ia64/pv_ops/xen: elf note based xen startup.

This patch enables elf note based xen startup for IA-64, which gives the
kernel an early hint for running on xen like x86 case.
In order to avoid the multi entry point, presumably extending booting
protocol(i.e. extending struct ia64_boot_param) would be necessary.
It probably means that elilo also needs modification.

Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/xen/xensetup.S b/arch/ia64/xen/xensetup.S
new file mode 100644
index 0000000..28fed1f
--- /dev/null
+++ b/arch/ia64/xen/xensetup.S
@@ -0,0 +1,83 @@
+/*
+ * Support routines for Xen
+ *
+ * Copyright (C) 2005 Dan Magenheimer <dan.magenheimer@hp.com>
+ */
+
+#include <asm/processor.h>
+#include <asm/asmmacro.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/paravirt.h>
+#include <asm/xen/privop.h>
+#include <linux/elfnote.h>
+#include <linux/init.h>
+#include <xen/interface/elfnote.h>
+
+	.section .data.read_mostly
+	.align 8
+	.global xen_domain_type
+xen_domain_type:
+	data4 XEN_NATIVE_ASM
+	.previous
+
+	__INIT
+ENTRY(startup_xen)
+	// Calculate load offset.
+	// The constant, LOAD_OFFSET, can't be used because the boot
+	// loader doesn't always load to the LMA specified by the vmlinux.lds.
+	mov r9=ip	// must be the first instruction to make sure
+			// that r9 = the physical address of startup_xen.
+			// Usually r9 = startup_xen - LOAD_OFFSET
+	movl r8=startup_xen
+	;;
+	sub r9=r9,r8	// Usually r9 = -LOAD_OFFSET.
+
+	mov r10=PARAVIRT_HYPERVISOR_TYPE_XEN
+	movl r11=_start
+	;;
+	add r11=r11,r9
+	movl r8=hypervisor_type
+	;;
+	add r8=r8,r9
+	mov b0=r11
+	;;
+	st8 [r8]=r10
+	br.cond.sptk.many b0
+	;;
+END(startup_xen)
+
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,	.asciz "linux")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,	.asciz "2.6")
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,	.asciz "xen-3.0")
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,		data8.ua startup_xen - LOAD_OFFSET)
+
+#define isBP	p3	// are we the Bootstrap Processor?
+
+	.text
+
+GLOBAL_ENTRY(xen_setup_hook)
+	mov r8=XEN_PV_DOMAIN_ASM
+(isBP)	movl r9=xen_domain_type;;
+(isBP)	st4 [r9]=r8
+	movl r10=xen_ivt;;
+
+	mov cr.iva=r10
+
+	/* Set xsi base.  */
+#define FW_HYPERCALL_SET_SHARED_INFO_VA			0x600
+(isBP)	mov r2=FW_HYPERCALL_SET_SHARED_INFO_VA
+(isBP)	movl r28=XSI_BASE;;
+(isBP)	break 0x1000;;
+
+	/* setup pv_ops */
+(isBP)	mov r4=rp
+	;;
+(isBP)	br.call.sptk.many rp=xen_setup_pv_ops
+	;;
+(isBP)	mov rp=r4
+	;;
+
+	br.ret.sptk.many rp
+	;;
+END(xen_setup_hook)