1 files changed, 41 insertions, 0 deletions
diff --git a/lib/libmd/amd64/md5dispatch.c b/lib/libmd/amd64/md5dispatch.c
new file mode 100644
index 000000000000..dd2131c5a57c
--- /dev/null
+++ b/lib/libmd/amd64/md5dispatch.c
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 2024 Robert Clausecker <fuz@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/types.h>
+#include <sys/md5.h>
+
+#include <machine/cpufunc.h>
+#include <machine/specialreg.h>
+#include <stdint.h>
+#include <string.h>
+#include <x86/ifunc.h>
+
+extern void _libmd_md5block_baseline(MD5_CTX *, const void *, size_t);
+extern void _libmd_md5block_bmi1(MD5_CTX *, const void *, size_t);
+extern void _libmd_md5block_avx512(MD5_CTX *, const void *, size_t);
+
+DEFINE_UIFUNC(, void, _libmd_md5block, (MD5_CTX *, const void *, size_t))
+{
+	if ((cpu_stdext_feature & (CPUID_STDEXT_AVX512F | CPUID_STDEXT_AVX512VL))
+	    == (CPUID_STDEXT_AVX512F | CPUID_STDEXT_AVX512VL)) {
+		u_int regs[4];
+		char cpu_vendor[12];
+
+		do_cpuid(0, regs);
+		((u_int *)&cpu_vendor)[0] = regs[1];
+		((u_int *)&cpu_vendor)[1] = regs[3];
+		((u_int *)&cpu_vendor)[2] = regs[2];
+
+		/* the AVX-512 kernel performs poorly on AMD */
+		if (memcmp(cpu_vendor, AMD_VENDOR_ID, sizeof(cpu_vendor)) != 0)
+			return (_libmd_md5block_avx512);
+	}
+
+	if (cpu_stdext_feature & CPUID_STDEXT_BMI1)
+		return (_libmd_md5block_bmi1);
+	else
+		return (_libmd_md5block_baseline);
+}