[Xen-ia64-devel] [PATCH 11/23] ia64/xen: detect xen environment and do minimal initialization.

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Add a hook for xen detection and initialization. It detects
xen environment and does minimal initialization.
For now xen is detected by checking psr.cpl != 0.
It's ok for now, but more abstraction would be needed later like x86.
Presumably extending booting protocol (i.e. extending struct ia64_boot_param)
or multi entry points depending on hypervisor would be necessary.

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
---
 arch/ia64/kernel/head.S    |    6 ++++
 arch/ia64/xen/Makefile     |    3 +-
 arch/ia64/xen/xen_pv_ops.c |   65 ++++++++++++++++++++++++++++++++++++++++++++
 arch/ia64/xen/xensetup.S   |   49 +++++++++++++++++++++++++++++++++
 4 files changed, 122 insertions(+), 1 deletions(-)
 create mode 100644 arch/ia64/xen/xen_pv_ops.c
 create mode 100644 arch/ia64/xen/xensetup.S

diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index ddeab4e..39fecfc 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -367,6 +367,12 @@ start_ap:
        ;;
 (isBP) st8 [r2]=r28            // save the address of the boot param area 
passed by the bootloader
 
+#ifdef CONFIG_XEN
+       //  Note: isBP is used by the subprogram.
+       br.call.sptk.many rp=early_xen_setup
+       ;;
+#endif
+
 #ifdef CONFIG_SMP
 (isAP) br.call.sptk.many rp=start_secondary
 .ret0:
diff --git a/arch/ia64/xen/Makefile b/arch/ia64/xen/Makefile
index eb59563..abc356f 100644
--- a/arch/ia64/xen/Makefile
+++ b/arch/ia64/xen/Makefile
@@ -2,4 +2,5 @@
 # Makefile for Xen components
 #
 
-obj-y := hypercall.o xencomm.o xcom_hcall.o grant-table.o
+obj-y := hypercall.o xensetup.o xen_pv_ops.o \
+       xencomm.o xcom_hcall.o grant-table.o
diff --git a/arch/ia64/xen/xen_pv_ops.c b/arch/ia64/xen/xen_pv_ops.c
new file mode 100644
index 0000000..77db214
--- /dev/null
+++ b/arch/ia64/xen/xen_pv_ops.c
@@ -0,0 +1,65 @@
+/******************************************************************************
+ * arch/ia64/xen/xen_pv_ops.c
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/console.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/pm.h>
+
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/xencomm.h>
+#include <asm/xen/privop.h>
+
+/***************************************************************************
+ * general info
+ */
+static struct pv_info xen_info __initdata = {
+       .kernel_rpl = 2,        /* or 1: determin at runtime */
+       .paravirt_enabled = 1,
+       .name = "Xen/ia64",
+};
+
+#define IA64_RSC_PL_SHIFT      2
+#define IA64_RSC_PL_BIT_SIZE   2
+#define IA64_RSC_PL_MASK       \
+       (((1UL << IA64_RSC_PL_BIT_SIZE) - 1) << IA64_RSC_PL_SHIFT)
+
+static void __init
+xen_info_init(void)
+{
+       /* Xenified Linux/ia64 may run on pl = 1 or 2.
+        * determin at run time. */
+       unsigned long rsc = ia64_getreg(_IA64_REG_AR_RSC);
+       unsigned int rpl = (rsc & IA64_RSC_PL_MASK) >> IA64_RSC_PL_SHIFT;
+       xen_info.kernel_rpl = rpl;
+}
+
+/***************************************************************************
+ * pv_ops initialization
+ */
+
+void __init
+xen_setup_pv_ops(void)
+{
+       xen_info_init();
+       pv_info = xen_info;
+}
diff --git a/arch/ia64/xen/xensetup.S b/arch/ia64/xen/xensetup.S
new file mode 100644
index 0000000..43608b2
--- /dev/null
+++ b/arch/ia64/xen/xensetup.S
@@ -0,0 +1,49 @@
+/*
+ * Support routines for Xen
+ *
+ * Copyright (C) 2005 Dan Magenheimer <dan.magenheimer@xxxxxx>
+ */
+
+#include <asm/processor.h>
+#include <asm/asmmacro.h>
+#include <asm/xen/privop.h>
+
+       .section .data.read_mostly
+       .align 8
+       .global running_on_xen
+running_on_xen:
+       data4 0
+       .previous
+
+#define isBP   p3      // are we the Bootstrap Processor?
+
+       .text
+GLOBAL_ENTRY(early_xen_setup)
+       mov r8=ar.rsc           // Initialized in head.S
+(isBP) movl r9=running_on_xen;;
+       extr.u r8=r8,2,2;;      // Extract pl fields
+       cmp.eq p7,p0=r8,r0      // p7: !running on xen
+       mov r8=1                // booleanize.
+(p7)   br.ret.sptk.many rp;;
+(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(early_xen_setup)
-- 
1.5.3


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