netdev - RE: [PATCH net] idpf: avoid compiler padding in virtchnl2

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Message-ID: <87cb8a4405724ccb9a00cd23dd07915c@AcuMS.aculab.com>
Date: Mon, 22 Jan 2024 23:01:26 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Tony Nguyen' <anthony.l.nguyen@...el.com>, "davem@...emloft.net"
	<davem@...emloft.net>, "kuba@...nel.org" <kuba@...nel.org>,
	"pabeni@...hat.com" <pabeni@...hat.com>, "edumazet@...gle.com"
	<edumazet@...gle.com>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC: Pavan Kumar Linga <pavan.kumar.linga@...el.com>, "willemb@...gle.com"
	<willemb@...gle.com>, kernel test robot <lkp@...el.com>, Przemek Kitszel
	<przemyslaw.kitszel@...el.com>, Paul Menzel <pmenzel@...gen.mpg.de>, "Simon
 Horman" <horms@...nel.org>, Krishneil Singh <krishneil.k.singh@...el.com>
Subject: RE: [PATCH net] idpf: avoid compiler padding in virtchnl2_ptype
 struct

From: Tony Nguyen
> Sent: 22 January 2024 17:52
> 
> In the arm random config file, kconfig option 'CONFIG_AEABI' is
> disabled which results in adding the compiler flag '-mabi=apcs-gnu'.

Isn't the arm EABI pretty much the only value used for the last
15 years at least?
Doesn't it also change the size of enums?

So perhaps it shouldn't be possible to unset it?

> This causes the compiler to add padding in virtchnl2_ptype
> structure to align it to 8 bytes, resulting in the following
> size check failure:
> 
> include/linux/build_bug.h:78:41: error: static assertion failed: "(6) == sizeof(struct
> virtchnl2_ptype)"

And turn that conditional the correct way around...

	David

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