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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 07:32:43 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 07:32:43 +0400
commit5cea24c5899a81abf59706d69580dd5c734effa8 (patch)
treec080ec6b1c6cf27b50f00b2980068fb563b6f7ec /Documentation
parent2fc07efa2241afe08de136c061b3baa103fb286c (diff)
parenta0f0dd57f4a85310d9936f1770a0424b49fef876 (diff)
downloadlinux-5cea24c5899a81abf59706d69580dd5c734effa8.tar.xz
Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm
Pull second set of ARM updates from Russell King: "This is the second set of ARM updates for this merge window. Contained within are changes to allow the kernel to boot in hypervisor mode on CPUs supporting virtualization, and cache flushing support to the point of inner sharable unification, which are used by the suspend/resume code to avoid having to do a full cache flush. Also included is one fix for VFP code identified by Michael Olbrich." * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels ARM: 7549/1: HYP: fix boot on some ARM1136 cores ARM: 7542/1: mm: fix cache LoUIS API for xscale and feroceon ARM: mm: update __v7_setup() to the new LoUIS cache maintenance API ARM: kernel: update __cpu_disable to use cache LoUIS maintenance API ARM: kernel: update cpu_suspend code to use cache LoUIS operations ARM: mm: rename jump labels in v7_flush_dcache_all function ARM: mm: implement LoUIS API for cache maintenance ops ARM: virt: arch_timers: enable access to physical timers ARM: virt: Add CONFIG_ARM_VIRT_EXT option ARM: virt: Add boot-time diagnostics ARM: virt: Update documentation for hyp mode entry support ARM: zImage/virt: hyp mode entry support for the zImage loader ARM: virt: allow the kernel to be entered in HYP mode ARM: opcodes: add __ERET/__MSR_ELR_HYP instruction encoding
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arm/Booting22
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.