[PATCH v2 3/7] ARM: KVM: handle 64bit values passed to mrcc or from mcrr instructions in BE case

Victor Kamensky victor.kamensky at linaro.org
Wed Feb 12 00:41:29 EST 2014


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 at linaro.org>
---
 arch/arm/include/asm/kvm_asm.h | 23 +++++++++++++++++++++--
 arch/arm/kvm/init.S            |  4 ++--
 arch/arm/kvm/interrupts.S      |  4 ++--
 arch/arm/kvm/interrupts_head.S | 18 +++++++++---------
 4 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 661da11..c6ae937 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -26,9 +26,9 @@
 #define c1_ACTLR	4	/* Auxilliary Control Register */
 #define c1_CPACR	5	/* Coprocessor Access Control */
 #define c2_TTBR0	6	/* Translation Table Base Register 0 */
-#define c2_TTBR0_high	7	/* TTBR0 top 32 bits */
+#define c2_TTBR0_hilo	7	/* TTBR0 top 32 bits in LE case, low 32 bits in BE case */
 #define c2_TTBR1	8	/* Translation Table Base Register 1 */
-#define c2_TTBR1_high	9	/* TTBR1 top 32 bits */
+#define c2_TTBR1_hilo	9	/* TTBR1 top 32 bits in LE case, low 32 bits in BE case */
 #define c2_TTBCR	10	/* Translation Table Base Control R. */
 #define c3_DACR		11	/* Domain Access Control Register */
 #define c5_DFSR		12	/* Data Fault Status Register */
@@ -59,6 +59,25 @@
 #define ARM_EXCEPTION_FIQ	  6
 #define ARM_EXCEPTION_HVC	  7
 
+/*
+ * The rr_lo_hi macro swap pair of registers positions depending on
+ * current endianness. It is used in conjunction with ldrd and strd
+ * instructions that loads/store 64 bit value from/to memory to/from
+ * pair of registers which are used with the mrrc and mcrr instructions.
+ * The a1 parameter is register that typically holds lower address
+ * word (least significant word in LE, most significant in BE). The
+ * a2 parameter is register that holds higher address word. Note
+ * within word (single register) the ldrd/strd instruction already
+ * swap data correctly, only additional manipulation required with order
+ * of register to have effect of 64 bit value beeing effectively
+ * swapped.
+ */
+#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 74f0718..2d10b2d 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -74,7 +74,7 @@ __do_hyp_init:
 ARM_BE8(setend	be) @ Switch to Big Endian mode if needed
 
 	@ 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.
@@ -140,7 +140,7 @@ 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 ddc1553..f0696bd 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 1e9be2f..3409ed6 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -252,8 +252,8 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	mrc	p15, 0, r3, c1, c0, 2	@ CPACR
 	mrc	p15, 0, r4, c2, c0, 2	@ TTBCR
 	mrc	p15, 0, r5, c3, c0, 0	@ DACR
-	mrrc	p15, 0, r6, r7, c2	@ TTBR 0
-	mrrc	p15, 1, r8, r9, c2	@ TTBR 1
+	mrrc	p15, 0, rr_lo_hi(r6, r7), c2	@ TTBR 0
+	mrrc	p15, 1, rr_lo_hi(r8, r9), c2	@ TTBR 1
 	mrc	p15, 0, r10, c10, c2, 0	@ PRRR
 	mrc	p15, 0, r11, c10, c2, 1	@ NMRR
 	mrc	p15, 2, r12, c0, c0, 0	@ CSSELR
@@ -303,7 +303,7 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	.endif
 
 	mrc	p15, 0, r2, c14, c1, 0	@ CNTKCTL
-	mrrc	p15, 0, r4, r5, c7	@ PAR
+	mrrc	p15, 0, rr_lo_hi(r4, r5), c7	@ PAR
 
 	.if \store_to_vcpu == 0
 	push	{r2,r4-r5}
@@ -331,7 +331,7 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	.endif
 
 	mcr	p15, 0, r2, c14, c1, 0	@ CNTKCTL
-	mcrr	p15, 0, r4, r5, c7	@ PAR
+	mcrr	p15, 0, rr_lo_hi(r4, r5), c7	@ PAR
 
 	.if \read_from_vcpu == 0
 	pop	{r2-r12}
@@ -381,8 +381,8 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	mcr	p15, 0, r3, c1, c0, 2	@ CPACR
 	mcr	p15, 0, r4, c2, c0, 2	@ TTBCR
 	mcr	p15, 0, r5, c3, c0, 0	@ DACR
-	mcrr	p15, 0, r6, r7, c2	@ TTBR 0
-	mcrr	p15, 1, r8, r9, c2	@ TTBR 1
+	mcrr	p15, 0, rr_lo_hi(r6, r7), c2	@ TTBR 0
+	mcrr	p15, 1, rr_lo_hi(r8, r9), c2	@ TTBR 1
 	mcr	p15, 0, r10, c10, c2, 0	@ PRRR
 	mcr	p15, 0, r11, c10, c2, 1	@ NMRR
 	mcr	p15, 2, r12, c0, c0, 0	@ CSSELR
@@ -512,7 +512,7 @@ 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]
@@ -552,12 +552,12 @@ 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]
-- 
1.8.1.4




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