1 files changed, 124 insertions, 0 deletions
diff --git a/arch/x86/lib/crc32-glue.c b/arch/x86/lib/crc32-glue.c
new file mode 100644
index 000000000000..2dd18a886ded
--- /dev/null
+++ b/arch/x86/lib/crc32-glue.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * x86-optimized CRC32 functions
+ *
+ * Copyright (C) 2008 Intel Corporation
+ * Copyright 2012 Xyratex Technology Limited
+ * Copyright 2024 Google LLC
+ */
+
+#include <asm/cpufeatures.h>
+#include <asm/simd.h>
+#include <crypto/internal/simd.h>
+#include <linux/crc32.h>
+#include <linux/linkage.h>
+#include <linux/module.h>
+
+/* minimum size of buffer for crc32_pclmul_le_16 */
+#define CRC32_PCLMUL_MIN_LEN	64
+
+static DEFINE_STATIC_KEY_FALSE(have_crc32);
+static DEFINE_STATIC_KEY_FALSE(have_pclmulqdq);
+
+u32 crc32_pclmul_le_16(u32 crc, const u8 *buffer, size_t len);
+
+u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
+{
+	if (len >= CRC32_PCLMUL_MIN_LEN + 15 &&
+	    static_branch_likely(&have_pclmulqdq) && crypto_simd_usable()) {
+		size_t n = -(uintptr_t)p & 15;
+
+		/* align p to 16-byte boundary */
+		if (n) {
+			crc = crc32_le_base(crc, p, n);
+			p += n;
+			len -= n;
+		}
+		n = round_down(len, 16);
+		kernel_fpu_begin();
+		crc = crc32_pclmul_le_16(crc, p, n);
+		kernel_fpu_end();
+		p += n;
+		len -= n;
+	}
+	if (len)
+		crc = crc32_le_base(crc, p, len);
+	return crc;
+}
+EXPORT_SYMBOL(crc32_le_arch);
+
+#ifdef CONFIG_X86_64
+#define CRC32_INST "crc32q %1, %q0"
+#else
+#define CRC32_INST "crc32l %1, %0"
+#endif
+
+/*
+ * Use carryless multiply version of crc32c when buffer size is >= 512 to
+ * account for FPU state save/restore overhead.
+ */
+#define CRC32C_PCLMUL_BREAKEVEN	512
+
+asmlinkage u32 crc32c_x86_3way(u32 crc, const u8 *buffer, size_t len);
+
+u32 crc32c_le_arch(u32 crc, const u8 *p, size_t len)
+{
+	size_t num_longs;
+
+	if (!static_branch_likely(&have_crc32))
+		return crc32c_le_base(crc, p, len);
+
+	if (IS_ENABLED(CONFIG_X86_64) && len >= CRC32C_PCLMUL_BREAKEVEN &&
+	    static_branch_likely(&have_pclmulqdq) && crypto_simd_usable()) {
+		kernel_fpu_begin();
+		crc = crc32c_x86_3way(crc, p, len);
+		kernel_fpu_end();
+		return crc;
+	}
+
+	for (num_longs = len / sizeof(unsigned long);
+	     num_longs != 0; num_longs--, p += sizeof(unsigned long))
+		asm(CRC32_INST : "+r" (crc) : "rm" (*(unsigned long *)p));
+
+	for (len %= sizeof(unsigned long); len; len--, p++)
+		asm("crc32b %1, %0" : "+r" (crc) : "rm" (*p));
+
+	return crc;
+}
+EXPORT_SYMBOL(crc32c_le_arch);
+
+u32 crc32_be_arch(u32 crc, const u8 *p, size_t len)
+{
+	return crc32_be_base(crc, p, len);
+}
+EXPORT_SYMBOL(crc32_be_arch);
+
+static int __init crc32_x86_init(void)
+{
+	if (boot_cpu_has(X86_FEATURE_XMM4_2))
+		static_branch_enable(&have_crc32);
+	if (boot_cpu_has(X86_FEATURE_PCLMULQDQ))
+		static_branch_enable(&have_pclmulqdq);
+	return 0;
+}
+arch_initcall(crc32_x86_init);
+
+static void __exit crc32_x86_exit(void)
+{
+}
+module_exit(crc32_x86_exit);
+
+u32 crc32_optimizations(void)
+{
+	u32 optimizations = 0;
+
+	if (static_key_enabled(&have_crc32))
+		optimizations |= CRC32C_OPTIMIZATION;
+	if (static_key_enabled(&have_pclmulqdq))
+		optimizations |= CRC32_LE_OPTIMIZATION;
+	return optimizations;
+}
+EXPORT_SYMBOL(crc32_optimizations);
+
+MODULE_DESCRIPTION("x86-optimized CRC32 functions");
+MODULE_LICENSE("GPL");