[PATCHv2] arm: crypto: Add optimized SHA-256/224

[Ard Biesheuvel]

On 27 March 2015 at 11:44, Ard Biesheuvel <ard.biesheuvel at linaro.org> wrote:
> On 27 March 2015 at 11:42, Andy Polyakov <appro at openssl.org> wrote:
>>>> Could you share the error log please?
>>>
>>> OK, I spotted one issue with this code:
>>>
>>> arch/arm/crypto/sha256-core.S: Assembler messages:
>>> arch/arm/crypto/sha256-core.S:1847: Error: invalid constant (ffffefb0)
>>> after fixup
>>>
>>> This is caused by the fact that, when building the integer-only code
>>> for an older architecture, the conditional compilation produces a
>>> slightly bigger preceding function, and the symbol K256 is out of
>>> range for the adr instruction.
>>>
>>> @Jean-Christophe: is that the same problem that you hit?
>>>
>>> @Andy: I propose we do something similar as in the bsaes code:
>>>
>>> #ifdef __thumb__
>>> #define adrl adr
>>> #endif
>>>
>>> and replace the offending line with
>>>
>>> adrl r14,K256
>>
>> Sorry about delay. Yes, that would do. I did test all combinations, but
>> all "my" combinations, i.e. without __KERNEL__ defined :-( And without
>> __KERNEL__ there are few extra instructions in integer-only subroutine
>> that "push" instruction in question code toward higher address, so that
>> constant was ffffefc0, which can be encoded. Anyway, I've chosen to add
>> that #define next to .thumb directive. See attached.
>>
>> Ard, you have mentioned that you've verified it on big-endian, but I've
>> spotted little-endian dependency (see #ifndef __ARMEB__ in attached). I
>> guess that it worked for you either because it was NEON that was tested
>> (it does work as is) or __LINUX_ARM_ARCH__ was less than 7 (in which
>> case it uses endian-neutral byte-by-byte data load). Can you confirm either?
>>
>
> I need to double check that, but my suspicion is that it was the latter.

Indeed, if I build for v7 I get

[    0.269418] 00000000: 4e a5 c5 08 a6 56 6e 76 24 05 43 f8 fe b0 6f d4
[    0.275261] 00000010: 57 77 7b e3 95 49 c4 01 64 36 af da 65 d2 33 0e
[    0.281031] alg: hash: Test 1 failed for sha224-asm
[    0.285315] 00000000: 9d 6a 5d e9 e1 6c 39 99 c7 14 84 0f 47 77 1f 36
[    0.290912] 00000010: dc c2 97 a7 bd ef aa c3 6c 95 15 ae

which is indeed the integer code failing, and your attached patch fixes it.