[PATCH 3.14 034/238] ARM/ARM64: KVM: Nuke Hyp-mode tlbs before enabling MMU

From: Greg Kroah-Hartman
Date: Fri Oct 03 2014 - 20:03:39 EST


3.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>

commit f6edbbf36da3a27b298b66c7955fc84e1dcca305 upstream.

X-Gene u-boot runs in EL2 mode with MMU enabled hence we might
have stale EL2 tlb enteris when we enable EL2 MMU on each host CPU.

This can happen on any ARM/ARM64 board running bootloader in
Hyp-mode (or EL2-mode) with MMU enabled.

This patch ensures that we flush all Hyp-mode (or EL2-mode) TLBs
on each host CPU before enabling Hyp-mode (or EL2-mode) MMU.

Tested-by: Mark Rutland <mark.rutland@xxxxxxx>
Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>
Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/arm/kvm/init.S | 4 ++++
arch/arm64/kvm/hyp-init.S | 4 ++++
2 files changed, 8 insertions(+)

--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -98,6 +98,10 @@ __do_hyp_init:
mrc p15, 0, r0, c10, c2, 1
mcr p15, 4, r0, c10, c2, 1

+ @ Invalidate the stale TLBs from Bootloader
+ mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH
+ dsb ish
+
@ Set the HSCTLR to:
@ - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
@ - Endianness: Kernel config
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -74,6 +74,10 @@ __do_hyp_init:
msr mair_el2, x4
isb

+ /* Invalidate the stale TLBs from Bootloader */
+ tlbi alle2
+ dsb sy
+
mrs x4, sctlr_el2
and x4, x4, #SCTLR_EL2_EE // preserve endianness of EL2
ldr x5, =SCTLR_EL2_FLAGS


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