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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v1] usb: Guarantee alignment of the string descriptor
Date: Thu, 29 Aug 2019 17:46:07 +0300	[thread overview]
Message-ID: <20190829144607.36233-1-andriy.shevchenko@linux.intel.com> (raw)

GCC 9.x starts complaining about potential misalignment of the pointer to the
array (in this case alignment=2) in the packed (alignment=1) structures.

drivers/usb/gadget/composite.c:545:23: warning: taking address of packed member of ‘struct usb_string_descriptor’ may result in an unaligned pointer value [-Waddress-of-packed-member]
  545 |    collect_langs(sp, s->wData);

drivers/usb/gadget/composite.c:550:24: warning: taking address of packed member of ‘struct usb_string_descriptor’ may result in an unaligned pointer value [-Waddress-of-packed-member]
  550 |     collect_langs(sp, s->wData);

drivers/usb/gadget/composite.c:555:25: warning: taking address of packed member of ‘struct usb_string_descriptor’ may result in an unaligned pointer value [-Waddress-of-packed-member]
  555 |      collect_langs(sp, s->wData);

Define structure alignment to be 2 to guarantee alignment of its members.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/usb/ch9.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index 264c9712a3..a9b3c2709a 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -336,7 +336,7 @@ struct usb_string_descriptor {
 	__u8  bDescriptorType;
 
 	__le16 wData[1];		/* UTF-16LE encoded */
-} __attribute__ ((packed));
+} __attribute__ ((packed, aligned(2)));
 
 /* note that "string" zero is special, it holds language codes that
  * the device supports, not Unicode characters.
-- 
2.23.0.rc1

             reply	other threads:[~2019-08-29 14:46 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-29 14:46 Andy Shevchenko [this message]
2019-08-30  7:16 ` [U-Boot] [PATCH v1] usb: Guarantee alignment of the string descriptor Bin Meng

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