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From: Stefano Stabellini <sstabellini@kernel.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: Stefano Stabellini <stefanos@xilinx.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>,
	george.dunlap@citrix.com, Tim Deegan <tim@xen.org>,
	Julien Grall <julien.grall@arm.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	ian.jackson@citrix.com
Subject: Re: [PATCH v11 1/9] xen: use __UINTPTR_TYPE__ for uintptr_t
Date: Wed, 6 Mar 2019 13:16:04 -0800 (PST)	[thread overview]
Message-ID: <alpine.DEB.2.10.1903061315100.17248@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <5C7F7B26020000780021BF3A@prv1-mh.provo.novell.com>

On Wed, 6 Mar 2019, Jan Beulich wrote:
> >>> On 05.03.19 at 23:38, <sstabellini@kernel.org> wrote:
> > Use __UINTPTR_TYPE__ to define uintptr_t. A later patch will make use of
> > __PTRDIFF_TYPE__ to define ptrdiff_t.
> > 
> > Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
> > Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
> 
> As before - I object to this change without the description supplying
> both a reason (which would better also explain why the current way
> of defining uintptr_t is detrimental) and a discussion why it is okay for
> us to use __UINTPTR_TYPE__, despite (at least) gcc making this
> available only under certain conditions (i.e. it would need to be
> confirmed that whatever the conditions they're always met for us).

Is the following good enough:

Use __UINTPTR_TYPE__ to define uintptr_t for consistency with ptrdiff_t.
__UINTPTR_TYPE__ is safe to use as it is a common predefined macro of
GNU C; it is defined to the correct underlying type as per GCC
documentation[1].

[1] https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html

Also, it is not a good idea to use __mode__(__pointer__) to define
uintptr_t, because it relies on an obscurely defined GCC feature whose
semantics might be taken to imply that the things are really pointers.


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  reply	other threads:[~2019-03-06 21:16 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-05 22:38 [PATCH v11 0/9] misc safety certification fixes Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 1/9] xen: use __UINTPTR_TYPE__ for uintptr_t Stefano Stabellini
2019-03-06  7:47   ` Jan Beulich
2019-03-06 21:16     ` Stefano Stabellini [this message]
2019-03-07  8:29       ` Jan Beulich
2019-03-07 15:43         ` Ian Jackson
2019-03-08  7:23           ` Jan Beulich
2019-03-08 14:18   ` Andrew Cooper
2019-03-08 15:19     ` Ian Jackson
2019-03-05 22:38 ` [PATCH v11 2/9] xen: introduce ptrdiff_t Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 3/9] xen: introduce DECLARE_BOUNDS Stefano Stabellini
2019-03-06 15:24   ` Jan Beulich
2019-03-06 20:55     ` Stefano Stabellini
2019-03-07  8:39       ` Jan Beulich
2019-03-07 14:16         ` Ian Jackson
2019-03-08  8:15           ` Jan Beulich
2019-03-08 15:31             ` Ian Jackson
2019-03-05 22:38 ` [PATCH v11 4/9] xen/arm: use DECLARE_BOUNDS as required Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 5/9] xen/x86: " Stefano Stabellini
2019-03-06 15:33   ` Jan Beulich
2019-03-06 21:05     ` Stefano Stabellini
2019-03-07  8:40       ` Jan Beulich
2019-03-07 14:02       ` Ian Jackson
2019-03-07 14:42         ` George Dunlap
2019-03-08  8:46         ` Jan Beulich
2019-03-08  8:55           ` Juergen Gross
2019-03-08 15:33           ` Ian Jackson
2019-03-06 15:48   ` Jan Beulich
2019-03-06 21:38     ` Stefano Stabellini
2019-03-07  8:50       ` Jan Beulich
2019-03-07 14:43         ` Ian Jackson
2019-03-08  8:22           ` Jan Beulich
2019-03-08 15:36             ` Ian Jackson
2019-03-08 15:57               ` Jan Beulich
2019-03-07 14:00       ` Ian Jackson
2019-03-08 15:43   ` Ian Jackson
2019-03-08 15:49     ` Jan Beulich
2019-03-05 22:38 ` [PATCH v11 6/9] xen/common: " Stefano Stabellini
2019-03-06 15:37   ` Jan Beulich
2019-03-06 21:08     ` Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 7/9] xen: " Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 8/9] xen: use DECLARE_BOUNDS in alternative.c Stefano Stabellini
2019-03-06 16:35   ` Jan Beulich
2019-03-06 21:38     ` Stefano Stabellini
2019-03-05 22:38 ` [PATCH v11 9/9] xen: explicit casts when DECLARE_BOUNDS cannot be used Stefano Stabellini
2019-03-07 11:40   ` Jan Beulich
2019-03-07 15:25     ` [PATCH v11 9/9] xen: explicit casts when DECLARE_BOUNDS cannot be used [and 1 more messages] Ian Jackson
2019-03-07 22:55       ` Stefano Stabellini
2019-03-08 15:39         ` [PATCH v11 9/9] xen: explicit casts when DECLARE_BOUNDS cannot be used [and 1 more messages] " Ian Jackson
2019-03-08  8:28       ` [PATCH v11 9/9] xen: explicit casts when DECLARE_BOUNDS cannot be used " Jan Beulich
2019-03-08 15:26 ` SRSL People... [PATCH v11 0/9] misc safety certification fixes Andrew Cooper
2019-03-08 15:44   ` Ian Jackson
2019-03-08 15:46   ` Jan Beulich
2019-03-08 20:14     ` Stefano Stabellini

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