[PATCH 0/6] x86: add missing vzeroupper instructions

[PATCH 0/6] x86: add missing vzeroupper instructions

[Eric Biggers]

Assembly code using YMM or ZMM registers is supposed to end with the
vzeroupper instruction in order to avoid degrading the performance of
any later SSE code.  Since this only affects performance and not
correctness, it is sometimes overlooked.  Most kernel code does it
correctly, but a few cases were missed.  This series fixes them.

It should be easiest to take the full series through the x86 tree.

Eric Biggers (6):
  xor: add missing vzeroupper to AVX code
  raid6: add missing vzeroupper to AVX2 code
  raid6: add missing vzeroupper to AVX-512 code
  crypto: x86/aria - add missing vzeroupper in AVX2 code
  crypto: x86/aria - add missing vzeroupper in AVX-512 code
  netfilter: nft_set_pipapo_avx2: add missing vzeroupper

 arch/x86/crypto/aria-aesni-avx2-asm_64.S  |  6 ++++++
 arch/x86/crypto/aria-gfni-avx512-asm_64.S |  3 +++
 lib/raid/raid6/x86/avx2.c                 |  6 ++++++
 lib/raid/raid6/x86/avx512.c               |  6 ++++++
 lib/raid/raid6/x86/recov_avx2.c           |  2 ++
 lib/raid/raid6/x86/recov_avx512.c         |  2 ++
 lib/raid/xor/x86/xor-avx.c                |  1 +
 net/netfilter/nft_set_pipapo_avx2.c       | 17 ++++++++---------
 8 files changed, 34 insertions(+), 9 deletions(-)


base-commit: db2ddb87143519e20a95aa36c60b36107b736a58
-- 
2.55.0

[PATCH 1/6] xor: add missing vzeroupper to AVX code

[Eric Biggers]

Since the AVX optimized XOR code uses YMM registers, execute vzeroupper
before returning from it.  This is needed to avoid degrading the
performance of any later SSE code that may happen to be executed.

Fixes: ea4d26ae24e5 ("raid5: add AVX optimized RAID5 checksumming")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 lib/raid/xor/x86/xor-avx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/raid/xor/x86/xor-avx.c b/lib/raid/xor/x86/xor-avx.c
index f7777d7aa269..95b21e7225e8 100644
--- a/lib/raid/xor/x86/xor-avx.c
+++ b/lib/raid/xor/x86/xor-avx.c
@@ -147,6 +147,7 @@ static void xor_gen_avx(void *dest, void **srcs, unsigned int src_cnt,
 {
 	kernel_fpu_begin();
 	xor_gen_avx_inner(dest, srcs, src_cnt, bytes);
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
-- 
2.55.0

[PATCH 2/6] raid6: add missing vzeroupper to AVX2 code

[Eric Biggers]

Since the AVX2 optimized RAID6 code uses YMM registers, execute
vzeroupper before returning from it.  This is needed to avoid degrading
the performance of any later SSE code that may happen to be executed.

Fixes: 2c935842bdb4 ("lib/raid6: Add AVX2 optimized gen_syndrome functions")
Fixes: 7056741fd9fc ("lib/raid6: Add AVX2 optimized recovery functions")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 lib/raid/raid6/x86/avx2.c       | 6 ++++++
 lib/raid/raid6/x86/recov_avx2.c | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/lib/raid/raid6/x86/avx2.c b/lib/raid/raid6/x86/avx2.c
index 7d829c669ea7..3cc2fe7ac42c 100644
--- a/lib/raid/raid6/x86/avx2.c
+++ b/lib/raid/raid6/x86/avx2.c
@@ -67,6 +67,7 @@ static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -115,6 +116,7 @@ static void raid6_avx21_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -175,6 +177,7 @@ static void raid6_avx22_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -243,6 +246,7 @@ static void raid6_avx22_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -334,6 +338,7 @@ static void raid6_avx24_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -444,6 +449,7 @@ static void raid6_avx24_xor_syndrome(int disks, int start, int stop,
 		asm volatile("vmovntdq %%ymm14,%0" : "=m" (q[d+96]));
 	}
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
diff --git a/lib/raid/raid6/x86/recov_avx2.c b/lib/raid/raid6/x86/recov_avx2.c
index a714a780a2d8..820871046e30 100644
--- a/lib/raid/raid6/x86/recov_avx2.c
+++ b/lib/raid/raid6/x86/recov_avx2.c
@@ -176,6 +176,7 @@ static void raid6_2data_recov_avx2(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -293,6 +294,7 @@ static void raid6_datap_recov_avx2(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
-- 
2.55.0

