git: 96acaa960023 - main - compat32: provide a type and a macro for (u)int64_t handling on non-x86 arches

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=96acaa960023c20e852e04e7cc5c6a5faca36c67

commit 96acaa960023c20e852e04e7cc5c6a5faca36c67
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2026-01-12 04:45:36 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2026-01-20 14:42:35 +0000

    compat32: provide a type and a macro for (u)int64_t handling on non-x86 arches
    
    uint64_t is 4-byte aligned on i386, but is 8-bytes aligned on all other
    32bit arches FreeBSD supports.  Provide the freebsd32_uint64_t type and
    the FU64_CP() macro, which are intended to be used where 32bit ABI uses
    (u)int64_t type, and do proper layout and copying for the aggregate type.
    
    Reviewed by:    des, emaste
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D54663
---
 sys/compat/freebsd32/freebsd32.h | 11 ++++++++++-
 sys/sys/abi_compat.h             |  8 ++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/sys/compat/freebsd32/freebsd32.h b/sys/compat/freebsd32/freebsd32.h
index 9d724c93fee7..7324f9adf70c 100644
--- a/sys/compat/freebsd32/freebsd32.h
+++ b/sys/compat/freebsd32/freebsd32.h
@@ -36,8 +36,17 @@
 #include <sys/_ffcounter.h>
 
 /*
- * i386 is the only arch with a 32-bit time_t
+ * i386 is the only arch with a 32-bit time_t.
+ * Also it is the only arch with (u)int64_t having 4-bytes alignment.
  */
+typedef struct {
+#ifdef __amd64__
+	uint32_t val[2];
+#else
+	uint64_t val;
+#endif
+} freebsd32_uint64_t;
+
 #ifdef __amd64__
 typedef	int32_t	time32_t;
 #else
diff --git a/sys/sys/abi_compat.h b/sys/sys/abi_compat.h
index c2233f2eac2c..0a7110191430 100644
--- a/sys/sys/abi_compat.h
+++ b/sys/sys/abi_compat.h
@@ -67,6 +67,14 @@
 	TS_CP((src), (dst), it_value);		\
 } while (0)
 
+#define	FU64_CP(src, dst, fld) do {				\
+	_Static_assert(sizeof((src).fld) == sizeof(uint64_t),	\
+	    "FU64_CP src: " #src "." #fld "is not 8 bytes");	\
+	_Static_assert(sizeof((dst).fld) == sizeof(uint64_t),	\
+	    "FU64_CP dst: " #dst "." #fld "is not 8 bytes");	\
+	memcpy(&(dst).fld, &(src).fld, sizeof(uint64_t));	\
+} while (0)
+
 #define	BT_CP(src, dst, fld) do {				\
 	CP((src).fld, (dst).fld, sec);				\
 	*(uint64_t *)&(dst).fld.frac[0] = (src).fld.frac;	\