Provide the CloudABI vDSO to its executables.

CloudABI executables already provide support for passing in vDSOs. This
functionality is used by the emulator for OS X to inject system call
handlers. On FreeBSD, we could use it to optimize calls to
gettimeofday(), etc.

Though I don't have any plans to optimize any system calls right now,
let's go ahead and already pass in a vDSO. This will allow us to
simplify the executables, as the traditional "syscall" shims can be
removed entirely. It also means that we gain more flexibility with
regards to adding and removing system calls.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D7438

11 files changed, 211 insertions, 5 deletions

diff --git a/sys/amd64/cloudabi64/cloudabi64_sysvec.c b/sys/amd64/cloudabi64/cloudabi64_sysvec.c
index 08d85a2d5cb7..cefdef983238 100644
--- a/sys/amd64/cloudabi64/cloudabi64_sysvec.c
+++ b/sys/amd64/cloudabi64/cloudabi64_sysvec.c
@@ -196,7 +196,6 @@ static struct sysentvec cloudabi64_elf_sysvec = {
 	.sv_pagesize		= PAGE_SIZE,
 	.sv_minuser		= VM_MIN_ADDRESS,
 	.sv_maxuser		= VM_MAXUSER_ADDRESS,
-	.sv_usrstack		= USRSTACK,
 	.sv_stackprot		= VM_PROT_READ | VM_PROT_WRITE,
 	.sv_copyout_strings	= cloudabi64_copyout_strings,
 	.sv_setregs		= cloudabi64_proc_setregs,
diff --git a/sys/arm64/cloudabi64/cloudabi64_sysvec.c b/sys/arm64/cloudabi64/cloudabi64_sysvec.c
index cf3e594244bb..ebcb54e1a867 100644
--- a/sys/arm64/cloudabi64/cloudabi64_sysvec.c
+++ b/sys/arm64/cloudabi64/cloudabi64_sysvec.c
@@ -165,7 +165,6 @@ static struct sysentvec cloudabi64_elf_sysvec = {
 	.sv_pagesize		= PAGE_SIZE,
 	.sv_minuser		= VM_MIN_ADDRESS,
 	.sv_maxuser		= VM_MAXUSER_ADDRESS,
-	.sv_usrstack		= USRSTACK,
 	.sv_stackprot		= VM_PROT_READ | VM_PROT_WRITE,
 	.sv_copyout_strings	= cloudabi64_copyout_strings,
 	.sv_setregs		= cloudabi64_proc_setregs,
diff --git a/sys/compat/cloudabi/cloudabi_util.h b/sys/compat/cloudabi/cloudabi_util.h
index c0a02aa88dcb..6eb65aa87b32 100644
--- a/sys/compat/cloudabi/cloudabi_util.h
+++ b/sys/compat/cloudabi/cloudabi_util.h
@@ -33,6 +33,7 @@
 #include <contrib/cloudabi/cloudabi_types_common.h>
 
 struct file;
+struct sysentvec;
 struct thread;
 struct timespec;
 
@@ -76,4 +77,8 @@ int cloudabi_futex_lock_wrlock(struct thread *, cloudabi_lock_t *,
     cloudabi_scope_t, cloudabi_clockid_t, cloudabi_timestamp_t,
     cloudabi_timestamp_t);
 
