svn commit: r289039 - in head/sys: arm64/conf conf

[Konstantin Belousov]

Author: kib
Date: Thu Oct  8 17:42:08 2015
New Revision: 289039
URL: https://svnweb.freebsd.org/changeset/base/289039

Log:
  Build changes that allow the modules on arm64.
  - Move the required kernel compiler flags from Makefile.arm64 to kern.mk.
  - Build arm64 modules as PIC; non-PIC relocations in .o for shared object
    output cannot be handled.
  - Do not try to install aarch64 symlink.
  - A hack for arm64 to avoid ld -r stage.  See the comment for the explanation.
    Some functionality is lost, like ctf handling, but hopefully will be
    restored after newer linker is available.
  
  Reviewed by:	andrew, emaste
  Tested by:	andrew (on real hardware)
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D3796

Modified:
  head/sys/arm64/conf/GENERIC
  head/sys/conf/Makefile.arm64
  head/sys/conf/kern.mk
  head/sys/conf/kern.post.mk
  head/sys/conf/kmod.mk

Modified: head/sys/arm64/conf/GENERIC
==============================================================================
--- head/sys/arm64/conf/GENERIC	Thu Oct  8 17:41:17 2015	(r289038)
+++ head/sys/arm64/conf/GENERIC	Thu Oct  8 17:42:08 2015	(r289039)
@@ -22,7 +22,6 @@ cpu		ARM64
 ident		GENERIC
 
 makeoptions	DEBUG=-g		# Build kernel with gdb(1) debug symbols
-makeoptions	NO_MODULES=1		# We don't yet support modules on arm64
 
 options 	SCHED_ULE		# ULE scheduler
 options 	PREEMPTION		# Enable kernel thread preemption

Modified: head/sys/conf/Makefile.arm64
==============================================================================
--- head/sys/conf/Makefile.arm64	Thu Oct  8 17:41:17 2015	(r289038)
+++ head/sys/conf/Makefile.arm64	Thu Oct  8 17:42:08 2015	(r289039)
@@ -27,12 +27,6 @@ S=	../../..
 
 INCLUDES+= -I$S/contrib/libfdt
 
-# We generally don't want fpu instructions in the kernel.
-CFLAGS += -mgeneral-regs-only
-
-# Reserve x18 for pcpu data
-CFLAGS += -ffixed-x18
-
 .if !empty(DDB_ENABLED)
 CFLAGS += -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer
 .endif

Modified: head/sys/conf/kern.mk
==============================================================================
--- head/sys/conf/kern.mk	Thu Oct  8 17:41:17 2015	(r289038)
+++ head/sys/conf/kern.mk	Thu Oct  8 17:42:08 2015	(r289039)
@@ -97,6 +97,13 @@ INLINE_LIMIT?=	8000
 INLINE_LIMIT?=	8000
 .endif
 
+.if ${MACHINE_CPUARCH} == "aarch64"
+# We generally don't want fpu instructions in the kernel.
+CFLAGS += -mgeneral-regs-only
+# Reserve x18 for pcpu data
+CFLAGS += -ffixed-x18
+.endif
+
 #
 # For sparc64 we want the medany code model so modules may be located
 # anywhere in the 64-bit address space.  We also tell GCC to use floating

Modified: head/sys/conf/kern.post.mk
==============================================================================
--- head/sys/conf/kern.post.mk	Thu Oct  8 17:41:17 2015	(r289038)
+++ head/sys/conf/kern.post.mk	Thu Oct  8 17:42:08 2015	(r289039)
@@ -212,7 +212,7 @@ SRCS=	assym.s vnode_if.h ${BEFORE_DEPEND
 	mv .newdep .depend
 
 _ILINKS= machine
-.if ${MACHINE} != ${MACHINE_CPUARCH}
+.if ${MACHINE} != ${MACHINE_CPUARCH} && ${MACHINE} != "arm64"
 _ILINKS+= ${MACHINE_CPUARCH}
 .endif
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"

Modified: head/sys/conf/kmod.mk
==============================================================================
--- head/sys/conf/kmod.mk	Thu Oct  8 17:41:17 2015	(r289038)
+++ head/sys/conf/kmod.mk	Thu Oct  8 17:42:08 2015	(r289039)
@@ -113,6 +113,10 @@ CFLAGS+=	${DEBUG_FLAGS}
 CFLAGS+=	-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer
 .endif
 
+.if ${MACHINE_CPUARCH} == "aarch64"
+CFLAGS+=	-fPIC
+.endif
+
 # Temporary workaround for PR 196407, which contains the fascinating details.
 # Don't allow clang to use fpu instructions or registers in kernel modules.
 .if ${MACHINE_CPUARCH} == arm
@@ -182,7 +186,17 @@ ${PROG}.debug: ${FULLPROG}
 
 .if ${__KLD_SHARED} == yes
 ${FULLPROG}: ${KMOD}.kld
+.if ${MACHINE_CPUARCH} != "aarch64"
 	${LD} -Bshareable ${_LDFLAGS} -o ${.TARGET} ${KMOD}.kld
+.else
+#XXXKIB Relocatable linking in aarch64 ld from binutils 2.25.1 does
+#       not work.  The linker corrupts the references to the external
+#       symbols which are defined by other object in the linking set
+#       and should therefore loose the GOT entry.  The problem seems
+#       to be fixed in the binutils-gdb git HEAD as of 2015-10-04.  Hack
+#       below allows to get partially functioning modules for now.
+	${LD} -Bshareable ${_LDFLAGS} -o ${.TARGET} ${OBJS}
+.endif
 .if !defined(DEBUG_FLAGS)
 	${OBJCOPY} --strip-debug ${.TARGET}
 .endif
@@ -220,7 +234,7 @@ ${FULLPROG}: ${OBJS}
 .endif
 
 _ILINKS=machine
-.if ${MACHINE} != ${MACHINE_CPUARCH}
+.if ${MACHINE} != ${MACHINE_CPUARCH} && ${MACHINE} != "arm64"
 _ILINKS+=${MACHINE_CPUARCH}
 .endif
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"