lib/xlat_tables_v2/xlat_tables_internal.c

/*
 * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <arch_helpers.h>
#include <assert.h>
#include <common_def.h>
#include <debug.h>
#include <errno.h>
#include <platform_def.h>
#include <string.h>
#include <types.h>
#include <utils.h>
#include <xlat_tables_arch_private.h>
#include <xlat_tables_defs.h>
#include <xlat_tables_v2.h>

#include "xlat_tables_private.h"

/*
 * Each platform can define the size of its physical and virtual address spaces.
 * If the platform hasn't defined one or both of them, default to
 * ADDR_SPACE_SIZE. The latter is deprecated, though.
 */
#if ERROR_DEPRECATED
# ifdef ADDR_SPACE_SIZE
#  error "ADDR_SPACE_SIZE is deprecated. Use PLAT_xxx_ADDR_SPACE_SIZE instead."
# endif
#elif defined(ADDR_SPACE_SIZE)
# ifndef PLAT_PHY_ADDR_SPACE_SIZE
#  define PLAT_PHY_ADDR_SPACE_SIZE	ADDR_SPACE_SIZE
# endif
# ifndef PLAT_VIRT_ADDR_SPACE_SIZE
#  define PLAT_VIRT_ADDR_SPACE_SIZE	ADDR_SPACE_SIZE
# endif
#endif

/*
 * Allocate and initialise the default translation context for the BL image
 * currently executing.
 */
REGISTER_XLAT_CONTEXT(tf, MAX_MMAP_REGIONS, MAX_XLAT_TABLES,
		PLAT_VIRT_ADDR_SPACE_SIZE, PLAT_PHY_ADDR_SPACE_SIZE);

#if PLAT_XLAT_TABLES_DYNAMIC

/*
 * The following functions assume that they will be called using subtables only.
 * The base table can't be unmapped, so it is not needed to do any special
 * handling for it.
 */

/*
 * Returns the index of the array corresponding to the specified translation
 * table.
 */
static int xlat_table_get_index(xlat_ctx_t *ctx, const uint64_t *table)
{
	for (unsigned int i = 0; i < ctx->tables_num; i++)
		if (ctx->tables[i] == table)
			return i;

	/*
	 * Maybe we were asked to get the index of the base level table, which
	 * should never happen.
	 */
	assert(0);

	return -1;
}

/* Returns a pointer to an empty translation table. */
static uint64_t *xlat_table_get_empty(xlat_ctx_t *ctx)
{
	for (unsigned int i = 0; i < ctx->tables_num; i++)
		if (ctx->tables_mapped_regions[i] == 0)
			return ctx->tables[i];

	return NULL;
}

/* Increments region count for a given table. */
static void xlat_table_inc_regions_count(xlat_ctx_t *ctx, const uint64_t *table)
{
	ctx->tables_mapped_regions[xlat_table_get_index(ctx, table)]++;
}

/* Decrements region count for a given table. */
static void xlat_table_dec_regions_count(xlat_ctx_t *ctx, const uint64_t *table)
{
	ctx->tables_mapped_regions[xlat_table_get_index(ctx, table)]--;
}

/* Returns 0 if the speficied table isn't empty, otherwise 1. */
static int xlat_table_is_empty(xlat_ctx_t *ctx, const uint64_t *table)
{
	return !ctx->tables_mapped_regions[xlat_table_get_index(ctx, table)];
}

#else /* PLAT_XLAT_TABLES_DYNAMIC */

/* Returns a pointer to the first empty translation table. */
static uint64_t *xlat_table_get_empty(xlat_ctx_t *ctx)
{
	assert(ctx->next_table < ctx->tables_num);

	return ctx->tables[ctx->next_table++];
}

#endif /* PLAT_XLAT_TABLES_DYNAMIC */

/*
 * Returns a block/page table descriptor for the given level and attributes.
 */
static uint64_t xlat_desc(const xlat_ctx_t *ctx, uint32_t attr,
			  unsigned long long addr_pa, int level)
{
	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
	 * rest.
	 */
	desc |= (level == XLAT_TABLE_LEVEL_MAX) ? PAGE_DESC : BLOCK_DESC;
	/*
	 * Always set the access flag, as TF doesn't manage access flag faults.
	 * Deduce other fields of the descriptor based on the MT_NS and MT_RW
	 * memory region attributes.
	 */
	desc |= LOWER_ATTRS(ACCESS_FLAG);

	desc |= (attr & MT_NS) ? LOWER_ATTRS(NS) : 0;
	desc |= (attr & MT_RW) ? LOWER_ATTRS(AP_RW) : LOWER_ATTRS(AP_RO);

	/*
	 * Do not allow unprivileged access when the mapping is for a privileged
	 * EL. For translation regimes that do not have mappings for access for
	 * lower exception levels, set AP[2] to AP_NO_ACCESS_UNPRIVILEGED.
	 */
	if (ctx->xlat_regime == EL1_EL0_REGIME) {
		if (attr & MT_USER) {
			/* EL0 mapping requested, so we give User access */
			desc |= LOWER_ATTRS(AP_ACCESS_UNPRIVILEGED);
		} else {
			/* EL1 mapping requested, no User access granted */
			desc |= LOWER_ATTRS(AP_NO_ACCESS_UNPRIVILEGED);
		}
	} else {
		assert(ctx->xlat_regime == EL3_REGIME);
		desc |= LOWER_ATTRS(AP_ONE_VA_RANGE_RES1);
	}

