[kvm-unit-tests PATCH v5 07/29] lib/acpi: Ensure all struct definition for ACPI tables are packed

[Nikos Nikoleris <nikos.nikoleris@arm.com>]

All ACPI table definitions are provided with precise definitions of
field sizes and offsets, make sure that no compiler optimization can
interfere with the memory layout of the corresponding structs.

Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
---
 lib/acpi.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/acpi.h b/lib/acpi.h
index f9a344e9..53e41c4b 100644
--- a/lib/acpi.h
+++ b/lib/acpi.h
@@ -3,6 +3,12 @@
 
 #include "libcflat.h"
 
+/*
+ * All tables and structures must be byte-packed to match the ACPI
+ * specification, since the tables are provided by the system firmware.
+ */
+#pragma pack(1)
+
 #define ACPI_SIGNATURE(c1, c2, c3, c4) \
 	((c1) | ((c2) << 8) | ((c3) << 16) | ((c4) << 24))
 
@@ -103,6 +109,8 @@ struct acpi_table_facs_rev1 {
 	u8 reserved3[40];	/* Reserved - must be zero */
 };
 
+#pragma pack(0)
+
 void set_efi_rsdp(struct acpi_table_rsdp *rsdp);
 void *find_acpi_table_addr(u32 sig);
 
-- 
2.25.1