Re: [PATCH] x86/boot: Rename overlapping memcpy() to memmove()

[Kees Cook]

On Sat, Apr 23, 2016 at 4:08 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
>> --- a/arch/x86/boot/compressed/string.c
>> +++ b/arch/x86/boot/compressed/string.c
>> @@ -1,7 +1,13 @@
>> +/*
>> + * This provides an optimized implementation of memcpy, and a simplified
>> + * implementation of memset and memmove, to avoid problems with the
>> + * built-in implementations when running in the restricted decompression
>> + * stub environment.
>> + */
>
> Does 'built in' here mean the compiler's implementation?
>
> We cannot call kernel built-in functions yet, so we have to duplicate everything
> we might need, right?

Right, I actually mean both: we can use neither gcc nor kernel
built-ins. (I am fuzzy on why the gcc built-ins aren't available -- I
think because they're not available for standalone builds.)

-Kees

>
> Thanks,
>
>         Ingo



-- 
Kees Cook
Chrome OS & Brillo Security