	/*
	 * Deduce shareability domain and executability of the memory region
	 * from the memory type of the attributes (MT_TYPE).
	 *
	 * Data accesses to device memory and non-cacheable normal memory are
	 * coherent for all observers in the system, and correspondingly are
	 * always treated as being Outer Shareable. Therefore, for these 2 types
	 * of memory, it is not strictly needed to set the shareability field
	 * in the translation tables.
	 */
	mem_type = MT_TYPE(attr);
	if (mem_type == MT_DEVICE) {
		desc |= LOWER_ATTRS(ATTR_DEVICE_INDEX | OSH);
		/*
		 * Always map device memory as execute-never.
		 * This is to avoid the possibility of a speculative instruction
		 * fetch, which could be an issue if this memory region
		 * corresponds to a read-sensitive peripheral.
		 */
		desc |= xlat_arch_regime_get_xn_desc(ctx->xlat_regime);

	} else { /* Normal memory */
		/*
		 * Always map read-write normal memory as execute-never.
		 * (Trusted Firmware doesn't self-modify its code, therefore
		 * R/W memory is reserved for data storage, which must not be
		 * executable.)
		 * Note that setting the XN bit here is for consistency only.
		 * The function that enables the MMU sets the SCTLR_ELx.WXN bit,
		 * which makes any writable memory region to be treated as
		 * execute-never, regardless of the value of the XN bit in the
		 * translation table.
		 *
		 * For read-only memory, rely on the MT_EXECUTE/MT_EXECUTE_NEVER
		 * attribute to figure out the value of the XN bit.  The actual
		 * XN bit(s) to set in the descriptor depends on the context's
		 * translation regime and the policy applied in
		 * xlat_arch_regime_get_xn_desc().
		 */
		if ((attr & MT_RW) || (attr & MT_EXECUTE_NEVER)) {
			desc |= xlat_arch_regime_get_xn_desc(ctx->xlat_regime);
		}

		if (mem_type == MT_MEMORY) {
			desc |= LOWER_ATTRS(ATTR_IWBWA_OWBWA_NTR_INDEX | ISH);
		} else {
			assert(mem_type == MT_NON_CACHEABLE);
			desc |= LOWER_ATTRS(ATTR_NON_CACHEABLE_INDEX | OSH);
		}
	}

	return desc;
}

/*
 * Enumeration of actions that can be made when mapping table entries depending
 * on the previous value in that entry and information about the region being
 * mapped.
 */
typedef enum {

	/* Do nothing */
	ACTION_NONE,

	/* Write a block (or page, if in level 3) entry. */
	ACTION_WRITE_BLOCK_ENTRY,

	/*
	 * Create a new table and write a table entry pointing to it. Recurse
	 * into it for further processing.
	 */
	ACTION_CREATE_NEW_TABLE,

	/*
	 * There is a table descriptor in this entry, read it and recurse into
	 * that table for further processing.
	 */
	ACTION_RECURSE_INTO_TABLE,

} action_t;

#if PLAT_XLAT_TABLES_DYNAMIC

/*
 * Recursive function that writes to the translation tables and unmaps the
 * specified region.
 */
static void xlat_tables_unmap_region(xlat_ctx_t *ctx, mmap_region_t *mm,
				     const uintptr_t table_base_va,
				     uint64_t *const table_base,
				     const int table_entries,
				     const unsigned int level)
{
	assert(level >= ctx->base_level && level <= XLAT_TABLE_LEVEL_MAX);

	uint64_t *subtable;
	uint64_t desc;

	uintptr_t table_idx_va;
	uintptr_t table_idx_end_va; /* End VA of this entry */

	uintptr_t region_end_va = mm->base_va + mm->size - 1;

	int table_idx;

	if (mm->base_va > table_base_va) {
		/* Find the first index of the table affected by the region. */
		table_idx_va = mm->base_va & ~XLAT_BLOCK_MASK(level);

		table_idx = (table_idx_va - table_base_va) >>
			    XLAT_ADDR_SHIFT(level);

		assert(table_idx < table_entries);
	} else {
		/* Start from the beginning of the table. */
		table_idx_va = table_base_va;
		table_idx = 0;
	}

	while (table_idx < table_entries) {

		table_idx_end_va = table_idx_va + XLAT_BLOCK_SIZE(level) - 1;

		desc = table_base[table_idx];
		uint64_t desc_type = desc & DESC_MASK;

		action_t action = ACTION_NONE;

		if ((mm->base_va <= table_idx_va) &&
		    (region_end_va >= table_idx_end_va)) {

