[PATCH V1 6/6] acpi: apei: handle SEA notification type for ARMv8

ARM APEI extension proposal added SEA (Synchrounous 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.

Signed-off-by: Jonathan (Zhixiong) Zhang <redacted>
Signed-off-by: Tyler Baicar <redacted>
Signed-off-by: Naveen Kaje <redacted>
---
 arch/arm64/Kconfig        |  1 +
 drivers/acpi/apei/Kconfig | 13 ++++++++
 drivers/acpi/apei/ghes.c  | 83 +++++++++++++++++++++++++++++++++++++++++++++++
 include/acpi/actbl1.h     |  6 +++-
 4 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6e4a4f4..236f398 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -6,6 +6,7 @@ config ARM64
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select HAVE_ACPI_APEI if ACPI
+	select HAVE_ACPI_APEI_SEA if ACPI
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_GCOV_PROFILE_ALL

diff --git a/drivers/acpi/apei/Kconfig b/drivers/acpi/apei/Kconfig
index a60bb00..bfcbb9e 100644
--- a/drivers/acpi/apei/Kconfig
+++ b/drivers/acpi/apei/Kconfig

@@ -7,6 +7,19 @@ config HAVE_ACPI_APEI_NMI
 config HAVE_ACPI_APEI_HEST_IA32
 	bool
 
+config HAVE_ACPI_APEI_SEA
+	bool "APEI Synchronous External Abort logging/recovering support"
+	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 with 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 HW error record, and
+	  take appropriate action.
+
 config ACPI_APEI
 	bool "ACPI Platform Error Interface (APEI)"
 	select MISC_FILESYSTEMS

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 6c68100..ed64b97 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c

@@ -50,6 +50,10 @@
 #include <acpi/apei.h>
 #include <asm/tlbflush.h>
 
+#ifdef CONFIG_HAVE_ACPI_APEI_SEA
+#include <asm/system_misc.h>
+#endif
+
 #include "apei-internal.h"
 
 #define GHES_PFX	"GHES: "

@@ -784,6 +788,62 @@ static struct notifier_block ghes_notifier_sci = {
 	.notifier_call = ghes_notify_sci,
 };
 
+#ifdef CONFIG_HAVE_ACPI_APEI_SEA
+static LIST_HEAD(ghes_sea);
+
+static int ghes_notify_sea(struct notifier_block *this,
+				  unsigned long event, void *data)
+{
+	struct ghes *ghes;
+	int ret = NOTIFY_DONE;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ghes, &ghes_sea, list) {
+		if (!ghes_proc(ghes))
+			ret = NOTIFY_OK;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static struct notifier_block ghes_notifier_sea = {
+	.notifier_call = ghes_notify_sea,
+};
+
+static int ghes_sea_add(struct ghes *ghes)
+{
+	mutex_lock(&ghes_list_mutex);