[PATCH 3/6] raid6: add missing vzeroupper to AVX-512 code

[Eric Biggers]

Since the AVX-512 optimized RAID6 code uses ZMM registers, execute
vzeroupper before returning from it.  This is needed to avoid degrading
the performance of any later SSE code that may happen to be executed.

Fixes: e0a491c12968 ("lib/raid6: Add AVX512 optimized gen_syndrome functions")
Fixes: 13c520b2993c ("lib/raid6: Add AVX512 optimized recovery functions")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 lib/raid/raid6/x86/avx512.c       | 6 ++++++
 lib/raid/raid6/x86/recov_avx512.c | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/lib/raid/raid6/x86/avx512.c b/lib/raid/raid6/x86/avx512.c
index e671eb5bde63..772bfc4af6df 100644
--- a/lib/raid/raid6/x86/avx512.c
+++ b/lib/raid/raid6/x86/avx512.c
@@ -78,6 +78,7 @@ static void raid6_avx5121_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -137,6 +138,7 @@ static void raid6_avx5121_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -208,6 +210,7 @@ static void raid6_avx5122_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -292,6 +295,7 @@ static void raid6_avx5122_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -396,6 +400,7 @@ static void raid6_avx5124_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -529,6 +534,7 @@ static void raid6_avx5124_xor_syndrome(int disks, int start, int stop,
 			       "m" (q[d+128]), "m" (q[d+192]));
 	}
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 const struct raid6_calls raid6_avx512x4 = {
diff --git a/lib/raid/raid6/x86/recov_avx512.c b/lib/raid/raid6/x86/recov_avx512.c
index ec72d5a30c01..299a3f044d61 100644
--- a/lib/raid/raid6/x86/recov_avx512.c
+++ b/lib/raid/raid6/x86/recov_avx512.c
@@ -211,6 +211,7 @@ static void raid6_2data_recov_avx512(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -353,6 +354,7 @@ static void raid6_datap_recov_avx512(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
-- 
2.55.0

[PATCH 4/6] crypto: x86/aria - add missing vzeroupper in AVX2 code

[Eric Biggers]

Since the AVX2 optimized ARIA code uses YMM registers, execute
vzeroupper before returning from it.  This is needed to avoid degrading
the performance of any later SSE code that may happen to be executed.

Fixes: 37d8d3ae7a58 ("crypto: x86/aria - implement aria-avx2")
Cc: stable@vger.kernel.org
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 arch/x86/crypto/aria-aesni-avx2-asm_64.S | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/crypto/aria-aesni-avx2-asm_64.S b/arch/x86/crypto/aria-aesni-avx2-asm_64.S
index ed53d4f46bd7..fda8cb8a99a8 100644
--- a/arch/x86/crypto/aria-aesni-avx2-asm_64.S
+++ b/arch/x86/crypto/aria-aesni-avx2-asm_64.S
@@ -982,6 +982,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_encrypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_encrypt_32way)
@@ -1007,6 +1008,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_decrypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_decrypt_32way)
@@ -1209,6 +1211,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_ctr_crypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %r10);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_ctr_crypt_32way)
@@ -1359,6 +1362,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_gfni_encrypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_gfni_encrypt_32way)
@@ -1384,6 +1388,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_gfni_decrypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_gfni_decrypt_32way)
@@ -1428,6 +1433,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_gfni_ctr_crypt_32way)
 		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
 		     %ymm15, %r10);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_aesni_avx2_gfni_ctr_crypt_32way)
-- 
2.55.0

[PATCH 5/6] crypto: x86/aria - add missing vzeroupper in AVX-512 code

[Eric Biggers]

Since the AVX-512 optimized ARIA code uses ZMM registers, execute
vzeroupper before returning from it.  This is needed to avoid degrading
the performance of any later SSE code that may happen to be executed.

