git: 55b79ced0048 - stable/12 - md driver compat32: fix structure padding for arm, powerpc

The branch stable/12 has been updated by karels:

URL: https://cgit.FreeBSD.org/src/commit/?id=55b79ced0048e9015053ccfd96cf7f38be49ecbf

commit 55b79ced0048e9015053ccfd96cf7f38be49ecbf
Author:     Mike Karels <karels@FreeBSD.org>
AuthorDate: 2023-08-08 14:09:03 +0000
Commit:     Mike Karels <karels@FreeBSD.org>
CommitDate: 2023-08-18 12:41:06 +0000

    md driver compat32: fix structure padding for arm, powerpc
    
    Because the 32-bit md_ioctl structure contains 64-bit members, arm
    and powerpc add padding to a multiple of 8.  i386 doesn't do this.
    The md_ioctl32 definition was correct for amd64/i386 without padding,
    but wrong for arm64 and powerpc64.  Make __packed__ conditional on
    __amd64__, and test for the expected size on non-amd64.  Note that
    mdconfig is used in the ATF test suite.  Note, I verified the
    structure size for powerpc, but was unable to test.
    
    Reviewed by:    jrtc27
    Differential Revision:  https://reviews.freebsd.org/D41339
    Discussed with: jhibbits
    
    (cherry picked from commit 58a46cfd751ac726ddca8544bf73a290b0154a57)
---
 sys/dev/md/md.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 641dff4f45d3..73e3bf578019 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -145,8 +145,16 @@ struct md_ioctl32 {
 	int		md_fwsectors;
 	uint32_t	md_label;
 	int		md_pad[MDNPAD];
-} __attribute__((__packed__));
+}
+#ifdef __amd64__
+__attribute__((__packed__))
+#endif
+;
+#ifndef __amd64__
+CTASSERT((sizeof(struct md_ioctl32)) == 440);
+#else
 CTASSERT((sizeof(struct md_ioctl32)) == 436);
+#endif
 
 #define	MDIOCATTACH_32	_IOC_NEWTYPE(MDIOCATTACH, struct md_ioctl32)
 #define	MDIOCDETACH_32	_IOC_NEWTYPE(MDIOCDETACH, struct md_ioctl32)