+/* vDSO setup and teardown. */
+void cloudabi_vdso_init(struct sysentvec *, char *, char *);
+void cloudabi_vdso_destroy(struct sysentvec *);
+
 #endif
diff --git a/sys/compat/cloudabi/cloudabi_vdso.c b/sys/compat/cloudabi/cloudabi_vdso.c
new file mode 100644
index 000000000000..27c3d365af83
--- /dev/null
+++ b/sys/compat/cloudabi/cloudabi_vdso.c
@@ -0,0 +1,88 @@
+/*-
+ * Copyright (c) 2016 Nuxi, https://nuxi.nl/
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/lock.h>
+#include <sys/sysent.h>
+#include <sys/rwlock.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_extern.h>
+#include <vm/vm_object.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pager.h>
+
+#include <compat/cloudabi/cloudabi_util.h>
+
+void
+cloudabi_vdso_init(struct sysentvec *sv, char *begin, char *end)
+{
+	vm_page_t m;
+	vm_object_t obj;
+	vm_offset_t addr;
+	size_t i, pages, pages_length, vdso_length;
+
+	/* Determine the number of pages needed to store the vDSO. */
+	vdso_length = end - begin;
+	pages = howmany(vdso_length, PAGE_SIZE);
+	pages_length = pages * PAGE_SIZE;
+
+	/* Allocate a VM object and fill it with the vDSO. */
+	obj = vm_pager_allocate(OBJT_PHYS, 0, pages_length,
+	    VM_PROT_DEFAULT, 0, NULL);
+	addr = kva_alloc(PAGE_SIZE);
+	for (i = 0; i < pages; ++i) {
+		VM_OBJECT_WLOCK(obj);
+		m = vm_page_grab(obj, i, VM_ALLOC_NOBUSY | VM_ALLOC_ZERO);
+		m->valid = VM_PAGE_BITS_ALL;
+		VM_OBJECT_WUNLOCK(obj);
+
+		pmap_qenter(addr, &m, 1);
+		memcpy((void *)addr, begin + i * PAGE_SIZE,
+		    MIN(vdso_length - i * PAGE_SIZE, PAGE_SIZE));
+		pmap_qremove(addr, 1);
+	}
+	kva_free(addr, PAGE_SIZE);
+
+	/*
+	 * Place the vDSO at the top of the address space. The user
+	 * stack can start right below it.
+	 */
+	sv->sv_shared_page_base = sv->sv_maxuser - pages_length;
+	sv->sv_shared_page_len = pages_length;
+	sv->sv_shared_page_obj = obj;
+	sv->sv_usrstack = sv->sv_shared_page_base;
+}
+
+void
+cloudabi_vdso_destroy(struct sysentvec *sv)
+{
+
+	vm_object_deallocate(sv->sv_shared_page_obj);
+}
diff --git a/sys/compat/cloudabi64/cloudabi64_module.c b/sys/compat/cloudabi64/cloudabi64_module.c
index 246a887105cb..da1ea1149a4b 100644
--- a/sys/compat/cloudabi64/cloudabi64_module.c
+++ b/sys/compat/cloudabi64/cloudabi64_module.c
@@ -38,8 +38,13 @@ __FBSDID("$FreeBSD$");
 
 #include <contrib/cloudabi/cloudabi64_types.h>
 
+#include <compat/cloudabi/cloudabi_util.h>
+
 #include <compat/cloudabi64/cloudabi64_util.h>
 
+extern char _binary_cloudabi64_vdso_o_start[];
+extern char _binary_cloudabi64_vdso_o_end[];
+
 register_t *
 cloudabi64_copyout_strings(struct image_params *imgp)
 {
@@ -107,6 +112,8 @@ cloudabi64_fixup(register_t **stack_base, struct image_params *imgp)
 		PTR(CLOUDABI_AT_PHDR, args->phdr),
 		VAL(CLOUDABI_AT_PHNUM, args->phnum),
 		VAL(CLOUDABI_AT_TID, td->td_tid),
+		PTR(CLOUDABI_AT_SYSINFO_EHDR,
+		    imgp->proc->p_sysent->sv_shared_page_base),
 #undef VAL
 #undef PTR
 		{ .a_type = CLOUDABI_AT_NULL },
@@ -127,6 +134,9 @@ cloudabi64_modevent(module_t mod, int type, void *data)
 
