linux-kernel - Re: [PATCH 5.7 v2] x86/crypto: aesni: Fix build with LLVM

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Message-ID: <CAKwvOdmR10E2uzKnq2Jt0DSw9+3uvjSfqidxppCoYmhNZPLx5Q@mail.gmail.com>
Date:   Tue, 23 Jun 2020 11:43:58 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Sedat Dilek <sedat.dilek@...il.com>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Craig Topper <craig.topper@...el.com>,
        Craig Topper <craig.topper@...il.com>
Subject: Re: [PATCH 5.7 v2] x86/crypto: aesni: Fix build with LLVM_IAS=1

On Mon, Jun 22, 2020 at 7:56 PM Sedat Dilek <sedat.dilek@...il.com> wrote:
>
> When building with LLVM_IAS=1 means using Clang's Integrated Assembly (IAS)
> from LLVM/Clang >= v10.0.1-rc1+ instead of GNU/as from GNU/binutils
> I see the following breakage in Debian/testing AMD64:
>
> <instantiation>:15:74: error: too many positional arguments
>  PRECOMPUTE 8*3+8(%rsp), %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7,
>                                                                          ^
>  arch/x86/crypto/aesni-intel_asm.S:1598:2: note: while in macro instantiation
>  GCM_INIT %r9, 8*3 +8(%rsp), 8*3 +16(%rsp), 8*3 +24(%rsp)
>  ^
> <instantiation>:47:2: error: unknown use of instruction mnemonic without a size suffix
>  GHASH_4_ENCRYPT_4_PARALLEL_dec %xmm9, %xmm10, %xmm11, %xmm12, %xmm13, %xmm14, %xmm0, %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7, %xmm8, enc
>  ^
> arch/x86/crypto/aesni-intel_asm.S:1599:2: note: while in macro instantiation
>  GCM_ENC_DEC dec
>  ^
> <instantiation>:15:74: error: too many positional arguments
>  PRECOMPUTE 8*3+8(%rsp), %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7,
>                                                                          ^
> arch/x86/crypto/aesni-intel_asm.S:1686:2: note: while in macro instantiation
>  GCM_INIT %r9, 8*3 +8(%rsp), 8*3 +16(%rsp), 8*3 +24(%rsp)
>  ^
> <instantiation>:47:2: error: unknown use of instruction mnemonic without a size suffix
>  GHASH_4_ENCRYPT_4_PARALLEL_enc %xmm9, %xmm10, %xmm11, %xmm12, %xmm13, %xmm14, %xmm0, %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7, %xmm8, enc
>  ^
> arch/x86/crypto/aesni-intel_asm.S:1687:2: note: while in macro instantiation
>  GCM_ENC_DEC enc
>
> Craig Topper suggested me in ClangBuiltLinux issue #1050:
>
> > I think the "too many positional arguments" is because the parser isn't able
> > to handle the trailing commas.
> >
> > The "unknown use of instruction mnemonic" is because the macro was named
> > GHASH_4_ENCRYPT_4_PARALLEL_DEC but its being instantiated with
> > GHASH_4_ENCRYPT_4_PARALLEL_dec I guess gas ignores case on the
> > macro instantiation, but llvm doesn't.
>
> First, I removed the trailing comma in the PRECOMPUTE line.
>
> Second, I substituted:
> 1. GHASH_4_ENCRYPT_4_PARALLEL_DEC -> GHASH_4_ENCRYPT_4_PARALLEL_dec
> 2. GHASH_4_ENCRYPT_4_PARALLEL_ENC -> GHASH_4_ENCRYPT_4_PARALLEL_enc
>
> With these changes I was able to build with LLVM_IAS=1 and boot on bare metal.
>
> I confirmed that this works with Linux-kernel v5.7.5 final.
>
> NOTE: This patch is on top of Linux v5.7 final.

Thanks for the note, still applies cleanly on top of linux-next today for me.

>
> Thanks to Craig and especially Nick for double-checking and his comments.
>
> Suggested-by: Craig Topper <craig.topper@...el.com>
> Suggested-by: Craig Topper <craig.topper@...il.com>
> Suggested-by: Nick Desaulniers ndesaulniers@...gle.com

^ oh, may have missed <> around email addr.

> Cc: "ClangBuiltLinux" <clang-built-linux@...glegroups.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1050
> Signed-off-by: Sedat Dilek <sedat.dilek@...il.com>

Following the same testing methodology from V1
(https://lore.kernel.org/patchwork/comment/1456822/) I verified for
GCC+GAS this is no functional change.

$ wget https://lore.kernel.org/patchwork/patch/1261340/mbox/ -O sedat_v3.patch
$ git am sedat_v3.patch
$ make -j71 arch/x86/crypto/aesni-intel_asm.o
$ llvm-objdump -dr arch/x86/crypto/aesni-intel_asm.o > postpatch_v3.txt
$ diff -u <(cat prepatch.txt | tr -s ' ' | cut -d '    ' -f 2-) <(cat
postpatch_v3.txt| tr -s ' ' | cut -d '   ' -f 2-) | less
(no output)

Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

> ---
>  arch/x86/crypto/aesni-intel_asm.S | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/crypto/aesni-intel_asm.S b/arch/x86/crypto/aesni-intel_asm.S
> index cad6e1bfa7d5..c216de287742 100644
> --- a/arch/x86/crypto/aesni-intel_asm.S
> +++ b/arch/x86/crypto/aesni-intel_asm.S
> @@ -266,7 +266,7 @@ ALL_F:      .octa 0xffffffffffffffffffffffffffffffff
>         PSHUFB_XMM %xmm2, %xmm0
>         movdqu %xmm0, CurCount(%arg2) # ctx_data.current_counter = iv
>
> -       PRECOMPUTE \SUBKEY, %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7,
> +       PRECOMPUTE \SUBKEY, %xmm1, %xmm2, %xmm3, %xmm4, %xmm5, %xmm6, %xmm7
>         movdqu HashKey(%arg2), %xmm13
>
>         CALC_AAD_HASH %xmm13, \AAD, \AADLEN, %xmm0, %xmm1, %xmm2, %xmm3, \
> @@ -978,7 +978,7 @@ _initial_blocks_done\@:
>  * arg1, %arg3, %arg4 are used as pointers only, not modified
>  * %r11 is the data offset value
>  */
> -.macro GHASH_4_ENCRYPT_4_PARALLEL_ENC TMP1 TMP2 TMP3 TMP4 TMP5 \
> +.macro GHASH_4_ENCRYPT_4_PARALLEL_enc TMP1 TMP2 TMP3 TMP4 TMP5 \
>  TMP6 XMM0 XMM1 XMM2 XMM3 XMM4 XMM5 XMM6 XMM7 XMM8 operation
>
>         movdqa    \XMM1, \XMM5
> @@ -1186,7 +1186,7 @@ aes_loop_par_enc_done\@:
>  * arg1, %arg3, %arg4 are used as pointers only, not modified
>  * %r11 is the data offset value
>  */
> -.macro GHASH_4_ENCRYPT_4_PARALLEL_DEC TMP1 TMP2 TMP3 TMP4 TMP5 \
> +.macro GHASH_4_ENCRYPT_4_PARALLEL_dec TMP1 TMP2 TMP3 TMP4 TMP5 \
>  TMP6 XMM0 XMM1 XMM2 XMM3 XMM4 XMM5 XMM6 XMM7 XMM8 operation
>
>         movdqa    \XMM1, \XMM5
> --

-- 
Thanks,
~Nick Desaulniers