arm: introduce invalidate_dcache_va_range

Take care of handling non-cacheline aligned addresses and sizes.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

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

@@ -19,6 +19,9 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
         : : "r" (pte.bits), "r" (p) : "memory");
 }
 
+/* Inline ASM to invalidate dcache on register R (may be an inline asm operand) */
+#define __invalidate_dcache_one(R) STORE_CP32(R, DCIMVAC)
+
 /* Inline ASM to flush dcache on register R (may be an inline asm operand) */
 #define __clean_dcache_one(R) STORE_CP32(R, DCCMVAC)
 

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

@@ -14,6 +14,9 @@ static inline void write_pte(lpae_t *p, lpae_t pte)
         : : "r" (pte.bits), "r" (p) : "memory");
 }
 
+/* Inline ASM to invalidate dcache on register R (may be an inline asm operand) */
+#define __invalidate_dcache_one(R) "dc ivac, %" #R ";"
+
 /* Inline ASM to flush dcache on register R (may be an inline asm operand) */
 #define __clean_dcache_one(R) "dc cvac, %" #R ";"
 

xen/include/asm-arm/page.h

@@ -268,6 +268,38 @@ extern size_t cacheline_bytes;
 /* Functions for flushing medium-sized areas.
  * if 'range' is large enough we might want to use model-specific
  * full-cache flushes. */
+
+static inline int invalidate_dcache_va_range(const void *p, unsigned long size)
+{
+    size_t off;
+    const void *end = p + size;
+
+    dsb(sy);           /* So the CPU issues all writes to the range */
+
+    off = (unsigned long)p % cacheline_bytes;
+    if ( off )
+    {
+        p -= off;
+        asm volatile (__clean_and_invalidate_dcache_one(0) : : "r" (p));
+        p += cacheline_bytes;
+        size -= cacheline_bytes - off;
+    }
+    off = (unsigned long)end % cacheline_bytes;
+    if ( off )
+    {
+        end -= off;
+        size -= off;
+        asm volatile (__clean_and_invalidate_dcache_one(0) : : "r" (end));
+    }
+
+    for ( ; p < end; p += cacheline_bytes )
+        asm volatile (__invalidate_dcache_one(0) : : "r" (p));
+
+    dsb(sy);           /* So we know the flushes happen before continuing */
+
+    return 0;
+}
+
 static inline int clean_dcache_va_range(const void *p, unsigned long size)
 {
     const void *end;