[PATCH v2 7/8] ACPICA: AML Parser: ignore dispatcher error status during table load

[Aaron Ma]

From: "Schmauss, Erik" <erik.schmauss at intel.com>

BugLink: https://bugs.launchpad.net/bugs/1820153

The dispatcher and the executer process the parse nodes During table
load. Error status from the evaluation confuses the AML parser. This
results in the parser failing to complete parsing of the current
scope op which becomes problematic. For the incorrect AML below, _ADR
never gets created.

definition_block(...)
{
   Scope (\_SB)
   {
     Device (PCI0){...}
     Name (OBJ1, 0x0)
     OBJ1 = PCI0 + 5 // Results in an operand error.
   } // \_SB not closed

   // parser looks for \_SB._SB.PCI0, results in AE_NOT_FOUND error
   // Entire scope block gets skipped.
   Scope (\_SB.PCI0)
   {
       Name (_ADR, 0x0)
   }
}

Fix the above error by properly completing the initial \_SB scope
after an error by clearing errors that occur during table load. In
the above case, this means that OBJ1 = PIC0 + 5 is skipped.

Fixes: 5088814a6e93 (ACPICA: AML parser: attempt to continue loading table after error)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200363
Tested-by: Bastien Nocera <hadess at hadess.net>
Signed-off-by: Erik Schmauss <erik.schmauss at intel.com>
Cc: 4.17+ <stable at vger.kernel.org> # 4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
(cherry picked from commit 73c2a01c52b657f4a0ead6c95f64c5279efbd000)
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/acpi/acpica/psloop.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/acpi/acpica/psloop.c b/drivers/acpi/acpica/psloop.c
index f437c3d54086..a5f35ff54510 100644
--- a/drivers/acpi/acpica/psloop.c
+++ b/drivers/acpi/acpica/psloop.c
@@ -513,6 +513,18 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
 			status =
 			    acpi_ps_create_op(walk_state, aml_op_start, &op);
 			if (ACPI_FAILURE(status)) {
+				/*
+				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
+				 * executing it as a control method. However, if we encounter
+				 * an error while loading the table, we need to keep trying to
+				 * load the table rather than aborting the table load. Set the
+				 * status to AE_OK to proceed with the table load.
+				 */
+				if ((walk_state->
+				     parse_flags & ACPI_PARSE_MODULE_LEVEL)
+				    && status == AE_ALREADY_EXISTS) {
+					status = AE_OK;
+				}
 				if (status == AE_CTRL_PARSE_CONTINUE) {
 					continue;
 				}
@@ -710,6 +722,20 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
 			    acpi_ps_next_parse_state(walk_state, op, status);
 			if (status == AE_CTRL_PENDING) {
 				status = AE_OK;
+			} else
+			    if ((walk_state->
+				 parse_flags & ACPI_PARSE_MODULE_LEVEL)
+				&& ACPI_FAILURE(status)) {
+				/*
+				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
+				 * executing it as a control method. However, if we encounter
+				 * an error while loading the table, we need to keep trying to
+				 * load the table rather than aborting the table load. Set the
+				 * status to AE_OK to proceed with the table load. If we get a
+				 * failure at this point, it means that the dispatcher got an
+				 * error while processing Op (most likely an AML operand error.
+				 */
+				status = AE_OK;
 			}
 		}
 
-- 
2.17.1