 	switch (type) {
 	case MOD_LOAD:
+		cloudabi_vdso_init(cloudabi64_brand.sysvec,
+		    _binary_cloudabi64_vdso_o_start,
+		    _binary_cloudabi64_vdso_o_end);
 		if (elf64_insert_brand_entry(&cloudabi64_brand) < 0) {
 			printf("Failed to add CloudABI ELF brand handler\n");
 			return (EINVAL);
@@ -139,6 +149,7 @@ cloudabi64_modevent(module_t mod, int type, void *data)
 			printf("Failed to remove CloudABI ELF brand handler\n");
 			return (EINVAL);
 		}
+		cloudabi_vdso_destroy(cloudabi64_brand.sysvec);
 		return (0);
 	default:
 		return (EOPNOTSUPP);
diff --git a/sys/compat/cloudabi64/cloudabi64_vdso.lds.s b/sys/compat/cloudabi64/cloudabi64_vdso.lds.s
new file mode 100644
index 000000000000..29c94d3cdde8
--- /dev/null
+++ b/sys/compat/cloudabi64/cloudabi64_vdso.lds.s
@@ -0,0 +1,51 @@
+/*
+ * Linker script for 64-bit vDSO for CloudABI.
+ * Based on sys/amd64/linux/linux_vdso.lds.s
+ *
+ * $FreeBSD$
+ */
+
+SECTIONS
+{
+	. = . + SIZEOF_HEADERS;
+
+	.hash		: { *(.hash) }			:text
+	.gnu.hash	: { *(.gnu.hash) }
+	.dynsym		: { *(.dynsym) }
+	.dynstr		: { *(.dynstr) }
+	.gnu.version	: { *(.gnu.version) }
+	.gnu.version_d	: { *(.gnu.version_d) }
+	.gnu.version_r	: { *(.gnu.version_r) }
+
+	.note		: { *(.note.*) }		:text	:note
+
+	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
+	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
+
+	.dynamic	: { *(.dynamic) }		:text	:dynamic
+
+	.rodata		: { *(.rodata*) }		:text
+	.data		: {
+	      *(.data*)
+	      *(.sdata*)
+	      *(.got.plt) *(.got)
+	      *(.gnu.linkonce.d.*)
+	      *(.bss*)
+	      *(.dynbss*)
+	      *(.gnu.linkonce.b.*)
+	}
+
+	.altinstructions	: { *(.altinstructions) }
+	.altinstr_replacement	: { *(.altinstr_replacement) }
+
+	. = ALIGN(0x100);
+	.text		: { *(.test .text*) }			:text	=0x90909090
+}
+
+PHDRS
+{
+	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
+	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
+	note		PT_NOTE		FLAGS(4);		/* PF_R */
+	eh_frame_hdr	PT_GNU_EH_FRAME;
+}
diff --git a/sys/conf/files b/sys/conf/files
index 4f5fa71ee9b8..993f0c3892ab 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -284,6 +284,7 @@ compat/cloudabi/cloudabi_proc.c		optional compat_cloudabi64
 compat/cloudabi/cloudabi_random.c	optional compat_cloudabi64
 compat/cloudabi/cloudabi_sock.c		optional compat_cloudabi64
 compat/cloudabi/cloudabi_thread.c	optional compat_cloudabi64
+compat/cloudabi/cloudabi_vdso.c		optional compat_cloudabi64
 compat/cloudabi64/cloudabi64_fd.c	optional compat_cloudabi64
 compat/cloudabi64/cloudabi64_module.c	optional compat_cloudabi64
 compat/cloudabi64/cloudabi64_poll.c	optional compat_cloudabi64
diff --git a/sys/conf/files.amd64 b/sys/conf/files.amd64
index 331b811081f7..df5d1bcfb88e 100644
--- a/sys/conf/files.amd64
+++ b/sys/conf/files.amd64
@@ -8,6 +8,18 @@
 # dependency lines other than the first are silently ignored.
 #
 #
+cloudabi64_vdso.o		optional	compat_cloudabi64	\
+	dependency	"$S/contrib/cloudabi/cloudabi_vdso_x86_64.c"	\
+	compile-with	"${CC} -shared -nostdinc -nostdlib -Wl,-T$S/compat/cloudabi64/cloudabi64_vdso.lds.s -D_KERNEL -I. -I$S -I$S/contrib/cloudabi -O2 -fomit-frame-pointer $S/contrib/cloudabi/cloudabi_vdso_x86_64.c -o ${.TARGET}" \
+	no-obj no-implicit-rule						\
+	clean		"cloudabi64_vdso.o"
+#
+cloudabi64_vdso_blob.o		optional	compat_cloudabi64	\
+	dependency 	"cloudabi64_vdso.o"				\
+	compile-with	"${OBJCOPY} --input-target binary --output-target elf64-x86-64-freebsd --binary-architecture i386 cloudabi64_vdso.o ${.TARGET}" \
+	no-implicit-rule						\
+	clean		"cloudabi64_vdso_blob.o"
+#
 linux32_genassym.o		optional	compat_linux32		\
 	dependency 	"$S/amd64/linux32/linux32_genassym.c"		\
 	compile-with	"${CC} ${CFLAGS:N-fno-common} -c ${.IMPSRC}"	\
diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
index b4c82085ace0..31acaf9ce32f 100644
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -1,4 +1,16 @@
 # $FreeBSD$
+cloudabi64_vdso.o		optional	compat_cloudabi64	\
+	dependency	"$S/contrib/cloudabi/cloudabi_vdso_aarch64.c"	\
+	compile-with	"${CC} -shared -nostdinc -nostdlib -Wl,-T$S/compat/cloudabi64/cloudabi64_vdso.lds.s -D_KERNEL -I. -I$S -I$S/contrib/cloudabi -O2 -fomit-frame-pointer $S/contrib/cloudabi/cloudabi_vdso_aarch64.c -o ${.TARGET}" \
+	no-obj no-implicit-rule						\
+	clean		"cloudabi64_vdso.o"
+#
+cloudabi64_vdso_blob.o		optional	compat_cloudabi64	\
+	dependency 	"cloudabi64_vdso.o"			\
+	compile-with	"${OBJCOPY} --input-target binary --output-target elf64-littleaarch64 --binary-architecture aarch64 cloudabi64_vdso.o ${.TARGET}" \
+	no-implicit-rule						\
+	clean		"cloudabi64_vdso_blob.o"
+#
 arm/arm/generic_timer.c		standard
 arm/arm/gic.c			standard
 arm/arm/gic_fdt.c		optional	fdt
diff --git a/sys/modules/cloudabi/Makefile b/sys/modules/cloudabi/Makefile
index bba50362eab1..c608580c7f30 100644
--- a/sys/modules/cloudabi/Makefile
+++ b/sys/modules/cloudabi/Makefile
@@ -5,6 +5,6 @@
 KMOD=	cloudabi
 SRCS=	cloudabi_clock.c cloudabi_errno.c cloudabi_fd.c cloudabi_file.c \
 	cloudabi_futex.c cloudabi_mem.c cloudabi_proc.c cloudabi_random.c \
-	cloudabi_sock.c cloudabi_thread.c vnode_if.h
+	cloudabi_sock.c cloudabi_thread.c cloudabi_vdso.c vnode_if.h
 