			/* Region covers all block */

			if (level == 3) {
				/*
				 * Last level, only page descriptors allowed,
				 * erase it.
				 */
				assert(desc_type == PAGE_DESC);

				action = ACTION_WRITE_BLOCK_ENTRY;
			} else {
				/*
				 * Other levels can have table descriptors. If
				 * so, recurse into it and erase descriptors
				 * inside it as needed. If there is a block
				 * descriptor, just erase it. If an invalid
				 * descriptor is found, this table isn't
				 * actually mapped, which shouldn't happen.
				 */
				if (desc_type == TABLE_DESC) {
					action = ACTION_RECURSE_INTO_TABLE;
				} else {
					assert(desc_type == BLOCK_DESC);
					action = ACTION_WRITE_BLOCK_ENTRY;
				}
			}

		} else if ((mm->base_va <= table_idx_end_va) ||
			   (region_end_va >= table_idx_va)) {

			/*
			 * Region partially covers block.
			 *
			 * It can't happen in level 3.
			 *
			 * There must be a table descriptor here, if not there
			 * was a problem when mapping the region.
			 */

			assert(level < 3);

			assert(desc_type == TABLE_DESC);

			action = ACTION_RECURSE_INTO_TABLE;
		}

		if (action == ACTION_WRITE_BLOCK_ENTRY) {

			table_base[table_idx] = INVALID_DESC;
			xlat_arch_tlbi_va_regime(table_idx_va, ctx->xlat_regime);

		} else if (action == ACTION_RECURSE_INTO_TABLE) {

			subtable = (uint64_t *)(uintptr_t)(desc & TABLE_ADDR_MASK);

			/* Recurse to write into subtable */
			xlat_tables_unmap_region(ctx, mm, table_idx_va,
						 subtable, XLAT_TABLE_ENTRIES,
						 level + 1);

			/*
			 * If the subtable is now empty, remove its reference.
			 */
			if (xlat_table_is_empty(ctx, subtable)) {
				table_base[table_idx] = INVALID_DESC;
				xlat_arch_tlbi_va_regime(table_idx_va,
						ctx->xlat_regime);
			}

		} else {
			assert(action == ACTION_NONE);
		}

		table_idx++;
		table_idx_va += XLAT_BLOCK_SIZE(level);

		/* If reached the end of the region, exit */
		if (region_end_va <= table_idx_va)
			break;
	}

	if (level > ctx->base_level)
		xlat_table_dec_regions_count(ctx, table_base);
}

#endif /* PLAT_XLAT_TABLES_DYNAMIC */

/*
 * From the given arguments, it decides which action to take when mapping the
 * specified region.
 */
static action_t xlat_tables_map_region_action(const mmap_region_t *mm,
		const int desc_type, const unsigned long long dest_pa,
		const uintptr_t table_entry_base_va, const unsigned int level)
{
	uintptr_t mm_end_va = mm->base_va + mm->size - 1;
	uintptr_t table_entry_end_va =
			table_entry_base_va + XLAT_BLOCK_SIZE(level) - 1;

	/*
	 * The descriptor types allowed depend on the current table level.
	 */

	if ((mm->base_va <= table_entry_base_va) &&
	    (mm_end_va >= table_entry_end_va)) {

		/*
		 * Table entry is covered by region
		 * --------------------------------
		 *
		 * This means that this table entry can describe the whole
		 * translation with this granularity in principle.
		 */

		if (level == 3) {
			/*
			 * Last level, only page descriptors are allowed.
			 */
			if (desc_type == PAGE_DESC) {
				/*
				 * There's another region mapped here, don't
				 * overwrite.
				 */
				return ACTION_NONE;
			} else {
				assert(desc_type == INVALID_DESC);
				return ACTION_WRITE_BLOCK_ENTRY;
			}

		} else {

			/*
			 * Other levels. Table descriptors are allowed. Block
			 * descriptors too, but they have some limitations.
			 */

			if (desc_type == TABLE_DESC) {
				/* There's already a table, recurse into it. */
				return ACTION_RECURSE_INTO_TABLE;

			} else if (desc_type == INVALID_DESC) {
				/*
				 * There's nothing mapped here, create a new
				 * entry.
				 *
				 * Check if the destination granularity allows
				 * us to use a block descriptor or we need a
				 * finer table for it.
				 *
				 * Also, check if the current level allows block
				 * descriptors. If not, create a table instead.
				 */
				if ((dest_pa & XLAT_BLOCK_MASK(level)) ||
				    (level < MIN_LVL_BLOCK_DESC) ||
				    (mm->granularity < XLAT_BLOCK_SIZE(level)))
					return ACTION_CREATE_NEW_TABLE;
				else
					return ACTION_WRITE_BLOCK_ENTRY;

			} else {
				/*
				 * There's another region mapped here, don't
				 * overwrite.
				 */
				assert(desc_type == BLOCK_DESC);

				return ACTION_NONE;
			}
		}

	} else if ((mm->base_va <= table_entry_end_va) ||
		   (mm_end_va >= table_entry_base_va)) {

		/*
		 * Region partially covers table entry
		 * -----------------------------------
		 *
		 * This means that this table entry can't describe the whole
		 * translation, a finer table is needed.

