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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Jason Cooper <jason@lakedaemon.net>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/1] ARM: LPAE: use phys_addr_t instead of unsigned long in outercache hooks
Date: Sat, 26 Dec 2020 12:13:46 +0000	[thread overview]
Message-ID: <20201226121346.GB1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20201225114458.1334-1-thunder.leizhen@huawei.com>

On Fri, Dec 25, 2020 at 07:44:58PM +0800, Zhen Lei wrote:
> The outercache of some Hisilicon SOCs support physical addresses wider
> than 32-bits. The unsigned long datatype is not sufficient for mapping
> physical addresses >= 4GB. The commit ad6b9c9d78b9 ("ARM: 6671/1: LPAE:
> use phys_addr_t instead of unsigned long in outercache functions") has
> already modified the outercache functions. But the parameters of the
> outercache hooks are not changed. This patch use phys_addr_t instead of
> unsigned long in outercache hooks: inv_range, clean_range, flush_range.
> 
> To ensure the outercache that does not support LPAE works properly, do
> cast phys_addr_t to unsigned long by adding a middle-tier function.

Please don't do that. The cast can be done inside the L2 functions
themselves without needing all these additional functions.

We probably ought to also add some protection against addresses > 4GB,
although these are hot paths, so we don't want to add tests in these
functions. Maybe instead checking whether the system has memory above
4GB while the L2 cache is being initialised would be a good idea?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

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  parent reply	other threads:[~2020-12-26 12:19 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-25 11:44 [PATCH 1/1] ARM: LPAE: use phys_addr_t instead of unsigned long in outercache hooks Zhen Lei
2020-12-26  2:18 ` Leizhen (ThunderTown)
2020-12-26 12:15   ` Russell King - ARM Linux admin
2020-12-29  6:31     ` Leizhen (ThunderTown)
2020-12-26 12:13 ` Russell King - ARM Linux admin [this message]
2020-12-29  6:30   ` Leizhen (ThunderTown)
2020-12-29 10:51     ` Russell King - ARM Linux admin
2020-12-30  8:08       ` Leizhen (ThunderTown)
2020-12-28  7:00 ` Arnd Bergmann
2020-12-29  6:45   ` Leizhen (ThunderTown)
2020-12-29 10:54   ` Russell King - ARM Linux admin

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