X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;ds=sidebyside;f=Documentation%2Farm%2FBooting;h=0c1f475fdf36e140d28bcdc26d880546f8a8bdc4;hb=35fd3dc58da675d659513384221349ef90749a01;hp=a341d87d276eb1bf3904aec38896f87174b36561;hpb=538d2882213ef4f076108f3edda2c39a584c4c2b;p=~andy%2Flinux

diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting
index a341d87d276..0c1f475fdf3 100644
--- a/Documentation/arm/Booting
+++ b/Documentation/arm/Booting
@@ -154,13 +154,33 @@ In either case, the following conditions must be met:
 
 - CPU mode
   All forms of interrupts must be disabled (IRQs and FIQs)
-  The CPU must be in SVC mode.  (A special exception exists for Angel)
+
+  For CPUs which do not include the ARM virtualization extensions, the
+  CPU must be in SVC mode.  (A special exception exists for Angel)
+
+  CPUs which include support for the virtualization extensions can be
+  entered in HYP mode in order to enable the kernel to make full use of
+  these extensions.  This is the recommended boot method for such CPUs,
+  unless the virtualisations are already in use by a pre-installed
+  hypervisor.
+
+  If the kernel is not entered in HYP mode for any reason, it must be
+  entered in SVC mode.
 
 - Caches, MMUs
   The MMU must be off.
   Instruction cache may be on or off.
   Data cache must be off.
 
+  If the kernel is entered in HYP mode, the above requirements apply to
+  the HYP mode configuration in addition to the ordinary PL1 (privileged
+  kernel modes) configuration.  In addition, all traps into the
+  hypervisor must be disabled, and PL1 access must be granted for all
+  peripherals and CPU resources for which this is architecturally
+  possible.  Except for entering in HYP mode, the system configuration
+  should be such that a kernel which does not include support for the
+  virtualization extensions can boot correctly without extra help.
+
 - The boot loader is expected to call the kernel image by jumping
   directly to the first instruction of the kernel image.