3..15d94373ba72 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c

@@ -926,6 +926,10 @@ static int _in_nmi_notify_one(struct ghes *ghes)
 	__process_error(ghes);
 	ghes_clear_estatus(ghes, buf_paddr);
 
+	if (is_hest_type_generic_v2(ghes) && ghes_ack_error(ghes->generic_v2))
+		pr_warn_ratelimited(FW_WARN GHES_PFX
+				    "Failed to ack error status block!\n");
+
 	return 0;
 }
 

-- 
2.19.2


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