MFC r303818, r303833, r303941, r304478, r304481, r304483, r304484, r304554,

    r304555, r304556, r304557, r304558, r304559, r304561, r304563, r304564,
    r304565, r304615, r304742, r304743, r304744, r304745, r304748, r304886,
    r304991, r305928, r305938, r305987, r306185:

  Bring CloudABI support back in sync with HEAD.

  - Add support for running 32-bit executables on amd64, armv6 and i386.

  - As these new architectures require the use of the vDSO, merge back
    vDSO support for 64-bit executables running on amd64 and arm64 as
    well. This has the advantage that support for vDSO-less execution
    can be phased out when 11.0 becomes unsupported, as opposed to 11.x.

  This change has been tested by running the cloudlibc unit tests on all
  supported architectures, which seems to work fine.

2 files changed, 207 insertions, 0 deletions

diff --git a/sys/i386/cloudabi32/cloudabi32_sysvec.c b/sys/i386/cloudabi32/cloudabi32_sysvec.c
new file mode 100644
index 0000000..1ecd8d5
--- /dev/null
+++ b/sys/i386/cloudabi32/cloudabi32_sysvec.c
@@ -0,0 +1,204 @@
+/*-
+ * Copyright (c) 2015-2016 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/param.h>
+#include <sys/imgact.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+#include <sys/sysent.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+
+#include <machine/frame.h>
+#include <machine/pcb.h>
+#include <machine/vmparam.h>
+
+#include <compat/cloudabi/cloudabi_util.h>
+
+#include <compat/cloudabi32/cloudabi32_syscall.h>
+#include <compat/cloudabi32/cloudabi32_util.h>
+
+extern const char *cloudabi32_syscallnames[];
+extern struct sysent cloudabi32_sysent[];
+
+static int
+cloudabi32_fixup_tcb(register_t **stack_base, struct image_params *imgp)
+{
+	int error;
+	uint32_t args[2];
+
+	/* Place auxiliary vector and TCB on the stack. */
+	error = cloudabi32_fixup(stack_base, imgp);
+	if (error != 0)
+		return (error);
+
+	/*
+	 * On i386, the TCB is referred to by %gs:0. Reuse the empty
+	 * space normally used by the return address (args[0]) to store
+	 * a single element array, containing a pointer to the TCB. %gs
+	 * base will point to this.
+	 *
+	 * Also let the first argument of the entry point (args[1])
+	 * refer to the auxiliary vector, which is stored right after
+	 * the TCB.
+	 */
+	args[0] = (uintptr_t)*stack_base;
+	args[1] = (uintptr_t)*stack_base +
+	    roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t));
+	*stack_base -= howmany(sizeof(args), sizeof(register_t));
+	return (copyout(args, *stack_base, sizeof(args)));
+}
+
+static void
+cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp,
+    unsigned long stack)
+{
+
+	exec_setregs(td, imgp, stack);
+	(void)cpu_set_user_tls(td, (void *)stack);
+}
+
+static int
+cloudabi32_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
+{
+	struct trapframe *frame = td->td_frame;
+	int error;
+
+	/* Obtain system call number. */
+	sa->code = frame->tf_eax;
+	if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL)
+		return (ENOSYS);
+	sa->callp = &cloudabi32_sysent[sa->code];
+	sa->narg = sa->callp->sy_narg;
+
+	/* Fetch system call arguments from the stack. */
+	error = copyin((void *)(frame->tf_esp + 4), sa->args,
