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ACPICA: AML Parser: fix parse loop to correctly skip erroneous extended opcodes

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AML opcodes come in two lengths: 1-byte opcodes and 2-byte, extended opcodes.
If an error occurs due to illegal opcodes during table load, the AML parser
needs to continue loading the table. In order to do this, it needs to skip
parsing of the offending opcode and operands associated with that opcode.

This change fixes the AML parse loop to correctly skip parsing of incorrect
extended opcodes. Previously, only the short opcodes were skipped correctly.

Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Erik Schmauss 2018-10-17 14:20:51 -07:00 • committed by Rafael J. Wysocki
parent 4abb951b73
commit c64baa3a6f
1 changed files with 13 additions and 1 deletions
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14
drivers/acpi/acpica/psloop.c
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@ -417,6 +417,7 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
union acpi_parse_object *op = NULL; /* current op */
struct acpi_parse_state *parser_state;
u8 *aml_op_start = NULL;
u8 opcode_length;
ACPI_FUNCTION_TRACE_PTR(ps_parse_loop, walk_state);
@ -540,8 +541,19 @@ acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
"Skip parsing opcode %s",
acpi_ps_get_opcode_name
(walk_state->opcode)));
/*
* Determine the opcode length before skipping the opcode.
* An opcode can be 1 byte or 2 bytes in length.
*/
opcode_length = 1;
if ((walk_state->opcode & 0xFF00) ==
AML_EXTENDED_OPCODE) {
opcode_length = 2;
}
walk_state->parser_state.aml =
walk_state->aml + 1;
walk_state->aml + opcode_length;
walk_state->parser_state.aml =
acpi_ps_get_next_package_end
(&walk_state->parser_state);