ACPICA: Headers: Deploy #pragma pack (push) and (pop).

Use push and pop to both guarantee that the correct alignment is used,
and to restore the alignment to whatever it was before the header
was included.

It is reported that the #pragma pack(push/pop) directives are not supported
by the specific GCCs, but this patch still doesn't affect kernel build
as there are already #pragma pack([1]) directives used in the old ACPICA
headers, which means there shouldn't be GCCs that are currently used to
compile the ACPI kernels do not support #pragma pack() directives.

References: https://bugs.acpica.org/show_bug.cgi?id=1058
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/amlcode.h b/drivers/acpi/acpica/amlcode.h
index 5908ccec6aea..2db27109d70e 100644
--- a/drivers/acpi/acpica/amlcode.h
+++ b/drivers/acpi/acpica/amlcode.h
@@ -46,6 +46,8 @@
 #ifndef __AMLCODE_H__
 #define __AMLCODE_H__
 
+#pragma pack(push)              /* Set default struct packing */
+
 /* primary opcodes */
 
 #define AML_NULL_CHAR               (u16) 0x00
@@ -484,4 +486,6 @@ typedef enum {
 #define AML_METHOD_SERIALIZED       0x08
 #define AML_METHOD_SYNC_LEVEL       0xF0
 
+#pragma pack(pop)               /* Restore original struct packing */
+
 #endif                          /* __AMLCODE_H__ */