		 * There cannot be partial block overlaps in level 3. If that
		 * happens, some of the preliminary checks when adding the
		 * mmap region failed to detect that PA and VA must at least be
		 * aligned to PAGE_SIZE.
		 */
		assert(level < 3);

		if (desc_type == INVALID_DESC) {
			/*
			 * The block is not fully covered by the region. Create
			 * a new table, recurse into it and try to map the
			 * region with finer granularity.
			 */
			return ACTION_CREATE_NEW_TABLE;

		} else {
			assert(desc_type == TABLE_DESC);
			/*
			 * The block is not fully covered by the region, but
			 * there is already a table here. Recurse into it and
			 * try to map with finer granularity.
			 *
			 * PAGE_DESC for level 3 has the same value as
			 * TABLE_DESC, but this code can't run on a level 3
			 * table because there can't be overlaps in level 3.
			 */
			return ACTION_RECURSE_INTO_TABLE;
		}
	}

	/*
	 * This table entry is outside of the region specified in the arguments,
	 * don't write anything to it.
	 */
	return ACTION_NONE;
}

/*
 * Recursive function that writes to the translation tables and maps the
 * specified region. On success, it returns the VA of the last byte that was
 * succesfully mapped. On error, it returns the VA of the next entry that
 * should have been mapped.
 */
static uintptr_t xlat_tables_map_region(xlat_ctx_t *ctx, mmap_region_t *mm,
				   const uintptr_t table_base_va,
				   uint64_t *const table_base,
				   const int table_entries,
				   const unsigned int level)
{
	assert(level >= ctx->base_level && level <= XLAT_TABLE_LEVEL_MAX);

	uintptr_t mm_end_va = mm->base_va + mm->size - 1;

	uintptr_t table_idx_va;
	unsigned long long table_idx_pa;

	uint64_t *subtable;
	uint64_t desc;

	int table_idx;

	if (mm->base_va > table_base_va) {
		/* Find the first index of the table affected by the region. */
		table_idx_va = mm->base_va & ~XLAT_BLOCK_MASK(level);

		table_idx = (table_idx_va - table_base_va) >>
			    XLAT_ADDR_SHIFT(level);

		assert(table_idx < table_entries);
	} else {
		/* Start from the beginning of the table. */
		table_idx_va = table_base_va;
		table_idx = 0;
	}

#if PLAT_XLAT_TABLES_DYNAMIC
	if (level > ctx->base_level)
		xlat_table_inc_regions_count(ctx, table_base);
#endif

	while (table_idx < table_entries) {

		desc = table_base[table_idx];

		table_idx_pa = mm->base_pa + table_idx_va - mm->base_va;

		action_t action = xlat_tables_map_region_action(mm,
			desc & DESC_MASK, table_idx_pa, table_idx_va, level);

		if (action == ACTION_WRITE_BLOCK_ENTRY) {

			table_base[table_idx] =
				xlat_desc(ctx, (uint32_t)mm->attr, table_idx_pa,
					  level);

		} else if (action == ACTION_CREATE_NEW_TABLE) {

			subtable = xlat_table_get_empty(ctx);
			if (subtable == NULL) {
				/* Not enough free tables to map this region */
				return table_idx_va;
			}

			/* Point to new subtable from this one. */
			table_base[table_idx] = TABLE_DESC | (unsigned long)subtable;

			/* Recurse to write into subtable */
			uintptr_t end_va = xlat_tables_map_region(ctx, mm, table_idx_va,
					       subtable, XLAT_TABLE_ENTRIES,
					       level + 1);
			if (end_va != table_idx_va + XLAT_BLOCK_SIZE(level) - 1)
				return end_va;

		} else if (action == ACTION_RECURSE_INTO_TABLE) {

			subtable = (uint64_t *)(uintptr_t)(desc & TABLE_ADDR_MASK);
			/* Recurse to write into subtable */
			uintptr_t end_va =  xlat_tables_map_region(ctx, mm, table_idx_va,
					       subtable, XLAT_TABLE_ENTRIES,
					       level + 1);
			if (end_va != table_idx_va + XLAT_BLOCK_SIZE(level) - 1)
				return end_va;

		} else {

			assert(action == ACTION_NONE);

		}

		table_idx++;
		table_idx_va += XLAT_BLOCK_SIZE(level);

		/* If reached the end of the region, exit */
		if (mm_end_va <= table_idx_va)
			break;
	}

	return table_idx_va - 1;
}

void print_mmap(mmap_region_t *const mmap)
{
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	tf_printf("mmap:\n");
	mmap_region_t *mm = mmap;

	while (mm->size) {
		tf_printf(" VA:%p  PA:0x%llx  size:0x%zx  attr:0x%x",
				(void *)mm->base_va, mm->base_pa,
				mm->size, mm->attr);
		tf_printf(" granularity:0x%zx\n", mm->granularity);
		++mm;
	};
	tf_printf("\n");
#endif
}

