From: Punit Agrawal <punit.agrawal@arm.com>
Date: Fri, 21 Apr 2017 13:12:54 +0000 (+0100)
Subject: xen/arm: Don't unflatten DT when booting with ACPI
X-Git-Tag: 4.9.0-rc3~12
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=07abf27c0fcb53f1bdba58ef1748af36a6f5cb6c;p=xen.git

xen/arm: Don't unflatten DT when booting with ACPI

Unflattening the device tree when booting with "acpi=force" leads to the
following stack trace on AMD Seattle platform -

(XEN) Xen call trace:
(XEN)    [<0000000000204bfc>] dt_irq_translate+0x48/0x58 (PC)
(XEN)    [<0000000000204f5c>] dt_device_get_irq+0x34/0x38 (LR)
(XEN)    [<0000000000251a08>] platform_get_irq+0x14/0x44
(XEN)    [<00000000002952bc>] smmu.c#arm_smmu_dt_init+0x190/0x100c
(XEN)    [<0000000000299310>] device_init+0xa8/0xdc
(XEN)    [<00000000002950f0>] iommu_hardware_setup+0x34/0x68
(XEN)    [<0000000000294ef0>] iommu_setup+0x48/0x1c8
(XEN)    [<000000000029cecc>] start_xen+0xb94/0xd34
(XEN)    [<00000083fbba91dc>] 00000083fbba91dc

The problem arises due to the unflattened device tree being
unconditionally used in iommu_hardware_setup().

Let's re-arrange the code without changing boot order to unflatten the
device tree only when acpi is disabled.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index e2cda1f134..f00f29a45b 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -757,16 +757,18 @@ void __init start_xen(unsigned long boot_phys_offset,
     /* Parse the ACPI tables for possible boot-time configuration */
     acpi_boot_table_init();
 
+    end_boot_allocator();
+
+    vm_init();
+
     if ( acpi_disabled )
+    {
         printk("Booting using Device Tree\n");
+        dt_unflatten_host_device_tree();
+    }
     else
         printk("Booting using ACPI\n");
 
-    end_boot_allocator();
-
-    vm_init();
-    dt_unflatten_host_device_tree();
-
     init_IRQ();
 
     platform_init();