linux-kernel - Re: [PATCH 3/3] ARM: Add support for CONFIG_DEBUG

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Message-ID: <2c5c5fe5-ad79-35f8-95b4-32c5653ddd5c@gmail.com>
Date:   Tue, 6 Dec 2016 12:42:10 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux@...linux.org.uk, nicolas.pitre@...aro.org, panand@...hat.com,
        chris.brandt@...esas.com, arnd@...db.de, jonathan.austin@....com,
        pawel.moll@....com, vladimir.murzin@....com, mark.rutland@....com,
        ard.biesheuvel@...aro.org, keescook@...omium.org,
        matt@...eblueprint.co.uk, labbott@...oraproject.org,
        kirill.shutemov@...ux.intel.com, ben@...adent.org.uk,
        js07.lee@...sung.com, stefan@...er.ch, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL

On 12/06/2016 11:53 AM, Florian Fainelli wrote:
> x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on
> virt_to_phys calls. The goal is to catch users who are calling
> virt_to_phys on non-linear addresses immediately. This includes caller
> using __virt_to_phys() on image addresses instead of __pa_symbol(). This
> is a generally useful debug feature to spot bad code (particulary in
> drivers).
> 
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---

> @@ -261,6 +261,16 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
>  	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
>  	 PHYS_PFN_OFFSET)
>  
> +#define __pa_symbol_nodebug(x)	((x) - (unsigned long)KERNEL_START)

I don't think I got this one quite right, but I also assume that won't
be the only problem with this patch series.
-- 
Florian