[PATCH 6.6] raid6: add missing vzeroupper to AVX2 code

[PATCH 6.6] raid6: add missing vzeroupper to AVX2 code

[Eric Biggers]

commit 24f1241cdb056fd630e6710a916e0f7c8c910a70 upstream.

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.

Link: https://lore.kernel.org/20260831212308.213855-1-ebiggers@kernel.org
Fixes: 2c935842bdb4 ("lib/raid6: Add AVX2 optimized gen_syndrome functions")
Fixes: 7056741fd9fc ("lib/raid6: Add AVX2 optimized recovery functions")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
---
 lib/raid6/avx2.c       | 6 ++++++
 lib/raid6/recov_avx2.c | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/lib/raid6/avx2.c b/lib/raid6/avx2.c
index 059024234dce1..2d03ce97f655d 100644
--- a/lib/raid6/avx2.c
+++ b/lib/raid6/avx2.c
@@ -76,6 +76,7 @@ static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -124,6 +125,7 @@ static void raid6_avx21_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -186,6 +188,7 @@ static void raid6_avx22_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -254,6 +257,7 @@ static void raid6_avx22_xor_syndrome(int disks, int start, int stop,
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -347,6 +351,7 @@ static void raid6_avx24_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	}
 
 	asm volatile("sfence" : : : "memory");
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -457,6 +462,7 @@ 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/raid6/recov_avx2.c b/lib/raid6/recov_avx2.c
index 4e8095403ee28..a7fd1ba177f1b 100644
--- a/lib/raid6/recov_avx2.c
+++ b/lib/raid6/recov_avx2.c
@@ -180,6 +180,7 @@ static void raid6_2data_recov_avx2(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 
@@ -297,6 +298,7 @@ static void raid6_datap_recov_avx2(int disks, size_t bytes, int faila,
 #endif
 	}
 
+	asm volatile("vzeroupper");
 	kernel_fpu_end();
 }
 

base-commit: 5139929c698c273e07cb0635732f6a918a7b8e78
-- 
2.56.0