[Xen-changelog] [xen-unstable] arm: restore ELR_hyp and SPSR_hyp on return from hypervisor to hypervisor.

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1329921203 0
# Node ID 70aeec92bd0aaabc9fd1718e753ef2cdba5057b8
# Parent  7705f168dee3507aa3246808dd6735ae2016e602
arm: restore ELR_hyp and SPSR_hyp on return from hypervisor to hypervisor.

This is necessary to handle nested traps to the hypervisor more than one deep.

I've not seen an actually failure relating to this but I'm not quite sure how
we've managed to get away with not doing it (I suppose multiply nested traps
are uncommon).

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Committed-by: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
---


diff -r 7705f168dee3 -r 70aeec92bd0a xen/arch/arm/entry.S
--- a/xen/arch/arm/entry.S      Wed Feb 22 14:33:23 2012 +0000
+++ b/xen/arch/arm/entry.S      Wed Feb 22 14:33:23 2012 +0000
@@ -102,6 +102,10 @@
 
 ENTRY(return_to_hypervisor)
        ldr lr, [sp, #UREGS_lr]
+       ldr r11, [sp, #UREGS_pc]
+       msr ELR_hyp, r11
+       ldr r11, [sp, #UREGS_cpsr]
+       msr SPSR_hyp, r11
        pop {r0-r12}
        add sp, #(UREGS_R8_fiq - UREGS_sp); /* SP, LR, SPSR, PC */
        eret

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