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-rw-r--r--src/include/boot/linuxbios_tables.h38
1 files changed, 34 insertions, 4 deletions
diff --git a/src/include/boot/linuxbios_tables.h b/src/include/boot/linuxbios_tables.h
index 9288d3b23c..527c44d5fc 100644
--- a/src/include/boot/linuxbios_tables.h
+++ b/src/include/boot/linuxbios_tables.h
@@ -31,6 +31,40 @@
* table entries and be backwards compatible, but it is not required.
*/
+/* Since LinuxBIOS is usually compiled 32bit, gcc will align 64bit
+ * types to 32bit boundaries. If the LinuxBIOS table is dumped on a
+ * 64bit system, a uint64_t would be aligned to 64bit boundaries,
+ * breaking the table format.
+ *
+ * lb_uint64 will keep 64bit LinuxBIOS table values aligned to 32bit
+ * to ensure compatibility. They can be accessed with the two functions
+ * below: unpack_lb64() and pack_lb64()
+ *
+ * See also: util/lbtdump/lbtdump.c
+ */
+
+struct lb_uint64 {
+ uint32_t lo;
+ uint32_t hi;
+};
+
+static inline uint64_t unpack_lb64(struct lb_uint64 value)
+{
+ uint64_t result;
+ result = value.hi;
+ result = (result << 32) + value.lo;
+ return result;
+}
+
+static inline struct lb_uint64 pack_lb64(uint64_t value)
+{
+ struct lb_uint64 result;
+ result.lo = (value >> 0) & 0xffffffff;
+ result.hi = (value >> 32) & 0xffffffff;
+ return result;
+}
+
+
struct lb_header
{
@@ -57,10 +91,6 @@ struct lb_record {
#define LB_TAG_MEMORY 0x0001
-struct lb_uint64 {
- uint32_t lo;
- uint32_t hi;
-};
struct lb_memory_range {
struct lb_uint64 start;
struct lb_uint64 size;