Assert correct granularity when mapping a PA

Each translation table level entry can only map a given virtual
address onto physical addresses of the same granularity. For example,
with the current configuration, a level 2 entry maps blocks of 2 MB,
so the physical address must be aligned to 2 MB. If the address is not
aligned, the MMU will just ignore the lower bits.

This patch adds an assertion to make sure that physical addresses are
always aligned to the correct boundary.

Change-Id: I0ab43df71829d45cdbe323301b3053e08ca99c2c
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

include/lib/xlat_tables.h

@@ -93,6 +93,11 @@
 #define L2_XLAT_ADDRESS_SHIFT	(L3_XLAT_ADDRESS_SHIFT + XLAT_TABLE_ENTRIES_SHIFT)
 #define L1_XLAT_ADDRESS_SHIFT	(L2_XLAT_ADDRESS_SHIFT + XLAT_TABLE_ENTRIES_SHIFT)
 #define L0_XLAT_ADDRESS_SHIFT	(L1_XLAT_ADDRESS_SHIFT + XLAT_TABLE_ENTRIES_SHIFT)
+#define XLAT_ADDR_SHIFT(level)	(PAGE_SIZE_SHIFT + \
+		  ((XLAT_TABLE_LEVEL_MAX - (level)) * XLAT_TABLE_ENTRIES_SHIFT))
+
+#define XLAT_BLOCK_SIZE(level)	((u_register_t)1 << XLAT_ADDR_SHIFT(level))
+#define XLAT_BLOCK_MASK(level)	(XLAT_BLOCK_SIZE(level) - 1)
 
 /*
  * AP[1] bit is ignored by hardware and is

lib/xlat_tables/xlat_tables_common.c

@@ -198,6 +198,9 @@ static uint64_t mmap_desc(unsigned attr, unsigned long long addr_pa,
 	uint64_t desc;
 	int mem_type;
 
+	/* Make sure that the granularity is fine enough to map this address. */
+	assert((addr_pa & XLAT_BLOCK_MASK(level)) == 0);
+
 	desc = addr_pa;
 	/*
 	 * There are different translation table descriptors for level 3 and the