ARM: KVM: handle 64bit values passed to mrcc or from mcrr instructions in BE case

In some cases the mcrr and mrrc instructions in combination with the ldrd
and strd instructions need to deal with 64bit value in memory. The ldrd
and strd instructions already handle endianness within word (register)
boundaries but to get effect of the whole 64bit value represented correctly,
rr_lo_hi macro is introduced and is used to swap registers positions when
the mcrr and mrrc instructions are used. That has the effect of swapping
two words.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

4 files changed, 25 insertions, 7 deletions

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 53b3c4a50d5c..3a67bec72d0c 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -61,6 +61,24 @@
 #define ARM_EXCEPTION_FIQ         6
 #define ARM_EXCEPTION_HVC         7
 
+/*
+ * The rr_lo_hi macro swaps a pair of registers depending on
+ * current endianness. It is used in conjunction with ldrd and strd
+ * instructions that load/store a 64-bit value from/to memory to/from
+ * a pair of registers which are used with the mrrc and mcrr instructions.
+ * If used with the ldrd/strd instructions, the a1 parameter is the first
+ * source/destination register and the a2 parameter is the second
+ * source/destination register. Note that the ldrd/strd instructions
+ * already swap the bytes within the words correctly according to the
+ * endianness setting, but the order of the registers need to be effectively
+ * swapped when used with the mrrc/mcrr instructions.
+ */
+#ifdef CONFIG_CPU_ENDIAN_BE8
+#define rr_lo_hi(a1, a2) a2, a1
+#else
+#define rr_lo_hi(a1, a2) a1, a2
+#endif
+
 #ifndef __ASSEMBLY__
 struct kvm;
 struct kvm_vcpu;
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 1b9844d369cc..2cc14dfad049 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -71,7 +71,7 @@ __do_hyp_init:
         bne     phase2                  @ Yes, second stage init
 
         @ Set the HTTBR to point to the hypervisor PGD pointer passed
-        mcrr    p15, 4, r2, r3, c2
+        mcrr    p15, 4, rr_lo_hi(r2, r3), c2
 
         @ Set the HTCR and VTCR to the same shareability and cacheability
         @ settings as the non-secure TTBCR and with T0SZ == 0.
@@ -137,7 +137,7 @@ phase2:
         mov     pc, r0
 
 target: @ We're now in the trampoline code, switch page tables
-        mcrr    p15, 4, r2, r3, c2
+        mcrr    p15, 4, rr_lo_hi(r2, r3), c2
         isb
 
         @ Invalidate the old TLBs
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index 0d68d4073068..24d4e65806a7 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -52,7 +52,7 @@ ENTRY(__kvm_tlb_flush_vmid_ipa)
         dsb     ishst
         add     r0, r0, #KVM_VTTBR
         ldrd    r2, r3, [r0]
-        mcrr    p15, 6, r2, r3, c2      @ Write VTTBR
+        mcrr    p15, 6, rr_lo_hi(r2, r3), c2    @ Write VTTBR
         isb
         mcr     p15, 0, r0, c8, c3, 0   @ TLBIALLIS (rt ignored)
         dsb     ish
@@ -135,7 +135,7 @@ ENTRY(__kvm_vcpu_run)
         ldr     r1, [vcpu, #VCPU_KVM]
         add     r1, r1, #KVM_VTTBR
         ldrd    r2, r3, [r1]
-        mcrr    p15, 6, r2, r3, c2      @ Write VTTBR
+        mcrr    p15, 6, rr_lo_hi(r2, r3), c2    @ Write VTTBR
 
         @ We're all done, just restore the GPRs and go to the guest
         restore_guest_regs
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index 68d99c69639c..98c8c5b9a87f 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -520,7 +520,7 @@ ARM_BE8(rev	r6, r6  )
         mcr     p15, 0, r2, c14, c3, 1  @ CNTV_CTL
         isb
 
-        mrrc    p15, 3, r2, r3, c14     @ CNTV_CVAL
+        mrrc    p15, 3, rr_lo_hi(r2, r3), c14   @ CNTV_CVAL
         ldr     r4, =VCPU_TIMER_CNTV_CVAL
         add     r5, vcpu, r4
         strd    r2, r3, [r5]
@@ -560,12 +560,12 @@ ARM_BE8(rev	r6, r6  )
 
         ldr     r2, [r4, #KVM_TIMER_CNTVOFF]
         ldr     r3, [r4, #(KVM_TIMER_CNTVOFF + 4)]
-        mcrr    p15, 4, r2, r3, c14     @ CNTVOFF
+        mcrr    p15, 4, rr_lo_hi(r2, r3), c14   @ CNTVOFF
 
         ldr     r4, =VCPU_TIMER_CNTV_CVAL
         add     r5, vcpu, r4
         ldrd    r2, r3, [r5]
-        mcrr    p15, 3, r2, r3, c14     @ CNTV_CVAL
+        mcrr    p15, 3, rr_lo_hi(r2, r3), c14   @ CNTV_CVAL
         isb
 
         ldr     r2, [vcpu, #VCPU_TIMER_CNTV_CTL]