Fixes: c970d42001f2 ("crypto: x86/aria - implement aria-avx512")
Cc: stable@vger.kernel.org
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 arch/x86/crypto/aria-gfni-avx512-asm_64.S | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/crypto/aria-gfni-avx512-asm_64.S b/arch/x86/crypto/aria-gfni-avx512-asm_64.S
index 860887e5d02e..ca83eb126e06 100644
--- a/arch/x86/crypto/aria-gfni-avx512-asm_64.S
+++ b/arch/x86/crypto/aria-gfni-avx512-asm_64.S
@@ -800,6 +800,7 @@ SYM_TYPED_FUNC_START(aria_gfni_avx512_encrypt_64way)
 		     %zmm9, %zmm8, %zmm11, %zmm10, %zmm12, %zmm13, %zmm14,
 		     %zmm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_gfni_avx512_encrypt_64way)
@@ -825,6 +826,7 @@ SYM_TYPED_FUNC_START(aria_gfni_avx512_decrypt_64way)
 		     %zmm9, %zmm8, %zmm11, %zmm10, %zmm12, %zmm13, %zmm14,
 		     %zmm15, %rax);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_gfni_avx512_decrypt_64way)
@@ -966,6 +968,7 @@ SYM_TYPED_FUNC_START(aria_gfni_avx512_ctr_crypt_64way)
 		     %zmm9, %zmm8, %zmm11, %zmm10, %zmm12, %zmm13, %zmm14,
 		     %zmm15, %r10);
 
+	vzeroupper;
 	FRAME_END
 	RET;
 SYM_FUNC_END(aria_gfni_avx512_ctr_crypt_64way)
-- 
2.55.0

[PATCH 6/6] netfilter: nft_set_pipapo_avx2: add missing vzeroupper

[Eric Biggers]

Since pipapo_get_avx2() uses YMM registers, execute vzeroupper before
returning from it.  This is needed to avoid degrading the performance of
any later SSE code that may happen to be executed.

Fixes: 7400b063969b ("nft_set_pipapo: Introduce AVX2-based lookup implementation")
Cc: stable@vger.kernel.org
Cc: Florian Westphal <fw@strlen.de>
Cc: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 net/netfilter/nft_set_pipapo_avx2.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index b3f105520a85..21f5be68c703 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1134,6 +1134,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 	struct nft_pipapo_scratch *scratch;
 	const struct nft_pipapo_field *f;
 	unsigned long *res, *fill, *map;
+	struct nft_pipapo_elem *e;
 	bool map_index;
 	int ret = 0;
 	int i;
@@ -1207,14 +1208,11 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 next_match:
 		if (ret < 0) {
 			scratch->map_index = map_index;
-			kernel_fpu_end();
-			__local_unlock_nested_bh(&scratch->bh_lock);
-			return NULL;
+			e = NULL;
+			goto out;
 		}
 
 		if (last) {
-			struct nft_pipapo_elem *e;
-
 			e = f->mt[ret].e;
 			if (unlikely(__nft_set_elem_expired(&e->ext, tstamp) ||
 				     !nft_set_elem_active(&e->ext, genmask))) {
@@ -1224,9 +1222,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 			}
 
 			scratch->map_index = map_index;
-			kernel_fpu_end();
-			__local_unlock_nested_bh(&scratch->bh_lock);
-			return e;
+			goto out;
 		}
 
 		map_index = !map_index;
@@ -1234,9 +1230,12 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 		data += NFT_PIPAPO_GROUPS_PADDED_SIZE(f);
 	}
 