/*
 * Function that verifies that a region can be mapped.
 * Returns:
 *        0: Success, the mapping is allowed.
 *   EINVAL: Invalid values were used as arguments.
 *   ERANGE: The memory limits were surpassed.
 *   ENOMEM: There is not enough memory in the mmap array.
 *    EPERM: Region overlaps another one in an invalid way.
 */
static int mmap_add_region_check(xlat_ctx_t *ctx, const mmap_region_t *mm)
{
	unsigned long long base_pa = mm->base_pa;
	uintptr_t base_va = mm->base_va;
	size_t size = mm->size;
	size_t granularity = mm->granularity;

	unsigned long long end_pa = base_pa + size - 1;
	uintptr_t end_va = base_va + size - 1;

	if (!IS_PAGE_ALIGNED(base_pa) || !IS_PAGE_ALIGNED(base_va) ||
			!IS_PAGE_ALIGNED(size))
		return -EINVAL;

	if ((granularity != XLAT_BLOCK_SIZE(1)) &&
		(granularity != XLAT_BLOCK_SIZE(2)) &&
		(granularity != XLAT_BLOCK_SIZE(3))) {
		return -EINVAL;
	}

	/* Check for overflows */
	if ((base_pa > end_pa) || (base_va > end_va))
		return -ERANGE;

	if ((base_va + (uintptr_t)size - (uintptr_t)1) > ctx->va_max_address)
		return -ERANGE;

	if ((base_pa + (unsigned long long)size - 1ULL) > ctx->pa_max_address)
		return -ERANGE;

	/* Check that there is space in the ctx->mmap array */
	if (ctx->mmap[ctx->mmap_num - 1].size != 0)
		return -ENOMEM;

	/* Check for PAs and VAs overlaps with all other regions */
	for (mmap_region_t *mm_cursor = ctx->mmap;
						mm_cursor->size; ++mm_cursor) {

		uintptr_t mm_cursor_end_va = mm_cursor->base_va
							+ mm_cursor->size - 1;

		/*
		 * Check if one of the regions is completely inside the other
		 * one.
		 */
		int fully_overlapped_va =
			((base_va >= mm_cursor->base_va) &&
					(end_va <= mm_cursor_end_va)) ||

			((mm_cursor->base_va >= base_va) &&
						(mm_cursor_end_va <= end_va));

		/*
		 * Full VA overlaps are only allowed if both regions are
		 * identity mapped (zero offset) or have the same VA to PA
		 * offset. Also, make sure that it's not the exact same area.
		 * This can only be done with static regions.
		 */
		if (fully_overlapped_va) {

#if PLAT_XLAT_TABLES_DYNAMIC
			if ((mm->attr & MT_DYNAMIC) ||
						(mm_cursor->attr & MT_DYNAMIC))
				return -EPERM;
#endif /* PLAT_XLAT_TABLES_DYNAMIC */
			if ((mm_cursor->base_va - mm_cursor->base_pa) !=
							(base_va - base_pa))
				return -EPERM;

			if ((base_va == mm_cursor->base_va) &&
						(size == mm_cursor->size))
				return -EPERM;

		} else {
			/*
			 * If the regions do not have fully overlapping VAs,
			 * then they must have fully separated VAs and PAs.
			 * Partial overlaps are not allowed
			 */

			unsigned long long mm_cursor_end_pa =
				     mm_cursor->base_pa + mm_cursor->size - 1;

			int separated_pa =
				(end_pa < mm_cursor->base_pa) ||
				(base_pa > mm_cursor_end_pa);
			int separated_va =
				(end_va < mm_cursor->base_va) ||
				(base_va > mm_cursor_end_va);

			if (!(separated_va && separated_pa))
				return -EPERM;
		}
	}

	return 0;
}

void mmap_add_region_ctx(xlat_ctx_t *ctx, const mmap_region_t *mm)
{
	mmap_region_t *mm_cursor = ctx->mmap, *mm_destination;
	const mmap_region_t *mm_end = ctx->mmap + ctx->mmap_num;
	mmap_region_t *mm_last;
	unsigned long long end_pa = mm->base_pa + mm->size - 1;
	uintptr_t end_va = mm->base_va + mm->size - 1;
	int ret;

	/* Ignore empty regions */
	if (!mm->size)
		return;

	/* Static regions must be added before initializing the xlat tables. */
	assert(!ctx->initialized);

	ret = mmap_add_region_check(ctx, mm);
	if (ret != 0) {
		ERROR("mmap_add_region_check() failed. error %d\n", ret);
		assert(0);
		return;
	}

	/*
	 * Find correct place in mmap to insert new region.
	 *
	 * 1 - Lower region VA end first.
	 * 2 - Smaller region size first.
	 *
	 * VA  0                                   0xFF
	 *
	 * 1st |------|
	 * 2nd |------------|
	 * 3rd                 |------|
	 * 4th                            |---|
	 * 5th                                   |---|
	 * 6th                            |----------|
	 * 7th |-------------------------------------|
	 *
	 * This is required for overlapping regions only. It simplifies adding
	 * regions with the loop in xlat_tables_init_internal because the outer
	 * ones won't overwrite block or page descriptors of regions added
	 * previously.
	 *
	 * Overlapping is only allowed for static regions.
	 */

	while ((mm_cursor->base_va + mm_cursor->size - 1) < end_va
	       && mm_cursor->size)
		++mm_cursor;

	while ((mm_cursor->base_va + mm_cursor->size - 1 == end_va) &&
	       (mm_cursor->size != 0U) && (mm_cursor->size < mm->size))
		++mm_cursor;

