ACPI, APEI, Printk queued error record before panic

Because printk is not safe inside NMI handler, the recoverable error
records received in NMI handler will be queued to be printked in a
delayed IRQ context via irq_work.  If a fatal error occurs after the
recoverable error and before the irq_work processed, we lost a error
report.

To solve the issue, the queued error records are printked in NMI
handler if system will go panic.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 44 insertions, 9 deletions

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 9dcb2d86aea..aaf36090de1 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -740,26 +740,34 @@ static int ghes_notify_sci(struct notifier_block *this,
         return ret;
 }
 
+static struct llist_node *llist_nodes_reverse(struct llist_node *llnode)
+{
+        struct llist_node *next, *tail = NULL;
+
+        while (llnode) {
+                next = llnode->next;
+                llnode->next = tail;
+                tail = llnode;
+                llnode = next;
+        }
+
+        return tail;
+}
+
 static void ghes_proc_in_irq(struct irq_work *irq_work)
 {
-        struct llist_node *llnode, *next, *tail = NULL;
+        struct llist_node *llnode, *next;
         struct ghes_estatus_node *estatus_node;
         struct acpi_hest_generic *generic;
         struct acpi_hest_generic_status *estatus;
         u32 len, node_len;
 
+        llnode = llist_del_all(&ghes_estatus_llist);
         /*
          * Because the time order of estatus in list is reversed,
          * revert it back to proper order.
          */
-        llnode = llist_del_all(&ghes_estatus_llist);
-        while (llnode) {
-                next = llnode->next;
-                llnode->next = tail;
-                tail = llnode;
-                llnode = next;
-        }
-        llnode = tail;
+        llnode = llist_nodes_reverse(llnode);
         while (llnode) {
                 next = llnode->next;
                 estatus_node = llist_entry(llnode, struct ghes_estatus_node,
@@ -779,6 +787,32 @@ static void ghes_proc_in_irq(struct irq_work *irq_work)
         }
 }
 
+static void ghes_print_queued_estatus(void)
+{
+        struct llist_node *llnode;
+        struct ghes_estatus_node *estatus_node;
+        struct acpi_hest_generic *generic;
+        struct acpi_hest_generic_status *estatus;
+        u32 len, node_len;
+
+        llnode = llist_del_all(&ghes_estatus_llist);
+        /*
+         * Because the time order of estatus in list is reversed,
+         * revert it back to proper order.
+         */
+        llnode = llist_nodes_reverse(llnode);
+        while (llnode) {
+                estatus_node = llist_entry(llnode, struct ghes_estatus_node,
+                                           llnode);
+                estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
+                len = apei_estatus_len(estatus);
+                node_len = GHES_ESTATUS_NODE_LEN(len);
+                generic = estatus_node->generic;
+                ghes_print_estatus(NULL, generic, estatus);
+                llnode = llnode->next;
+        }
+}
+
 static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
 {
         struct ghes *ghes, *ghes_global = NULL;
@@ -804,6 +838,7 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
 
         if (sev_global >= GHES_SEV_PANIC) {
                 oops_begin();
+                ghes_print_queued_estatus();
                 __ghes_print_estatus(KERN_EMERG, ghes_global->generic,
                                      ghes_global->estatus);
                 /* reboot to log the error! */