ACPI, APEI, Fix ERST MOVE_DATA instruction implementation

The src_base and dst_base fields in apei_exec_context are physical
address, so they should be ioremaped before being used in ERST
MOVE_DATA instruction.
Reported-by: Javier Martinez Canillas <martinez.javier@gmail.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/apei/erst.c

@@ -266,13 +266,30 @@ static int erst_exec_move_data(struct apei_exec_context *ctx,
 {
 	int rc;
 	u64 offset;
+	void *src, *dst;
+
+	/* ioremap does not work in interrupt context */
+	if (in_interrupt()) {
+		pr_warning(ERST_PFX
+			   "MOVE_DATA can not be used in interrupt context");
+		return -EBUSY;
+	}
 
 	rc = __apei_exec_read_register(entry, &offset);
 	if (rc)
 		return rc;
-	memmove((void *)ctx->dst_base + offset,
-		(void *)ctx->src_base + offset,
-		ctx->var2);
+
+	src = ioremap(ctx->src_base + offset, ctx->var2);
+	if (!src)
+		return -ENOMEM;
+	dst = ioremap(ctx->dst_base + offset, ctx->var2);
+	if (!dst)
+		return -ENOMEM;
+
+	memmove(dst, src, ctx->var2);
+
+	iounmap(src);
+	iounmap(dst);
 
 	return 0;
 }