+	    sa->narg * sizeof(sa->args[0]));
+	if (error != 0)
+		return (error);
+
+	/* Default system call return values. */
+	td->td_retval[0] = 0;
+	td->td_retval[1] = frame->tf_edx;
+	return (0);
+}
+
+static void
+cloudabi32_set_syscall_retval(struct thread *td, int error)
+{
+	struct trapframe *frame = td->td_frame;
+
+	switch (error) {
+	case 0:
+		/* System call succeeded. */
+		frame->tf_eax = td->td_retval[0];
+		frame->tf_edx = td->td_retval[1];
+		frame->tf_eflags &= ~PSL_C;
+		break;
+	case ERESTART:
+		/* Restart system call. */
+		frame->tf_eip -= frame->tf_err;
+		break;
+	case EJUSTRETURN:
+		break;
+	default:
+		/* System call returned an error. */
+		frame->tf_eax = cloudabi_convert_errno(error);
+		frame->tf_eflags |= PSL_C;
+		break;
+	}
+}
+
+static void
+cloudabi32_schedtail(struct thread *td)
+{
+	struct trapframe *frame = td->td_frame;
+
+	/* Initial register values for processes returning from fork. */
+	frame->tf_eax = CLOUDABI_PROCESS_CHILD;
+	frame->tf_edx = td->td_tid;
+}
+
+int
+cloudabi32_thread_setregs(struct thread *td,
+    const cloudabi32_threadattr_t *attr, uint32_t tcb)
+{
+	stack_t stack;
+	uint32_t args[3];
+	void *frameptr;
+	int error;
+
+	/* Perform standard register initialization. */
+	stack.ss_sp = TO_PTR(attr->stack);
+	stack.ss_size = attr->stack_size - sizeof(args);
+	cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack);
+
+	/*
+	 * Copy the arguments for the thread entry point onto the stack
+	 * (args[1] and args[2]). Similar to process startup, use the
+	 * otherwise unused return address (args[0]) for TLS.
+	 */
+	args[0] = tcb;
+	args[1] = td->td_tid;
+	args[2] = attr->argument;
+	frameptr = (void *)td->td_frame->tf_esp;
+	error = copyout(args, frameptr, sizeof(args));
+	if (error != 0)
+		return (error);
+
+	return (cpu_set_user_tls(td, frameptr));
+}
+
+static struct sysentvec cloudabi32_elf_sysvec = {
+	.sv_size		= CLOUDABI32_SYS_MAXSYSCALL,
+	.sv_table		= cloudabi32_sysent,
+	.sv_fixup		= cloudabi32_fixup_tcb,
+	.sv_name		= "CloudABI ELF32",
+	.sv_coredump		= elf32_coredump,
+	.sv_pagesize		= PAGE_SIZE,
+	.sv_minuser		= VM_MIN_ADDRESS,
+	.sv_maxuser		= VM_MAXUSER_ADDRESS,
+	.sv_stackprot		= VM_PROT_READ | VM_PROT_WRITE,
+	.sv_copyout_strings	= cloudabi32_copyout_strings,
+	.sv_setregs		= cloudabi32_proc_setregs,
+	.sv_flags		= SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32,
+	.sv_set_syscall_retval	= cloudabi32_set_syscall_retval,
+	.sv_fetch_syscall_args	= cloudabi32_fetch_syscall_args,
+	.sv_syscallnames	= cloudabi32_syscallnames,
+	.sv_schedtail		= cloudabi32_schedtail,
+};
+
+INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
+
+Elf32_Brandinfo cloudabi32_brand = {
+	.brand		= ELFOSABI_CLOUDABI,
+	.machine	= EM_386,
+	.sysvec		= &cloudabi32_elf_sysvec,
+	.compat_3_brand	= "CloudABI",
+};
diff --git a/sys/i386/conf/NOTES b/sys/i386/conf/NOTES
index 52bd6bf..e0065f8 100644
--- a/sys/i386/conf/NOTES
+++ b/sys/i386/conf/NOTES
@@ -989,6 +989,9 @@ options 	NKPT=31
 # Emulate spx device for client side of SVR3 local X interface
 options 	SPX_HACK
 
+# Enable 32-bit runtime support for CloudABI binaries.
+options 	COMPAT_CLOUDABI32
+
 # Enable Linux ABI emulation
 options 	COMPAT_LINUX