[PATCH] ACPI / APEI: restore interrupt before panic in sdei flow

[Liguang Zhang <zhangliguang@linux.alibaba.com>]

We use ACPI_HEST_NOTIFY_SOFTWARE_DELEGATED Notify type for ras event.

In ATF:
ehf_activate_priority()
   dispatch sdei()
ehf_deactivate_priority()

If ras error severity is fatal, panic was called in sdei(),
ehf_deactivate_priority was not called. we should restore interrupt before panic
otherwise kdump will trigger error.

Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
---
 drivers/acpi/apei/ghes.c    | 25 +++++++++++++++++++++----
 drivers/firmware/arm_sdei.c | 14 ++++++++++++++
 include/linux/arm_sdei.h    |  2 ++
 3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 0c8330ed1ffd..4f734c60987c 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -141,6 +141,7 @@ static unsigned long ghes_estatus_pool_size_request;
 static struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
 static atomic_t ghes_estatus_cache_alloced;
 
+static bool ghes_sdei_callback;
 static int ghes_panic_timeout __read_mostly = 30;
 
 static void __iomem *ghes_map(u64 pfn, enum fixed_addresses fixmap_idx)
@@ -837,18 +838,30 @@ static void ghes_estatus_cache_add(
 	rcu_read_unlock();
 }
 
+static void sdei_api_restore_ras(void)
+{
+	/* reboot to log the error! */
+	if (!panic_timeout)
+		panic_timeout = ghes_panic_timeout;
+	panic("Fatal hardware error!");
+}
+
 static void __ghes_panic(struct ghes *ghes,
 			 struct acpi_hest_generic_status *estatus,
 			 u64 buf_paddr, enum fixed_addresses fixmap_idx)
 {
+	int err;
+
 	__ghes_print_estatus(KERN_EMERG, ghes->generic, estatus);
 
 	ghes_clear_estatus(ghes, estatus, buf_paddr, fixmap_idx);
 
-	/* reboot to log the error! */
-	if (!panic_timeout)
-		panic_timeout = ghes_panic_timeout;
-	panic("Fatal hardware error!");
+	if (ghes_sdei_callback) {
+		err = sdei_api_event_complete_and_resume((unsigned long)sdei_api_restore_ras);
+		if (err)
+			sdei_api_restore_ras();
+	} else
+		sdei_api_restore_ras();
 }
 
 static int ghes_proc(struct ghes *ghes)
@@ -1224,7 +1237,9 @@ static int ghes_sdei_normal_callback(u32 event_num, struct pt_regs *regs,
 	int err;
 
 	raw_spin_lock(&ghes_notify_lock_sdei_normal);
+	ghes_sdei_callback = true;
 	err = __ghes_sdei_callback(ghes, FIX_APEI_GHES_SDEI_NORMAL);
+	ghes_sdei_callback = false;
 	raw_spin_unlock(&ghes_notify_lock_sdei_normal);
 
 	return err;
@@ -1238,7 +1253,9 @@ static int ghes_sdei_critical_callback(u32 event_num, struct pt_regs *regs,
 	int err;
 
 	raw_spin_lock(&ghes_notify_lock_sdei_critical);
+	ghes_sdei_callback = true;
 	err = __ghes_sdei_callback(ghes, FIX_APEI_GHES_SDEI_CRITICAL);
+	ghes_sdei_callback = false;
 	raw_spin_unlock(&ghes_notify_lock_sdei_critical);
 
 	return err;
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index a7e762c352f9..1af6b6b55c57 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -473,6 +473,20 @@ static int sdei_api_event_unregister(u32 event_num)
 			      0, 0, 0, NULL);
 }
 
+int sdei_api_event_complete_and_resume(u64 addr)
+{
+	int err;
+
+	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME, addr,
+			      0, 0, 0, 0, NULL);
+	if (err && err != -EIO) {
+		pr_warn_once("failed to restore CPU[%u]: %d\n", smp_processor_id(), err);
+		return err;
+	}
+
+	return 0;
+}
+
 /* Called directly by the hotplug callbacks */
 static void _local_event_unregister(void *data)
 {
diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
index 0a241c5c911d..b6d347085834 100644
--- a/include/linux/arm_sdei.h
+++ b/include/linux/arm_sdei.h
@@ -46,9 +46,11 @@ int sdei_unregister_ghes(struct ghes *ghes);
 /* For use by arch code when CPU hotplug notifiers are not appropriate. */
 int sdei_mask_local_cpu(void);
 int sdei_unmask_local_cpu(void);
+int sdei_api_event_complete_and_resume(u64 addr);
 #else
 static inline int sdei_mask_local_cpu(void) { return 0; }
 static inline int sdei_unmask_local_cpu(void) { return 0; }
+int sdei_api_event_complete_and_resume(u64 addr) { return 0; }
 #endif /* CONFIG_ARM_SDE_INTERFACE */
 
 
-- 
2.19.1.6.gb485710b