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authorMarcelo Tosatti <mtosatti@redhat.com>2012-10-30 01:15:32 +0400
committerMarcelo Tosatti <mtosatti@redhat.com>2012-10-30 01:15:32 +0400
commit19bf7f8ac3f8131100027281c495dbbe00cd5ae0 (patch)
tree270b97e3ca47c0f62a1babca2ae37f79a76a309c /Documentation/arm/Booting
parent787c57c0fb393fe8a3974d300ddcfe30373386fe (diff)
parent35fd3dc58da675d659513384221349ef90749a01 (diff)
downloadlinux-19bf7f8ac3f8131100027281c495dbbe00cd5ae0.tar.xz
Merge remote-tracking branch 'master' into queue
Merge reason: development work has dependency on kvm patches merged upstream. Conflicts: arch/powerpc/include/asm/Kbuild arch/powerpc/include/asm/kvm_para.h Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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1 files changed, 21 insertions, 1 deletions
diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting
index a341d87d276e..0c1f475fdf36 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.