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ARM: 8600/1: Enforce some NS-SVC initialisation

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Since the non-secure copies of banked registers lack architecturally
defined reset values, there is no actual guarantee when entering in Hyp
from secure-only firmware that the Non-Secure PL1 state will look the
way that kernel entry (in particular the decompressor stub) expects.
So far, we've been getting away with it thanks to implementation details
of ARMv7 cores and/or bootloader behaviour, but for the sake of forwards
compatibility let's try to ensure that we have a minimally sane state
before dropping down into it.

Cc: Russell King <linux@armlinux.org.uk>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Robin Murphy 2016-08-19 19:38:41 +01:00 committed by Russell King
parent f271b779f4
commit 1527eda3ab
1 changed files with 13 additions and 0 deletions
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13
arch/arm/kernel/hyp-stub.S
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@ -142,6 +142,19 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
and r7, #0x1f @ Preserve HPMN
mcr p15, 4, r7, c1, c1, 1 @ HDCR
@ Make sure NS-SVC is initialised appropriately
mrc p15, 0, r7, c1, c0, 0 @ SCTLR
orr r7, #(1 << 5) @ CP15 barriers enabled
bic r7, #(3 << 7) @ Clear SED/ITD for v8 (RES0 for v7)
bic r7, #(3 << 19) @ WXN and UWXN disabled
mcr p15, 0, r7, c1, c0, 0 @ SCTLR
mrc p15, 0, r7, c0, c0, 0 @ MIDR
mcr p15, 4, r7, c0, c0, 0 @ VPIDR
mrc p15, 0, r7, c0, c0, 5 @ MPIDR
mcr p15, 4, r7, c0, c0, 5 @ VMPIDR
#if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
@ make CNTP_* and CNTPCT accessible from PL1
mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1