Re: [PATCH v3 5/6] Initialize the mapping of KASan shadow memory
From: Russell King - ARM Linux
Date: Mon Apr 02 2018 - 14:16:18 EST
On Mon, Apr 02, 2018 at 02:08:13PM -0400, Nicolas Pitre wrote:
> On Mon, 2 Apr 2018, Abbott Liu wrote:
>
> > index c79b829..20161e2 100644
> > --- a/arch/arm/kernel/head-common.S
> > +++ b/arch/arm/kernel/head-common.S
> > @@ -115,6 +115,9 @@ __mmap_switched:
> > str r8, [r2] @ Save atags pointer
> > cmp r3, #0
> > strne r10, [r3] @ Save control register values
> > +#ifdef CONFIG_KASAN
> > + bl kasan_early_init
> > +#endif
> > mov lr, #0
> > b start_kernel
> > ENDPROC(__mmap_switched)
>
> Would be better if lr was cleared before calling kasan_early_init.
No. The code is correct - please remember that "bl" writes to LR.
The point of clearing LR here is to ensure that start_kernel is called
with a zero link register, which it won't be if kasan_early_init is
moved after it.
--
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