Add BASIC i386 binary support for the amd64 kernel. This is largely

stolen from the ia64/ia32 code (indeed there was a repocopy), but I've
redone the MD parts and added and fixed a few essential syscalls.  It
is sufficient to run i386 binaries like /bin/ls, /usr/bin/id (dynamic)
and p4.  The ia64 code has not implemented signal delivery, so I had
to do that.

Before you say it, yes, this does need to go in a common place.  But
we're in a freeze at the moment and I didn't want to risk breaking ia64.
I will sort this out after the freeze so that the common code is in a
common place.

On the AMD64 side, this required adding segment selector context switch
support and some other support infrastructure.  The %fs/%gs etc code
is hairy because loading %gs will clobber the kernel's current MSR_GSBASE
setting.  The segment selectors are not used by the kernel, so they're only
changed at context switch time or when changing modes.  This still needs
to be optimized.

Approved by:	re (amd64/* blanket)

1 files changed, 87 insertions, 0 deletions

diff --git a/sys/amd64/ia32/ia32_sigtramp.S b/sys/amd64/ia32/ia32_sigtramp.S
new file mode 100644
index 0000000..2e9f73d
--- /dev/null
+++ b/sys/amd64/ia32/ia32_sigtramp.S
@@ -0,0 +1,87 @@
+/*-
+ * Copyright (c) 2003 Peter Wemm
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#include "opt_compat.h"
+
+#include <machine/asmacros.h>
+#include <sys/syscall.h>
+
+#include "ia32_assym.h"
+
+	.text
+	.code32
+/*
+ * Signal trampoline, copied to top of user stack
+ */
+	ALIGN_TEXT
+	.globl	ia32_sigcode
+ia32_sigcode:
+	calll	*IA32_SIGF_HANDLER(%esp)
+	leal	IA32_SIGF_UC(%esp),%eax	/* get ucontext */
+	pushl	%eax
+	movl	IA32_UC_GS(%eax),%gs	/* restore %gs */
+	movl	IA32_UC_FS(%eax),%fs	/* restore %fs */
+	movl	IA32_UC_ES(%eax),%es	/* restore %es */
+	movl	IA32_UC_DS(%eax),%ds	/* restore %ds */
+	movl	$SYS_sigreturn,%eax
+	pushl	%eax			/* junk to fake return addr. */
+	int	$0x80			/* enter kernel with args */
+					/* on stack */
+1:
+	jmp	1b
+
+#ifdef COMPAT_FREEBSD4
+	ALIGN_TEXT
+freebsd4_ia32_sigcode:
+	calll	*IA32_SIGF_HANDLER(%esp)
+	leal	IA32_SIGF_UC4(%esp),%eax/* get ucontext */
+	pushl	%eax
+	movl	IA32_UC4_GS(%eax),%gs	/* restore %gs */
+	movl	IA32_UC4_FS(%eax),%fs	/* restore %fs */
+	movl	IA32_UC4_ES(%eax),%es	/* restore %es */
+	movl	IA32_UC4_DS(%eax),%ds	/* restore %ds */
+	movl	$344,%eax		/* 4.x SYS_sigreturn */
+	pushl	%eax			/* junk to fake return addr. */
+	int	$0x80			/* enter kernel with args */
+					/* on stack */
+1:
+	jmp	1b
+#endif
+
+	ALIGN_TEXT
+esigcode:
+
+	.data
+	.globl	sz_ia32_sigcode
+sz_ia32_sigcode:
+	.long	esigcode-ia32_sigcode
+#ifdef COMPAT_FREEBSD4
+	.globl	sz_freebsd4_ia32_sigcode
+sz_freebsd4_ia32_sigcode:
+	.long	esigcode-freebsd4_ia32_sigcode
+#endif