	/*
	 * Find the last entry marker in the mmap
	 */
	mm_last = ctx->mmap;
	while ((mm_last->size != 0U) && (mm_last < mm_end)) {
		++mm_last;
	}

	/*
	 * Check if we have enough space in the memory mapping table.
	 * This shouldn't happen as we have checked in mmap_add_region_check
	 * that there is free space.
	 */
	assert(mm_last->size == 0U);
	
	/* Make room for new region by moving other regions up by one place */
	mm_destination = mm_cursor + 1;
	memmove(mm_destination, mm_cursor,
		(uintptr_t)mm_last - (uintptr_t)mm_cursor);

	/*
	 * Check we haven't lost the empty sentinel from the end of the array.
	 * This shouldn't happen as we have checked in mmap_add_region_check
	 * that there is free space.
	 */
	assert(mm_end->size == 0U);

	*mm_cursor = *mm;

	if (end_pa > ctx->max_pa)
		ctx->max_pa = end_pa;
	if (end_va > ctx->max_va)
		ctx->max_va = end_va;
}

void mmap_add_region(unsigned long long base_pa,
				uintptr_t base_va,
				size_t size,
				mmap_attr_t attr)
{
	mmap_region_t mm = MAP_REGION(base_pa, base_va, size, attr);
	mmap_add_region_ctx(&tf_xlat_ctx, &mm);
}


void mmap_add_ctx(xlat_ctx_t *ctx, const mmap_region_t *mm)
{
	while (mm->size) {
		mmap_add_region_ctx(ctx, mm);
		mm++;
	}
}

void mmap_add(const mmap_region_t *mm)
{
	mmap_add_ctx(&tf_xlat_ctx, mm);
}

#if PLAT_XLAT_TABLES_DYNAMIC

int mmap_add_dynamic_region_ctx(xlat_ctx_t *ctx, mmap_region_t *mm)
{
	mmap_region_t *mm_cursor = ctx->mmap;
	mmap_region_t *mm_last = mm_cursor + ctx->mmap_num;
	unsigned long long end_pa = mm->base_pa + mm->size - 1;
	uintptr_t end_va = mm->base_va + mm->size - 1;
	int ret;

	/* Nothing to do */
	if (!mm->size)
		return 0;

	/* Now this region is a dynamic one */
	mm->attr |= MT_DYNAMIC;

	ret = mmap_add_region_check(ctx, mm);
	if (ret != 0)
		return ret;

	/*
	 * Find the adequate entry in the mmap array in the same way done for
	 * static regions in mmap_add_region_ctx().
	 */

	while ((mm_cursor->base_va + mm_cursor->size - 1)
					< end_va && mm_cursor->size)
		++mm_cursor;

	while ((mm_cursor->base_va + mm_cursor->size - 1 == end_va)
				&& (mm_cursor->size < mm->size))
		++mm_cursor;

	/* Make room for new region by moving other regions up by one place */
	memmove(mm_cursor + 1, mm_cursor,
		     (uintptr_t)mm_last - (uintptr_t)mm_cursor);

	/*
	 * Check we haven't lost the empty sentinal from the end of the array.
	 * This shouldn't happen as we have checked in mmap_add_region_check
	 * that there is free space.
	 */
	assert(mm_last->size == 0);

	*mm_cursor = *mm;

	/*
	 * Update the translation tables if the xlat tables are initialized. If
	 * not, this region will be mapped when they are initialized.
	 */
	if (ctx->initialized) {
		uintptr_t end_va = xlat_tables_map_region(ctx, mm_cursor,
				0, ctx->base_table, ctx->base_table_entries,
				ctx->base_level);

		/* Failed to map, remove mmap entry, unmap and return error. */
		if (end_va != mm_cursor->base_va + mm_cursor->size - 1) {
			memmove(mm_cursor, mm_cursor + 1,
				(uintptr_t)mm_last - (uintptr_t)mm_cursor);

			/*
			 * Check if the mapping function actually managed to map
			 * anything. If not, just return now.
			 */
			if (mm->base_va >= end_va)
				return -ENOMEM;

			/*
			 * Something went wrong after mapping some table
			 * entries, undo every change done up to this point.
			 */
			mmap_region_t unmap_mm = {
					.base_pa = 0,
					.base_va = mm->base_va,
					.size = end_va - mm->base_va,
					.attr = 0
			};
			xlat_tables_unmap_region(ctx, &unmap_mm, 0, ctx->base_table,
							ctx->base_table_entries, ctx->base_level);

			return -ENOMEM;
		}

		/*
		 * Make sure that all entries are written to the memory. There
		 * is no need to invalidate entries when mapping dynamic regions
		 * because new table/block/page descriptors only replace old
		 * invalid descriptors, that aren't TLB cached.
		 */
		dsbishst();
	}

	if (end_pa > ctx->max_pa)
		ctx->max_pa = end_pa;
	if (end_va > ctx->max_va)
		ctx->max_va = end_va;

	return 0;
}

int mmap_add_dynamic_region(unsigned long long base_pa,
			    uintptr_t base_va, size_t size, mmap_attr_t attr)
{
	mmap_region_t mm = MAP_REGION(base_pa, base_va, size, attr);
	return mmap_add_dynamic_region_ctx(&tf_xlat_ctx, &mm);
}

