OpenZFS restructuring - move platform specific headers

Move platform specific Linux headers under include/os/linux/.
Update the build system accordingly to detect the platform.
This lays some of the initial groundwork to supporting building
for other platforms.

As part of this change it was necessary to create both a user
and kernel space sys/simd.h header which can be included in
either context.  No functional change, the source has been
refactored and the relevant #include's updated.

Reviewed-by: Jorgen Lundman <[email protected]>
Reviewed-by: Igor Kozhukhov <[email protected]>
Signed-off-by: Matthew Macy <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes openzfs#9198

config/always-system.m4

@@ -0,0 +1,26 @@
+dnl #
+dnl # Set the target system
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_SYSTEM], [
+	AC_MSG_CHECKING([for system type ($host_os)])
+	case $host_os in
+		*linux*)
+			AC_DEFINE([SYSTEM_LINUX], [1],
+				[True if ZFS is to be compiled for a Linux system])
+			ac_system="Linux"
+			;;
+		*freebsd*)
+			AC_DEFINE([SYSTEM_FREEBSD], [1],
+				[True if ZFS is to be compiled for a FreeBSD system])
+			ac_system="FreeBSD"
+			;;
+		*)
+			ac_system="unknown"
+			;;
+	esac
+	AC_MSG_RESULT([$ac_system])
+	AC_SUBST([ac_system])
+
+	AM_CONDITIONAL([BUILD_LINUX], [test "x$ac_system" = "xLinux"])
+	AM_CONDITIONAL([BUILD_FREEBSD], [test "x$ac_system" = "xFreeBSD"])
+])

config/zfs-build.m4

@@ -160,6 +160,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
 	ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER
 	ZFS_AC_CONFIG_ALWAYS_CC_ASAN
 	ZFS_AC_CONFIG_ALWAYS_TOOLCHAIN_SIMD
+	ZFS_AC_CONFIG_ALWAYS_SYSTEM
 	ZFS_AC_CONFIG_ALWAYS_ARCH
 	ZFS_AC_CONFIG_ALWAYS_PYTHON
 	ZFS_AC_CONFIG_ALWAYS_PYZFS

configure.ac

@@ -146,10 +146,15 @@ AC_CONFIG_FILES([
 	module/icp/Makefile
 	module/spl/Makefile
 	include/Makefile
-	include/linux/Makefile
-	include/spl/Makefile
-	include/spl/rpc/Makefile
-	include/spl/sys/Makefile
+	include/os/Makefile
+	include/os/linux/Makefile
+	include/os/linux/kernel/Makefile
+	include/os/linux/kernel/linux/Makefile
+	include/os/linux/spl/Makefile
+	include/os/linux/spl/rpc/Makefile
+	include/os/linux/spl/sys/Makefile
+	include/os/linux/zfs/Makefile
+	include/os/linux/zfs/sys/Makefile
 	include/sys/Makefile
 	include/sys/fs/Makefile
 	include/sys/fm/Makefile

copy-builtin

@@ -62,7 +62,9 @@ EOF
 {
 	cat <<-"EOF"
 	ZFS_MODULE_CFLAGS  = -I$(srctree)/include/zfs
-	ZFS_MODULE_CFLAGS += -I$(srctree)/include/zfs/spl
+	ZFS_MODULE_CFLAGS += -I$(srctree)/include/zfs/os/linux/spl
+	ZFS_MODULE_CFLAGS += -I$(srctree)/include/zfs/os/linux/zfs
+	ZFS_MODULE_CFLAGS += -I$(srctree)/include/zfs/os/linux/kernel
 	ZFS_MODULE_CFLAGS += -include $(srctree)/include/zfs/zfs_config.h
 	ZFS_MODULE_CFLAGS += -std=gnu99 -Wno-declaration-after-statement
 	ZFS_MODULE_CPPFLAGS  = -D_KERNEL

include/.gitignore

@@ -1 +1,2 @@
 /zfs_gitrev.h
+/spl

include/Makefile.am

@@ -1,4 +1,4 @@
-SUBDIRS = linux spl sys
+SUBDIRS = sys os
 
 COMMON_H = \
 	$(top_srcdir)/include/zfeature_common.h \

include/os/Makefile.am

@@ -0,0 +1,3 @@
+if BUILD_LINUX
+SUBDIRS = linux
+endif

include/os/linux/Makefile.am

@@ -0,0 +1 @@
+SUBDIRS = kernel spl zfs

include/os/linux/kernel/Makefile.am

@@ -0,0 +1 @@
+SUBDIRS = linux

include/os/linux/kernel/linux/Makefile.am

@@ -0,0 +1,29 @@
+COMMON_H =
+
+KERNEL_H = \
+	$(top_srcdir)/include/os/linux/kernel/linux/dcache_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/xattr_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/vfs_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/blkdev_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/utsname_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/kmap_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/simd.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/simd_x86.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/simd_aarch64.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/mod_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/page_compat.h \
+	$(top_srcdir)/include/os/linux/kernel/linux/compiler_compat.h
+
+USER_H =
+
+EXTRA_DIST = $(COMMON_H) $(KERNEL_H) $(USER_H)
+
+if CONFIG_USER
+libzfsdir = $(includedir)/libzfs/linux
+libzfs_HEADERS = $(COMMON_H) $(USER_H)
+endif
+
+if CONFIG_KERNEL
+kerneldir = @prefix@/src/zfs-$(VERSION)/include/linux
+kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+endif

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

@@ -22,8 +22,8 @@
  * Copyright (C) 2019 Lawrence Livermore National Security, LLC.
  */
 
-#ifndef _SIMD_H
-#define	_SIMD_H
+#ifndef _LINUX_SIMD_H
+#define	_LINUX_SIMD_H
 
 #if defined(__x86)
 #include <linux/simd_x86.h>
@@ -32,10 +32,10 @@
 #include <linux/simd_aarch64.h>
 #else
 
-#define	kfpu_allowed()		1
+#define	kfpu_allowed()		0
 #define	kfpu_initialize(tsk)	do {} while (0)
 #define	kfpu_begin()		do {} while (0)
 #define	kfpu_end()		do {} while (0)
 
 #endif
-#endif /* _SIMD_H */
+#endif /* _LINUX_SIMD_H */

include/linux/simd_aarch64.h → include/os/linux/kernel/linux/simd_aarch64.h

@@ -32,31 +32,21 @@
  *	kfpu_end()
  */
 
-#ifndef _SIMD_AARCH64_H
-#define	_SIMD_AARCH64_H
+#ifndef _LINUX_SIMD_AARCH64_H
+#define	_LINUX_SIMD_AARCH64_H
 
 #include <sys/isa_defs.h>
 
 #if defined(__aarch64__)
 
 #include <sys/types.h>
-
-#if defined(_KERNEL)
 #include <asm/neon.h>
+
 #define	kfpu_allowed()		1
 #define	kfpu_initialize(tsk)	do {} while (0)
 #define	kfpu_begin()		kernel_neon_begin()
 #define	kfpu_end()		kernel_neon_end()
-#else
-/*
- * fpu dummy methods for userspace
- */
-#define	kfpu_allowed()		1
-#define	kfpu_initialize(tsk)	do {} while (0)
-#define	kfpu_begin()		do {} while (0)
-#define	kfpu_end()		do {} while (0)
-#endif /* defined(_KERNEL) */
 
 #endif /* __aarch64__ */
 
-#endif /* _SIMD_AARCH64_H */
+#endif /* _LINUX_SIMD_AARCH64_H */