Merge v6.17.2linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/lib/crc/x86/crc-pclmul-template.h b/lib/crc/x86/crc-pclmul-template.h
new file mode 100644
index 000000000000..35c950d7010c
--- /dev/null
+++ b/lib/crc/x86/crc-pclmul-template.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Macros for accessing the [V]PCLMULQDQ-based CRC functions that are
+ * instantiated by crc-pclmul-template.S
+ *
+ * Copyright 2025 Google LLC
+ *
+ * Author: Eric Biggers <ebiggers@google.com>
+ */
+#ifndef _CRC_PCLMUL_TEMPLATE_H
+#define _CRC_PCLMUL_TEMPLATE_H
+
+#include <asm/cpufeatures.h>
+#include <asm/simd.h>
+#include <crypto/internal/simd.h>
+#include <linux/static_call.h>
+#include "crc-pclmul-consts.h"
+
+#define DECLARE_CRC_PCLMUL_FUNCS(prefix, crc_t)				\
+crc_t prefix##_pclmul_sse(crc_t crc, const u8 *p, size_t len,		\
+			  const void *consts_ptr);			\
+crc_t prefix##_vpclmul_avx2(crc_t crc, const u8 *p, size_t len,		\
+			    const void *consts_ptr);			\
+crc_t prefix##_vpclmul_avx512(crc_t crc, const u8 *p, size_t len,	\
+			      const void *consts_ptr);			\
+DEFINE_STATIC_CALL(prefix##_pclmul, prefix##_pclmul_sse)
+
+static inline bool have_vpclmul(void)
+{
+	return boot_cpu_has(X86_FEATURE_VPCLMULQDQ) &&
+	       boot_cpu_has(X86_FEATURE_AVX2) &&
+	       cpu_has_xfeatures(XFEATURE_MASK_YMM, NULL);
+}
+
+static inline bool have_avx512(void)
+{
+	return boot_cpu_has(X86_FEATURE_AVX512BW) &&
+	       boot_cpu_has(X86_FEATURE_AVX512VL) &&
+	       !boot_cpu_has(X86_FEATURE_PREFER_YMM) &&
+	       cpu_has_xfeatures(XFEATURE_MASK_AVX512, NULL);
+}
+
+/*
+ * Call a [V]PCLMULQDQ optimized CRC function if the data length is at least 16
+ * bytes, the CPU has PCLMULQDQ support, and the current context may use SIMD.
+ *
+ * 16 bytes is the minimum length supported by the [V]PCLMULQDQ functions.
+ * There is overhead associated with kernel_fpu_begin() and kernel_fpu_end(),
+ * varying by CPU and factors such as which parts of the "FPU" state userspace
+ * has touched, which could result in a larger cutoff being better.  Indeed, a
+ * larger cutoff is usually better for a *single* message.  However, the
+ * overhead of the FPU section gets amortized if multiple FPU sections get
+ * executed before returning to userspace, since the XSAVE and XRSTOR occur only
+ * once.  Considering that and the fact that the [V]PCLMULQDQ code is lighter on
+ * the dcache than the table-based code is, a 16-byte cutoff seems to work well.
+ */
+#define CRC_PCLMUL(crc, p, len, prefix, consts, have_pclmulqdq)		\
+do {									\
+	if ((len) >= 16 && static_branch_likely(&(have_pclmulqdq)) &&	\
+	    crypto_simd_usable()) {					\
+		const void *consts_ptr;					\
+									\
+		consts_ptr = (consts).fold_across_128_bits_consts;	\
+		kernel_fpu_begin();					\
+		crc = static_call(prefix##_pclmul)((crc), (p), (len),	\
+						   consts_ptr);		\
+		kernel_fpu_end();					\
+		return crc;						\
+	}								\
+} while (0)
+
+#endif /* _CRC_PCLMUL_TEMPLATE_H */