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From: Al Viro <viro@zeniv.linux.org.uk>
To: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	kernel test robot <lkp@intel.com>,
	kbuild-all@lists.01.org, linux-kernel@vger.kernel.org,
	Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of noderef expression
Date: Wed, 6 Jan 2021 20:46:59 +0000	[thread overview]
Message-ID: <20210106204659.GE3579531@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20210106201226.GA25625@arm.com>

On Wed, Jan 06, 2021 at 08:12:27PM +0000, Ionela Voinescu wrote:

> Initially I though it always only makes sense to have a __iomem pointer.
> That is, it only makes sense to have a pointer with a cookie attached
> specifying that it addresses a device memory space that should only be
> accessed using special functions.
> 
> But then you've got something like this in drivers/input/serio/apbps2.c:
> struct apbps2_regs {
> 	u32 __iomem data;	/* 0x00 */
> 	u32 __iomem status;	/* 0x04 */
> 	u32 __iomem ctrl;	/* 0x08 */
> 	u32 __iomem reload;	/* 0x0c */
> };
> struct apbps2_priv {
> 	struct serio		*io;
> 	struct apbps2_regs	*regs;
> };
> [..] (followed by)
> ioread32be(&priv->regs->status)
> 
> which I think is correct despite contradicting my assumption, but it's
> the only example I've found in the kernel.

Frankly, I would rather turn that into
	struct apbps2_regs	__iomem *regs;
and striped the individual field qualifiers...

WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: kbuild-all@lists.01.org
Subject: Re: arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of noderef expression
Date: Wed, 06 Jan 2021 20:46:59 +0000	[thread overview]
Message-ID: <20210106204659.GE3579531@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20210106201226.GA25625@arm.com>

[-- Attachment #1: Type: text/plain, Size: 962 bytes --]

On Wed, Jan 06, 2021 at 08:12:27PM +0000, Ionela Voinescu wrote:

> Initially I though it always only makes sense to have a __iomem pointer.
> That is, it only makes sense to have a pointer with a cookie attached
> specifying that it addresses a device memory space that should only be
> accessed using special functions.
> 
> But then you've got something like this in drivers/input/serio/apbps2.c:
> struct apbps2_regs {
> 	u32 __iomem data;	/* 0x00 */
> 	u32 __iomem status;	/* 0x04 */
> 	u32 __iomem ctrl;	/* 0x08 */
> 	u32 __iomem reload;	/* 0x0c */
> };
> struct apbps2_priv {
> 	struct serio		*io;
> 	struct apbps2_regs	*regs;
> };
> [..] (followed by)
> ioread32be(&priv->regs->status)
> 
> which I think is correct despite contradicting my assumption, but it's
> the only example I've found in the kernel.

Frankly, I would rather turn that into
	struct apbps2_regs	__iomem *regs;
and striped the individual field qualifiers...

  reply	other threads:[~2021-01-06 20:48 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-17 21:00 arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of noderef expression kernel test robot
2020-12-17 21:00 ` kernel test robot
2020-12-18 10:44 ` Catalin Marinas
2020-12-18 10:44   ` Catalin Marinas
2021-01-06 15:07   ` Ionela Voinescu
2021-01-06 15:07     ` Ionela Voinescu
2021-01-06 15:21     ` Catalin Marinas
2021-01-06 15:21       ` Catalin Marinas
2021-01-06 15:52       ` Ionela Voinescu
2021-01-06 15:52         ` Ionela Voinescu
2021-01-06 16:13         ` Al Viro
2021-01-06 16:13           ` Al Viro
2021-01-06 16:47           ` Ionela Voinescu
2021-01-06 16:47             ` Ionela Voinescu
2021-01-06 17:47     ` Al Viro
2021-01-06 17:47       ` Al Viro
2021-01-06 20:12       ` Ionela Voinescu
2021-01-06 20:12         ` Ionela Voinescu
2021-01-06 20:46         ` Al Viro [this message]
2021-01-06 20:46           ` Al Viro
2021-01-06  5:50 kernel test robot
2021-01-06  5:50 ` kernel test robot

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