/*
 * Removes the region with given base Virtual Address and size from the given
 * context.
 *
 * Returns:
 *        0: Success.
 *   EINVAL: Invalid values were used as arguments (region not found).
 *    EPERM: Tried to remove a static region.
 */
int mmap_remove_dynamic_region_ctx(xlat_ctx_t *ctx, uintptr_t base_va,
				   size_t size)
{
	mmap_region_t *mm = ctx->mmap;
	mmap_region_t *mm_last = mm + ctx->mmap_num;
	int update_max_va_needed = 0;
	int update_max_pa_needed = 0;

	/* Check sanity of mmap array. */
	assert(mm[ctx->mmap_num].size == 0);

	while (mm->size) {
		if ((mm->base_va == base_va) && (mm->size == size))
			break;
		++mm;
	}

	/* Check that the region was found */
	if (mm->size == 0)
		return -EINVAL;

	/* If the region is static it can't be removed */
	if (!(mm->attr & MT_DYNAMIC))
		return -EPERM;

	/* Check if this region is using the top VAs or PAs. */
	if ((mm->base_va + mm->size - 1) == ctx->max_va)
		update_max_va_needed = 1;
	if ((mm->base_pa + mm->size - 1) == ctx->max_pa)
		update_max_pa_needed = 1;

	/* Update the translation tables if needed */
	if (ctx->initialized) {
		xlat_tables_unmap_region(ctx, mm, 0, ctx->base_table,
					 ctx->base_table_entries,
					 ctx->base_level);
		xlat_arch_tlbi_va_sync();
	}

	/* Remove this region by moving the rest down by one place. */
	memmove(mm, mm + 1, (uintptr_t)mm_last - (uintptr_t)mm);

	/* Check if we need to update the max VAs and PAs */
	if (update_max_va_needed) {
		ctx->max_va = 0;
		mm = ctx->mmap;
		while (mm->size) {
			if ((mm->base_va + mm->size - 1) > ctx->max_va)
				ctx->max_va = mm->base_va + mm->size - 1;
			++mm;
		}
	}

	if (update_max_pa_needed) {
		ctx->max_pa = 0;
		mm = ctx->mmap;
		while (mm->size) {
			if ((mm->base_pa + mm->size - 1) > ctx->max_pa)
				ctx->max_pa = mm->base_pa + mm->size - 1;
			++mm;
		}
	}

	return 0;
}

int mmap_remove_dynamic_region(uintptr_t base_va, size_t size)
{
	return mmap_remove_dynamic_region_ctx(&tf_xlat_ctx,
					base_va, size);
}

#endif /* PLAT_XLAT_TABLES_DYNAMIC */

#if LOG_LEVEL >= LOG_LEVEL_VERBOSE

/* Print the attributes of the specified block descriptor. */
static void xlat_desc_print(const xlat_ctx_t *ctx, uint64_t desc)
{
	int mem_type_index = ATTR_INDEX_GET(desc);
	xlat_regime_t xlat_regime = ctx->xlat_regime;

	if (mem_type_index == ATTR_IWBWA_OWBWA_NTR_INDEX) {
		tf_printf("MEM");
	} else if (mem_type_index == ATTR_NON_CACHEABLE_INDEX) {
		tf_printf("NC");
	} else {
		assert(mem_type_index == ATTR_DEVICE_INDEX);
		tf_printf("DEV");
	}

	const char *priv_str = "(PRIV)";
	const char *user_str = "(USER)";

	/*
	 * Showing Privileged vs Unprivileged only makes sense for EL1&0
	 * mappings
	 */
	const char *ro_str = "-RO";
	const char *rw_str = "-RW";
	const char *no_access_str = "-NOACCESS";

	if (xlat_regime == EL3_REGIME) {
		/* For EL3, the AP[2] bit is all what matters */
		tf_printf("%s", (desc & LOWER_ATTRS(AP_RO)) ? ro_str : rw_str);
	} else {
		const char *ap_str = (desc & LOWER_ATTRS(AP_RO)) ? ro_str : rw_str;
		tf_printf("%s", ap_str);
		tf_printf("%s", priv_str);
		/*
		 * EL0 can only have the same permissions as EL1 or no
		 * permissions at all.
		 */
		tf_printf("%s",
			  (desc & LOWER_ATTRS(AP_ACCESS_UNPRIVILEGED))
			  ? ap_str : no_access_str);
		tf_printf("%s", user_str);
	}

	const char *xn_str = "-XN";
	const char *exec_str = "-EXEC";

	if (xlat_regime == EL3_REGIME) {
		/* For EL3, the XN bit is all what matters */
		tf_printf("%s", LOWER_ATTRS(XN) & desc ? xn_str : exec_str);
	} else {
		/* For EL0 and EL1, we need to know who has which rights */
		tf_printf("%s", LOWER_ATTRS(PXN) & desc ? xn_str : exec_str);
		tf_printf("%s", priv_str);

		tf_printf("%s", LOWER_ATTRS(UXN) & desc ? xn_str : exec_str);
		tf_printf("%s", user_str);
	}

	tf_printf(LOWER_ATTRS(NS) & desc ? "-NS" : "-S");
}

static const char * const level_spacers[] = {
	"[LV0] ",
	"  [LV1] ",
	"    [LV2] ",
	"      [LV3] "
};

static const char *invalid_descriptors_ommited =
		"%s(%d invalid descriptors omitted)\n";

