ACPICA: Add a mechanism to escape infinite AML While() loops
Add a loop counter to force exit from AML While loops if the
count becomes too large. This can occur in poorly written AML
when the hardware does not respond within a while loop and the
loop does not implement a timeout. The maximum loop count is
configurable. A new exception code is returned when a loop is
broken, AE_AML_INFINITE_LOOP. Bob Moore, Alexey Starikovskiy.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/acpi/acconfig.h b/include/acpi/acconfig.h
index 29feee2..e50fe71 100644
--- a/include/acpi/acconfig.h
+++ b/include/acpi/acconfig.h
@@ -119,6 +119,10 @@
#define ACPI_ROOT_TABLE_SIZE_INCREMENT 4
+/* Maximum number of While() loop iterations before forced abort */
+
+#define ACPI_MAX_LOOP_ITERATIONS 0xFFFF
+
/******************************************************************************
*
* ACPI Specification constants (Do not change unless the specification changes)
diff --git a/include/acpi/acexcep.h b/include/acpi/acexcep.h
index 84f5cb2..a1ae105 100644
--- a/include/acpi/acexcep.h
+++ b/include/acpi/acexcep.h
@@ -153,8 +153,9 @@
#define AE_AML_CIRCULAR_REFERENCE (acpi_status) (0x001E | AE_CODE_AML)
#define AE_AML_BAD_RESOURCE_LENGTH (acpi_status) (0x001F | AE_CODE_AML)
#define AE_AML_ILLEGAL_ADDRESS (acpi_status) (0x0020 | AE_CODE_AML)
+#define AE_AML_INFINITE_LOOP (acpi_status) (0x0021 | AE_CODE_AML)
-#define AE_CODE_AML_MAX 0x0020
+#define AE_CODE_AML_MAX 0x0021
/*
* Internal exceptions used for control
@@ -267,6 +268,7 @@
"AE_AML_CIRCULAR_REFERENCE",
"AE_AML_BAD_RESOURCE_LENGTH",
"AE_AML_ILLEGAL_ADDRESS",
+ "AE_AML_INFINITE_LOOP"
};
char const *acpi_gbl_exception_names_ctrl[] = {
diff --git a/include/acpi/aclocal.h b/include/acpi/aclocal.h
index ecab527..0323fa9 100644
--- a/include/acpi/aclocal.h
+++ b/include/acpi/aclocal.h
@@ -566,6 +566,7 @@
union acpi_parse_object *predicate_op;
u8 *aml_predicate_start; /* Start of if/while predicate */
u8 *package_end; /* End of if/while block */
+ u32 loop_count; /* While() loop counter */
};
/*
