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ARM: 8053/1: kernel: sleep: restore HYP mode configuration in cpu_resume

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On CPUs with virtualization extensions the kernel installs HYP mode
configuration on both primary and secondary cpus upon cold boot.

On platforms where CPUs are shutdown in idle paths (ie CPU core gating),
when a CPU resumes from low-power states it currently does not execute
code that reinstalls the HYP configuration, which means that the kernel
cannot run eg KVM properly on such machines.

This patch, mirroring cold-boot behaviour, executes position independent
code that reinstalls HYP configuration and drops to SVC mode safely on
warmboot, so that deep idle states can be enabled in kernel running as
hosts on platforms with power management HW.

Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Lorenzo Pieralisi
2014-05-08 17:31:40 +01:00
committed by Russell King
parent 72e6ae285a
commit 0e0779da22
2 changed files with 5 additions and 2 deletions
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2
arch/arm/include/asm/assembler.h
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@@ -312,7 +312,7 @@
* you cannot return to the original mode.
*/
.macro safe_svcmode_maskall reg:req
#if __LINUX_ARM_ARCH__ >= 6
#if __LINUX_ARM_ARCH__ >= 6 && !defined(CONFIG_CPU_V7M)
mrs \reg , cpsr
eor \reg, \reg, #HYP_MODE
tst \reg, #MODE_MASK