x86_64: Align uint64_t/int64_t structure member to 8 bytes
To make sure the stature which pass between 32/64bit process have
same memory layout for 32/64bit.
Signed-off-by: Fengwei Yin <fengwei.yin@intel.com>
Co-Authored-by: Narayan Kamath <narayan@google.com> (Unit test only.)
Change-Id: I1bc2d12cce41ec0bc484adcaf968f274bec75c12
diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index 8ffdfca..e7e383b 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -39,6 +39,9 @@
/*
* Intermediate representation used to send input events and related signals.
+ *
+ * Note that this structure is used for IPCs so its layout must be identical
+ * on 64 and 32 bit processes. This is tested in StructLayout_test.cpp.
*/
struct InputMessage {
enum {
@@ -49,13 +52,17 @@
struct Header {
uint32_t type;
- uint32_t padding; // 8 byte alignment for the body that follows
+ // We don't need this field in order to align the body below but we
+ // leave it here because InputMessage::size() and other functions
+ // compute the size of this structure as sizeof(Header) + sizeof(Body).
+ uint32_t padding;
} header;
+ // Body *must* be 8 byte aligned.
union Body {
struct Key {
uint32_t seq;
- nsecs_t eventTime;
+ nsecs_t eventTime __attribute__((aligned(8)));
int32_t deviceId;
int32_t source;
int32_t action;
@@ -64,7 +71,7 @@
int32_t scanCode;
int32_t metaState;
int32_t repeatCount;
- nsecs_t downTime;
+ nsecs_t downTime __attribute__((aligned(8)));
inline size_t size() const {
return sizeof(Key);
@@ -73,7 +80,7 @@
struct Motion {
uint32_t seq;
- nsecs_t eventTime;
+ nsecs_t eventTime __attribute__((aligned(8)));
int32_t deviceId;
int32_t source;
int32_t action;
@@ -81,13 +88,14 @@
int32_t metaState;
int32_t buttonState;
int32_t edgeFlags;
- nsecs_t downTime;
+ nsecs_t downTime __attribute__((aligned(8)));
float xOffset;
float yOffset;
float xPrecision;
float yPrecision;
uint32_t pointerCount;
- struct Pointer {
+ // Note that PointerCoords requires 8 byte alignment.
+ struct Pointer{
PointerProperties properties;
PointerCoords coords;
} pointers[MAX_POINTERS];
@@ -112,7 +120,7 @@
return sizeof(Finished);
}
} finished;
- } body;
+ } __attribute__((aligned(8))) body;
bool isValid(size_t actualSize) const;
size_t size() const;