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* [PATCH AUTOSEL 4.4 049/100] ACPICA: Disassembler: create buffer fields in ACPI_PARSE_LOAD_PASS1
       [not found] <20200214162425.21071-1-sashal@kernel.org>
@ 2020-02-14 16:23 ` Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2020-02-14 16:23 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Erik Kaneda, Elia Geretto, Bob Moore, Rafael J . Wysocki,
	Sasha Levin, linux-acpi, devel

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 20de148594fdc..d56cbcda37c13 100644
--- a/drivers/acpi/acpica/dsfield.c
+++ b/drivers/acpi/acpica/dsfield.c
@@ -272,7 +272,7 @@ acpi_ds_create_buffer_field(union acpi_parse_object *op,
  * 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 097188a6b1c1b..35f1d7657927a 100644
--- a/drivers/acpi/acpica/dswload.c
+++ b/drivers/acpi/acpica/dswload.c
@@ -440,6 +440,27 @@ 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


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