Add SIMD metadata in /proc on Linux

include/os/freebsd/spl/sys/simd.h

@@ -50,4 +50,7 @@
 #define	kfpu_fini()		do {} while (0)
 #endif
 
+#define	simd_stat_init()	0
+#define	simd_stat_fini()	0
+
 #endif

include/os/linux/kernel/linux/simd.h

@@ -45,4 +45,8 @@
 #define	kfpu_fini()		((void) 0)
 
 #endif
+
+void simd_stat_init(void);
+void simd_stat_fini(void);
+
 #endif /* _LINUX_SIMD_H */

lib/libspl/include/sys/simd.h

@@ -592,4 +592,7 @@ zfs_isa207_available(void)
 
 #endif
 
+extern void simd_stat_init(void);
+extern void simd_stat_fini(void);
+
 #endif /* _LIBSPL_SYS_SIMD_H */

lib/libzpool/Makefile.am

@@ -52,6 +52,7 @@ nodist_libzpool_la_SOURCES = \
 	module/os/linux/zfs/zio_crypt.c \
 	\
 	module/zcommon/cityhash.c \
+	module/zcommon/simd_stat.c \
 	module/zcommon/zfeature_common.c \
 	module/zcommon/zfs_comutil.c \
 	module/zcommon/zfs_deleg.c \

module/Kbuild.in

@@ -232,6 +232,7 @@ zfs-objs += $(addprefix unicode/,$(UNICODE_OBJS))
 
 ZCOMMON_OBJS := \
 	cityhash.o \
+	simd_stat.o \
 	zfeature_common.o \
 	zfs_comutil.o \
 	zfs_deleg.o \

module/zcommon/simd_stat.c

@@ -0,0 +1,189 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2024 Google, Inc.  All rights reserved.
+ */
+#include <sys/zfs_context.h>
+#include <sys/kstat.h>
+#include <sys/simd.h>
+
+
+#ifdef _KERNEL
+#ifdef __linux__
+#include <linux/simd.h>
+#endif /* __linux__ */
+kstat_t *simd_stat_kstat;
+#endif /* _KERNEL */
+
+#ifdef _KERNEL
+#define	SIMD_STAT_PRINT(s, feat, val) \
+	kmem_scnprintf(s + off, MAX(4095-off, 0), "%-16s\t%1d\n", feat, (val))
+
+static int
+simd_stat_kstat_data(char *buf, size_t size, void *data)
+{
+	(void) data;
+
+	static char simd_stat_kstat_payload[4096] = {0};
+	static int off = 0;
+#ifdef __linux__
+	if (off == 0) {
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "kfpu_allowed", kfpu_allowed());
+#ifdef __x86__
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "kfpu", HAVE_KERNEL_FPU);
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "kfpu_internal", HAVE_KERNEL_FPU_INTERNAL);
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "__kernel_fpu", HAVE_UNDERSCORE_KERNEL_FPU);
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sse", zfs_sse_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sse2", zfs_sse2_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sse3", zfs_sse3_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "ssse3", zfs_ssse3_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sse41", zfs_sse4_1_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sse42", zfs_sse4_2_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx", zfs_avx_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx2", zfs_avx2_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512f", zfs_avx512f_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512cd", zfs_avx512cd_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512er", zfs_avx512er_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512pf", zfs_avx512pf_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512bw", zfs_avx512bw_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512dq", zfs_avx512dq_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512vl", zfs_avx512vl_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512ifma", zfs_avx512ifma_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "avx512vbmi", zfs_avx512vbmi_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "ymm", __ymm_enabled());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "zmm", __zmm_enabled());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "bmi1", zfs_bmi1_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "bmi2", zfs_bmi2_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "aes", zfs_aes_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "pclmulqdq", zfs_pclmulqdq_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "movbe", zfs_movbe_available());
+
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "osxsave", boot_cpu_has(X86_FEATURE_OSXSAVE));
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "xsaves", static_cpu_has(X86_FEATURE_XSAVES));
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "xsaveopt", static_cpu_has(X86_FEATURE_XSAVEOPT));
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "xsave", static_cpu_has(X86_FEATURE_XSAVE));
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "fxsr", static_cpu_has(X86_FEATURE_FXSR));
+#endif /* __x86__ */
+#if defined(__arm__) || defined(__aarch64__)
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "kernel_neon", HAVE_KERNEL_NEON);
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "kernel_mode_neon", CONFIG_KERNEL_MODE_NEON);
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "neon", zfs_neon_available());
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sha256", zfs_sha256_available());
+#if defined(__aarch64__)
+		/*
+		 * This technically can exist on 32b ARM but we don't
+		 * define hooks to check for it and I didn't want to
+		 * learn enough ARM ASM to add one.
+		 */
+		off += SIMD_STAT_PRINT(simd_stat_kstat_payload,
+		    "sha512", zfs_sha512_available());
+#endif /* __aarch64__ */
+#endif /* __arm__ */
+		/* We want to short-circuit this on unsupported platforms. */
+		off += 1;
+	}
+
+	kmem_scnprintf(buf, MIN(off, size), "%s", simd_stat_kstat_payload);
+#endif /* __linux__ */
+	return (0);
+}
+#endif /* _KERNEL */
+
+void
+simd_stat_init(void)
+{
+	static boolean_t simd_stat_initialized = B_FALSE;
+
+	if (!simd_stat_initialized) {
+#if defined(_KERNEL)
+		/* Install kstats for all implementations */
+		simd_stat_kstat = kstat_create("zfs", 0, "simd", "misc",
+		    KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
+
+
+		if (simd_stat_kstat != NULL) {
+			simd_stat_kstat->ks_data = (void*)(uintptr_t)1;
+			simd_stat_kstat->ks_ndata = 1;
+			simd_stat_kstat->ks_flags |= KSTAT_FLAG_NO_HEADERS;
+			kstat_set_raw_ops(simd_stat_kstat,
+			    NULL,
+			    simd_stat_kstat_data,
+			    NULL);
+			kstat_install(simd_stat_kstat);
+		}
+#endif /* _KERNEL */
+	}
+	/* Finish initialization */
+	simd_stat_initialized = B_TRUE;
+}
+
+void
+simd_stat_fini(void)
+{
+#if defined(_KERNEL)
+	if (simd_stat_kstat != NULL) {
+		kstat_delete(simd_stat_kstat);
+		simd_stat_kstat = NULL;
+	}
+#endif
+}
+
+#ifdef _KERNEL
+EXPORT_SYMBOL(simd_stat_init);
+EXPORT_SYMBOL(simd_stat_fini);
+#endif

module/zcommon/zfs_prop.c

@@ -41,6 +41,7 @@
 #include <sys/zfs_ioctl.h>
 #include <sys/zfs_znode.h>
 #include <sys/dsl_crypt.h>
+#include <sys/simd.h>
 
 #include "zfs_prop.h"
 #include "zfs_deleg.h"
@@ -1063,6 +1064,9 @@ EXPORT_SYMBOL(zfs_kfpu_fpregs);
 extern int __init zcommon_init(void);
 extern void zcommon_fini(void);
 
+extern void simd_stat_init(void);
+extern void simd_stat_fini(void);
+
 int __init
 zcommon_init(void)
 {
@@ -1071,13 +1075,15 @@ zcommon_init(void)
 		return (error);
 
 	fletcher_4_init();
+	simd_stat_init();
 
 	return (0);
 }
 
 void
 zcommon_fini(void)
 {
+	simd_stat_fini();
 	fletcher_4_fini();
 	kfpu_fini();
 }