[Xen-devel] [PATCH 5 of 6] arm: allow ourselves access to all coprocessors in non-secure mode

[Tim Deegan <tim@xxxxxxx>]

# HG changeset patch
# User Tim Deegan <tim@xxxxxxx>
# Date 1338482127 -3600
# Node ID 9570c43c07f397d8d4a8e725698c17c10c034d80
# Parent  89f363564aa68dcb78d3aedd6a0b24f9bb1ffc13
arm: allow ourselves access to all coprocessors in non-secure mode

We'll need it to be able top use the VFP extensions, for example.

Signed-off-by: Tim Deegan <tim@xxxxxxx>

diff -r 89f363564aa6 -r 9570c43c07f3 xen/arch/arm/mode_switch.S
--- a/xen/arch/arm/mode_switch.S        Thu May 31 17:35:27 2012 +0100
+++ b/xen/arch/arm/mode_switch.S        Thu May 31 17:35:27 2012 +0100
@@ -65,7 +65,10 @@ enter_hyp_mode:
        mov   r0, #0
        mcr   CP32(r0, FCSEIDR)
        mcr   CP32(r0, CONTEXTIDR)
-       /* FIXME: ought to reset some other NS control regs here */
+       /* Allow non-secure access to coprocessors, FIQs, VFP and NEON */
+       ldr   r1, =0x3fff            /* 14 CP bits set, all others clear */
+       mcr   CP32(r1, NSACR)
+
        mrs   r0, cpsr               /* Copy the CPSR */
        add   r0, r0, #0x4           /* 0x16 (Monitor) -> 0x1a (Hyp) */
        msr   spsr_cxsf, r0          /* into the SPSR */

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