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Date: Sat, 12 Nov 2016 05:43:19 +0000
From: Will Deacon <will.deacon@arm.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-kernel@vger.kernel.org, Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
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Subject: Re: [PATCH RFC] mm: Add debug_virt_to_phys()
Message-ID: <20161112054318.GB24127@arm.com>
References: <20161112004449.30566-1-f.fainelli@gmail.com>
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On Fri, Nov 11, 2016 at 04:44:43PM -0800, Florian Fainelli wrote:
> When CONFIG_DEBUG_VM is turned on, virt_to_phys() maps to
> debug_virt_to_phys() which helps catch vmalloc space addresses being
> passed. This is helpful in debugging bogus drivers that just assume
> linear mappings all over the place.
> 
> For ARM, ARM64, Unicore32 and Microblaze, the architectures define
> __virt_to_phys() as being the functional implementation of the address
> translation, so we special case the debug stub to call into
> __virt_to_phys directly.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  arch/arm/include/asm/memory.h      |  4 ++++
>  arch/arm64/include/asm/memory.h    |  4 ++++
>  include/asm-generic/memory_model.h |  4 ++++
>  mm/debug.c                         | 15 +++++++++++++++
>  4 files changed, 27 insertions(+)

What's the interaction between this and the DEBUG_VIRTUAL patches from Laura?

http://lkml.kernel.org/r/20161102210054.16621-7-labbott@redhat.com

They seem to be tackling the exact same problem afaict.

Will