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Date: Wed, 11 Oct 2017 22:41:31 +0100
From: Russell King - ARM Linux <linux@armlinux.org.uk>
Subject: Re: [PATCH 01/11] Initialize the mapping of KASan shadow memory
Message-ID: <20171011214131.GV20805@n2100.armlinux.org.uk>
References: <20171011082227.20546-1-liuwenliang@huawei.com>
 <20171011082227.20546-2-liuwenliang@huawei.com>
 <b53b3281-5eef-7cbd-c7d3-5417d764667b@gmail.com>
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To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Abbott Liu <liuwenliang@huawei.com>, aryabinin@virtuozzo.com, afzal.mohd.ma@gmail.com, labbott@redhat.com, kirill.shutemov@linux.intel.com, mhocko@suse.com, cdall@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, akpm@linux-foundation.org, mawilcox@microsoft.com, tglx@linutronix.de, thgarnie@google.com, keescook@chromium.org, arnd@arndb.de, vladimir.murzin@arm.com, tixy@linaro.org, ard.biesheuvel@linaro.org, robin.murphy@arm.com, mingo@kernel.org, grygorii.strashko@linaro.org, opendmb@gmail.com, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, zengweilin@huawei.com, linux-mm@kvack.org, dylix.dailei@huawei.com, glider@google.com, dvyukov@google.com, jiazhenghua@huawei.com, linux-arm-kernel@lists.infradead.org, heshaoliang@huawei.com

On Wed, Oct 11, 2017 at 12:39:39PM -0700, Florian Fainelli wrote:
> On 10/11/2017 01:22 AM, Abbott Liu wrote:
> > diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
> > index 8733012..c17f4a2 100644
> > --- a/arch/arm/kernel/head-common.S
> > +++ b/arch/arm/kernel/head-common.S
> > @@ -101,7 +101,11 @@ __mmap_switched:
> >  	str	r2, [r6]			@ Save atags pointer
> >  	cmp	r7, #0
> >  	strne	r0, [r7]			@ Save control register values
> > +#ifdef CONFIG_KASAN
> > +	b	kasan_early_init
> > +#else
> >  	b	start_kernel
> > +#endif
> 
> Please don't make this "exclusive" just conditionally call
> kasan_early_init(), remove the call to start_kernel from
> kasan_early_init and keep the call to start_kernel here.

iow:

#ifdef CONFIG_KASAN
	bl	kasan_early_init
#endif
	b	start_kernel

This has the advantage that we don't leave any stack frame from
kasan_early_init() on the init task stack.

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