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From:   Nathan Chancellor <nathan@kernel.org>
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Tianjia Zhang <tianjia.zhang@linux.alibaba.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com, llvm@lists.linux.dev,
        Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH] crypto: sm4 - Do not change section of ck and sbox
Date:   Wed, 25 Aug 2021 13:38:59 -0700
Message-Id: <20210825203859.416449-1-nathan@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When building with clang and GNU as, there is a warning about ignored
changed section attributes:

/tmp/sm4-c916c8.s: Assembler messages:
/tmp/sm4-c916c8.s:677: Warning: ignoring changed section attributes for
.data..cacheline_aligned

"static const" places the data in .rodata but __cacheline_aligned has
the section attribute to place it in .data..cacheline_aligned, in
addition to the aligned attribute.

To keep the alignment but avoid attempting to change sections, use the
____cacheline_aligned attribute, which is just the aligned attribute.

Fixes: 2b31277af577 ("crypto: sm4 - create SM4 library based on sm4 generic code")
Link: https://github.com/ClangBuiltLinux/linux/issues/1441
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 lib/crypto/sm4.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/crypto/sm4.c b/lib/crypto/sm4.c
index 633b59fed9db..284e62576d0c 100644
--- a/lib/crypto/sm4.c
+++ b/lib/crypto/sm4.c
@@ -15,7 +15,7 @@ static const u32 fk[4] = {
 	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
 };
 
-static const u32 __cacheline_aligned ck[32] = {
+static const u32 ____cacheline_aligned ck[32] = {
 	0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
 	0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
 	0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
@@ -26,7 +26,7 @@ static const u32 __cacheline_aligned ck[32] = {
 	0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
 };
 
-static const u8 __cacheline_aligned sbox[256] = {
+static const u8 ____cacheline_aligned sbox[256] = {
 	0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
 	0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
 	0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,

base-commit: abfc7fad63940b8dfdfd25da6f0fa813d9561645
-- 
2.33.0