[PATCH 4.14 087/237] ACPICA: Disassembler: create buffer fields in ACPI_PARSE_LOAD_PASS1

Greg Kroah-Hartman
2020-02-27T14:38:49Z

From: Erik Kaneda <erik.kaneda@intel.com>

[ Upstream commit 5ddbd77181dfca61b16d2e2222382ea65637f1b9 ]

ACPICA commit 29cc8dbc5463a93625bed87d7550a8bed8913bf4

create_buffer_field is a deferred op that is typically processed in
load pass 2. However, disassembly of control method contents walk the
parse tree with ACPI_PARSE_LOAD_PASS1 and AML_CREATE operators are
processed in a later walk. This is a problem when there is a control
method that has the same name as the AML_CREATE object. In this case,
any use of the name segment will be detected as a method call rather
than a reference to a buffer field. If this is detected as a method
call, it can result in a mal-formed parse tree if the control methods
have parameters.

This change in processing AML_CREATE ops earlier solves this issue by
inserting the named object in the ACPI namespace so that references
to this name would be detected as a name string rather than a method
call.

Link: https://github.com/acpica/acpica/commit/29cc8dbc
Reported-by: Elia Geretto <elia.f.geretto@gmail.com>
Tested-by: Elia Geretto <elia.f.geretto@gmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/acpica/dsfield.c | 2 +-
drivers/acpi/acpica/dswload.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpica/dsfield.c b/drivers/acpi/acpica/dsfield.c
index 7bcf5f5ea0297..8df4a49a99a6b 100644
--- a/drivers/acpi/acpica/dsfield.c
+++ b/drivers/acpi/acpica/dsfield.c
@@ -273,7 +273,7 @@ cleanup:
* FUNCTION: acpi_ds_get_field_names
*
* PARAMETERS: info - create_field info structure
- * ` walk_state - Current method state
+ * walk_state - Current method state
* arg - First parser arg for the field name list
*
* RETURN: Status
diff --git a/drivers/acpi/acpica/dswload.c b/drivers/acpi/acpica/dswload.c
index eaa859a89702a..1d82e1419397e 100644
--- a/drivers/acpi/acpica/dswload.c
+++ b/drivers/acpi/acpica/dswload.c
@@ -444,6 +444,27 @@ acpi_status acpi_ds_load1_end_op(struct acpi_walk_state *walk_state)
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p State=%p\n", op,
walk_state));

+ /*
+ * Disassembler: handle create field operators here.
+ *
+ * create_buffer_field is a deferred op that is typically processed in load
+ * pass 2. However, disassembly of control method contents walk the parse
+ * tree with ACPI_PARSE_LOAD_PASS1 and AML_CREATE operators are processed
+ * in a later walk. This is a problem when there is a control method that
+ * has the same name as the AML_CREATE object. In this case, any use of the
+ * name segment will be detected as a method call rather than a reference
+ * to a buffer field.
+ *
+ * This earlier creation during disassembly solves this issue by inserting
+ * the named object in the ACPI namespace so that references to this name
+ * would be a name string rather than a method call.
+ */
+ if ((walk_state->parse_flags & ACPI_PARSE_DISASSEMBLE) &&
+ (walk_state->op_info->flags & AML_CREATE)) {
+ status = acpi_ds_create_buffer_field(op, walk_state);
+ return_ACPI_STATUS(status);
+ }
+
/* We are only interested in opcodes that have an associated name */

if (!(walk_state->op_info->flags & (AML_NAMED | AML_FIELD))) {
--
2.20.1