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From: Kees Cook <keescook@chromium.org>
Date: Tue, 24 May 2016 13:55:51 -0700
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Subject: Re: [PATCH v1 2/3] Mark functions with the latent_entropy attribute
To: Emese Revfy <re.emese@gmail.com>
Cc: "kernel-hardening@lists.openwall.com" 
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On Tue, May 24, 2016 at 1:45 PM, Emese Revfy <re.emese@gmail.com> wrote:
> On Tue, 24 May 2016 10:16:09 -0700
> Kees Cook <keescook@chromium.org> wrote:
>
>> On Mon, May 23, 2016 at 3:16 PM, Emese Revfy <re.emese@gmail.com> wrote:
>> > +#ifdef CONFIG_MEMORY_HOTPLUG
>> > +#define add_meminit_latent_entropy
>> > +#else
>> > +#define add_meminit_latent_entropy __latent_entropy
>> > +#endif
>> > +
>> >  /* These are for everybody (although not all archs will actually
>> >     discard it in modules) */
>> > -#define __init         __section(.init.text) __cold notrace
>> > +#define __init         __section(.init.text) __cold notrace __latent_entropy
>> >  #define __initdata     __section(.init.data)
>> >  #define __initconst    __constsection(.init.rodata)
>> >  #define __exitdata     __section(.exit.data)
>> > @@ -92,7 +98,7 @@
>> >  #define __exit          __section(.exit.text) __exitused __cold notrace
>> >
>> >  /* Used for MEMORY_HOTPLUG */
>> > -#define __meminit        __section(.meminit.text) __cold notrace
>> > +#define __meminit        __section(.meminit.text) __cold notrace add_meminit_latent_entropy
>> >  #define __meminitdata    __section(.meminit.data)
>> >  #define __meminitconst   __constsection(.meminit.rodata)
>> >  #define __memexit        __section(.memexit.text) __exitused __cold notrace
>>
>> I was confused by these defines. :) Maybe "add_meminit_latent_entropy"
>> should be named "__memory_hotplug_only_latent_entropy" or something
>> like that?
>
> I think the plugin doesn't cause a significant slowdown when CONFIG_MEMORY_HOTPLUG is enabled so I would rather always add the __latent_entropy attribute to __meminit.

That seems fine to me. :)

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security