 .include <bsd.kmod.mk>
diff --git a/sys/modules/cloudabi64/Makefile b/sys/modules/cloudabi64/Makefile
index 3aee96d97525..b6fe38057ba8 100644
--- a/sys/modules/cloudabi64/Makefile
+++ b/sys/modules/cloudabi64/Makefile
@@ -1,11 +1,39 @@
 # $FreeBSD$
 
-.PATH: ${.CURDIR}/../../compat/cloudabi64
-.PATH: ${.CURDIR}/../../${MACHINE}/cloudabi64
+SYSDIR?=${.CURDIR}/../..
+
+.PATH: ${SYSDIR}/compat/cloudabi64
+.PATH: ${SYSDIR}/${MACHINE}/cloudabi64
 
 KMOD=	cloudabi64
 SRCS=	cloudabi64_fd.c cloudabi64_module.c cloudabi64_poll.c \
 	cloudabi64_sock.c cloudabi64_syscalls.c cloudabi64_sysent.c \
 	cloudabi64_sysvec.c cloudabi64_thread.c
 
+OBJS=	cloudabi64_vdso_blob.o
+CLEANFILES=cloudabi64_vdso.o
+
+.if ${MACHINE_CPUARCH} == "aarch64"
+VDSO_SRCS=${SYSDIR}/contrib/cloudabi/cloudabi_vdso_aarch64.c
+OUTPUT_TARGET=elf64-littleaarch64
+BINARY_ARCHITECTURE=aarch64
+.elif ${MACHINE_CPUARCH} == "amd64"
+VDSO_SRCS=${SYSDIR}/contrib/cloudabi/cloudabi_vdso_x86_64.c
+OUTPUT_TARGET=elf64-x86-64-freebsd
+BINARY_ARCHITECTURE=i386
+.endif
+
+cloudabi64_vdso.o: ${VDSO_SRCS}
+	${CC} -shared -nostdinc -nostdlib \
+	    -Wl,-T${SYSDIR}/compat/cloudabi64/cloudabi64_vdso.lds.s \
+	    -D_KERNEL -I. -I${SYSDIR} -I${SYSDIR}/contrib/cloudabi \
+	    -O2 -fomit-frame-pointer \
+	    ${VDSO_SRCS} -o ${.TARGET}
+
+cloudabi64_vdso_blob.o: cloudabi64_vdso.o
+	${OBJCOPY} --input-target binary \
+	    --output-target ${OUTPUT_TARGET} \
+	    --binary-architecture ${BINARY_ARCHITECTURE} \
+	    cloudabi64_vdso.o ${.TARGET}
+
 .include <bsd.kmod.mk>