xen: arm64: dcache flush

Use "dsb sy" instead of bare "dsb", they mean the same on 32-bit but only the
former is valid on 64-bit.

Abstract the actual flush operation into a macro.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>

xen/include/asm-arm/arm32/page.h

@@ -23,6 +23,9 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
         : : "r" (pte.bits), "r" (p) : "memory");
 }
 
+/* Inline ASM to flush dcache on register R (may be an inline asm operand) */
+#define __flush_xen_dcache_one(R) STORE_CP32(R, DCCMVAC)
+
 /*
  * Flush all hypervisor mappings from the TLB and branch predictor.
  * This is needed after changing Xen code mappings.

xen/include/asm-arm/arm64/page.h

@@ -18,6 +18,9 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
         : : "r" (pte.bits), "r" (p) : "memory");
 }
 
+/* Inline ASM to flush dcache on register R (may be an inline asm operand) */
+#define __flush_xen_dcache_one(R) "dc cvac, %" #R ";"
+
 /*
  * Flush all hypervisor mappings from the TLB
  * This is needed after changing Xen code mappings.

xen/include/asm-arm/page.h

@@ -251,7 +251,7 @@ static inline void flush_xen_dcache_va_range(void *p, unsigned long size)
     void *end;
     dsb();           /* So the CPU issues all writes to the range */
     for ( end = p + size; p < end; p += cacheline_bytes )
-        WRITE_CP32((uint32_t) p, DCCMVAC);
+        asm volatile (__flush_xen_dcache_one(0) : : "r" (p));
     dsb();           /* So we know the flushes happen before continuing */
 }
 
@@ -264,9 +264,9 @@ static inline void flush_xen_dcache_va_range(void *p, unsigned long size)
         flush_xen_dcache_va_range(_p, sizeof(x));                       \
     else                                                                \
         asm volatile (                                                  \
-            "dsb;"   /* Finish all earlier writes */                    \
-            STORE_CP32(0, DCCMVAC)                                      \
-            "dsb;"   /* Finish flush before continuing */               \
+            "dsb sy;"   /* Finish all earlier writes */                 \
+            __flush_xen_dcache_one(0)                                   \
+            "dsb sy;"   /* Finish flush before continuing */            \
             : : "r" (_p), "m" (*_p));                                   \
 } while (0)