+	e = NULL;
+out:
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 	__local_unlock_nested_bh(&scratch->bh_lock);
-	return NULL;
+	return e;
 }
 
 /**
-- 
2.55.0

Re: [PATCH 3/6] raid6: add missing vzeroupper to AVX-512 code

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Undefined behavior in inline assembly due to writing to input operands.
--

--- Patch [3]: [PATCH 3/6] raid6: add missing vzeroupper to AVX-512 code ---
commit c5b5d02d83bf2abe1380d3036a95bcf38db79ff8
Author: Eric Biggers <ebiggers@kernel.org>

raid6: add missing vzeroupper to AVX-512 code

Since the AVX-512 optimized RAID6 code uses ZMM registers, execute
vzeroupper before returning from it. This is needed to avoid degrading
the performance of any later SSE code that may happen to be executed.

Fixes: e0a491c12968 ("lib/raid6: Add AVX512 optimized gen_syndrome functions")
Fixes: 13c520b2993c ("lib/raid6: Add AVX512 optimized recovery functions")
Cc: stable@vger.kernel.org

> diff --git a/lib/raid/raid6/x86/recov_avx512.c b/lib/raid/raid6/x86/recov_avx512.c
> index ec72d5a30c01e..299a3f044d616 100644
> --- a/lib/raid/raid6/x86/recov_avx512.c
> +++ b/lib/raid/raid6/x86/recov_avx512.c
> @@ -211,6 +211,7 @@ static void raid6_2data_recov_avx512(int disks, size_t bytes, int faila,

[Severity: High]
This is a pre-existing issue, but while reviewing this code, I noticed that
earlier in this function and in raid6_datap_recov_avx512(), the inline
assembly writes to memory operands that are listed only in the input
constraints list.

For example, in raid6_2data_recov_avx512():

		asm volatile("vmovdqa64 %%zmm1, %0\n\t"
			     "vmovdqa64 %%zmm13,%1\n\t"
			     "vpxorq %%zmm1, %%zmm0, %%zmm0\n\t"
			     "vpxorq %%zmm13, %%zmm8, %%zmm8"
			     :
			     : "m" (dq[0]), "m" (dq[64]));

And in raid6_datap_recov_avx512():

		asm volatile("vmovdqa64 %%zmm1, %0\n\t"
			     "vmovdqa64 %%zmm14, %1\n\t"
			     "vmovdqa64 %%zmm2, %2\n\t"
			     "vmovdqa64 %%zmm12,%3"
			     :
			     : "m" (dq[0]), "m" (dq[64]), "m" (p[0]),
			       "m" (p[64]));

Could this cause data corruption or miscompilation?

GCC documentation forbids writing to input operands. If GCC assumes input
operands are unmodified, might it optimize away the writes, cache stale
values, or reorder accesses during RAID6 recovery?

>  #endif
>  	}
>  
> +	asm volatile("vzeroupper");
>  	kernel_fpu_end();
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260815205750.169336-1-ebiggers@kernel.org?part=3

Re: [PATCH 2/6] raid6: add missing vzeroupper to AVX2 code

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Missing vzeroupper in AVX-512 RAID6 code leading to severe AVX-SSE transition penalties
--

--- Patch [2]: [PATCH 2/6] raid6: add missing vzeroupper to AVX2 code ---
commit 053e34bcf70317a18a7c9c774075bd7eb1c95140
Author: Eric Biggers <ebiggers@kernel.org>

raid6: add missing vzeroupper to AVX2 code

Since the AVX2 optimized RAID6 code uses YMM registers, execute vzeroupper
before returning from it. This is needed to avoid degrading the performance
of any later SSE code that may happen to be executed.

> diff --git a/lib/raid/raid6/x86/avx2.c b/lib/raid/raid6/x86/avx2.c
> index 7d829c669ea79..3cc2fe7ac42c5 100644
> --- a/lib/raid/raid6/x86/avx2.c
> +++ b/lib/raid/raid6/x86/avx2.c
> @@ -67,6 +67,7 @@ static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
>  	}
>  
>  	asm volatile("sfence" : : : "memory");
> +	asm volatile("vzeroupper");

[Severity: High]
This is a pre-existing issue, but does the AVX-512 RAID6 code also need this
fix?

Like the AVX2 code, the AVX-512 code uses ZMM registers but returns without
executing vzeroupper before kernel_fpu_end().

For example, in lib/raid/raid6/x86/avx512.c:raid6_avx5121_gen_syndrome():

        asm volatile("sfence" : : : "memory");
        kernel_fpu_end();
}

And similarly in lib/raid/raid6/x86/recov_avx512.c:raid6_2data_recov_avx512().

Would omitting vzeroupper here leave the upper bits of ZMM registers dirty
and incur severe AVX-SSE transition penalties if the CPU subsequently
executes legacy SSE code, causing a performance regression?

>  	kernel_fpu_end();
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260815205750.169336-1-ebiggers@kernel.org?part=2

Re: [PATCH 4/6] crypto: x86/aria - add missing vzeroupper in AVX2 code

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Missing `vzeroupper` in the AVX-512 optimized ARIA code (`aria-gfni-avx512-asm_64.S`), causing a significant performance regression due to AVX-SSE transition penalties. This problem wasn't introduced by this patch, but the patch fixes the exact same issue in the AVX2 implementation while missing the AVX-512 code.
--

--- Patch [4]: [PATCH 4/6] crypto: x86/aria - add missing vzeroupper in AVX2 code ---
commit 92a2e79950d33a63291c62ee57a893ce808d68d2
Author: Eric Biggers <ebiggers@kernel.org>

crypto: x86/aria - add missing vzeroupper in AVX2 code

This commit adds missing vzeroupper instructions to the AVX2 ARIA assembly
code. This prevents performance degradation for any later SSE code that might
be executed by avoiding transition penalties from the YMM registers being left
in a dirty state.

> diff --git a/arch/x86/crypto/aria-aesni-avx2-asm_64.S b/arch/x86/crypto/aria-aesni-avx2-asm_64.S
> index ed53d4f46bd7c..fda8cb8a99a8a 100644
> --- a/arch/x86/crypto/aria-aesni-avx2-asm_64.S
> +++ b/arch/x86/crypto/aria-aesni-avx2-asm_64.S
[ ... ]
> @@ -1428,6 +1433,7 @@ SYM_TYPED_FUNC_START(aria_aesni_avx2_gfni_ctr_crypt_32way)
>  		     %ymm8, %ymm9, %ymm10, %ymm11, %ymm12, %ymm13, %ymm14,
>  		     %ymm15, %r10);
>  
> +	vzeroupper;
>  	FRAME_END
>  	RET;
>  SYM_FUNC_END(aria_aesni_avx2_gfni_ctr_crypt_32way)

[Severity: High]
This is a pre-existing issue, but does the AVX-512 ARIA code also need the
same fix?

Looking at arch/x86/crypto/aria-gfni-avx512-asm_64.S, the AVX-512 optimized
functions like aria_gfni_avx512_encrypt_64way(),
aria_gfni_avx512_decrypt_64way(), and aria_gfni_avx512_ctr_crypt_64way()
return without executing vzeroupper:

arch/x86/crypto/aria-gfni-avx512-asm_64.S:aria_gfni_avx512_encrypt_64way() {
    ...
	FRAME_END
	RET;
SYM_FUNC_END(aria_gfni_avx512_encrypt_64way)
}

Since zmm registers are used, wouldn't returning without clearing the EVEX
dirty state cause the same performance transition penalties for subsequent
legacy SSE code?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260815205750.169336-1-ebiggers@kernel.org?part=4