/*
 * Recursive function that reads the translation tables passed as an argument
 * and prints their status.
 */
static void xlat_tables_print_internal(xlat_ctx_t *ctx,
		const uintptr_t table_base_va,
		uint64_t *const table_base, const int table_entries,
		const unsigned int level)
{
	assert(level <= XLAT_TABLE_LEVEL_MAX);

	uint64_t desc;
	uintptr_t table_idx_va = table_base_va;
	int table_idx = 0;

	size_t level_size = XLAT_BLOCK_SIZE(level);

	/*
	 * Keep track of how many invalid descriptors are counted in a row.
	 * Whenever multiple invalid descriptors are found, only the first one
	 * is printed, and a line is added to inform about how many descriptors
	 * have been omitted.
	 */
	int invalid_row_count = 0;

	while (table_idx < table_entries) {

		desc = table_base[table_idx];

		if ((desc & DESC_MASK) == INVALID_DESC) {

			if (invalid_row_count == 0) {
				tf_printf("%sVA:%p size:0x%zx\n",
					  level_spacers[level],
					  (void *)table_idx_va, level_size);
			}
			invalid_row_count++;

		} else {

			if (invalid_row_count > 1) {
				tf_printf(invalid_descriptors_ommited,
					  level_spacers[level],
					  invalid_row_count - 1);
			}
			invalid_row_count = 0;

			/*
			 * Check if this is a table or a block. Tables are only
			 * allowed in levels other than 3, but DESC_PAGE has the
			 * same value as DESC_TABLE, so we need to check.
			 */
			if (((desc & DESC_MASK) == TABLE_DESC) &&
					(level < XLAT_TABLE_LEVEL_MAX)) {
				/*
				 * Do not print any PA for a table descriptor,
				 * as it doesn't directly map physical memory
				 * but instead points to the next translation
				 * table in the translation table walk.
				 */
				tf_printf("%sVA:%p size:0x%zx\n",
					  level_spacers[level],
					  (void *)table_idx_va, level_size);

				uintptr_t addr_inner = desc & TABLE_ADDR_MASK;

				xlat_tables_print_internal(ctx, table_idx_va,
					(uint64_t *)addr_inner,
					XLAT_TABLE_ENTRIES, level + 1);
			} else {
				tf_printf("%sVA:%p PA:0x%llx size:0x%zx ",
					  level_spacers[level],
					  (void *)table_idx_va,
					  (unsigned long long)(desc & TABLE_ADDR_MASK),
					  level_size);
				xlat_desc_print(ctx, desc);
				tf_printf("\n");
			}
		}

		table_idx++;
		table_idx_va += level_size;
	}

	if (invalid_row_count > 1) {
		tf_printf(invalid_descriptors_ommited,
			  level_spacers[level], invalid_row_count - 1);
	}
}

#endif /* LOG_LEVEL >= LOG_LEVEL_VERBOSE */

void xlat_tables_print(xlat_ctx_t *ctx)
{
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	const char *xlat_regime_str;
	if (ctx->xlat_regime == EL1_EL0_REGIME) {
		xlat_regime_str = "1&0";
	} else {
		assert(ctx->xlat_regime == EL3_REGIME);
		xlat_regime_str = "3";
	}
	VERBOSE("Translation tables state:\n");
	VERBOSE("  Xlat regime:     EL%s\n", xlat_regime_str);
	VERBOSE("  Max allowed PA:  0x%llx\n", ctx->pa_max_address);
	VERBOSE("  Max allowed VA:  %p\n", (void *) ctx->va_max_address);
	VERBOSE("  Max mapped PA:   0x%llx\n", ctx->max_pa);
	VERBOSE("  Max mapped VA:   %p\n", (void *) ctx->max_va);

	VERBOSE("  Initial lookup level: %i\n", ctx->base_level);
	VERBOSE("  Entries @initial lookup level: %i\n",
		ctx->base_table_entries);

	int used_page_tables;
#if PLAT_XLAT_TABLES_DYNAMIC
	used_page_tables = 0;
	for (unsigned int i = 0; i < ctx->tables_num; ++i) {
		if (ctx->tables_mapped_regions[i] != 0)
			++used_page_tables;
	}
#else
	used_page_tables = ctx->next_table;
#endif
	VERBOSE("  Used %i sub-tables out of %i (spare: %i)\n",
		used_page_tables, ctx->tables_num,
		ctx->tables_num - used_page_tables);

	xlat_tables_print_internal(ctx, 0, ctx->base_table,
				   ctx->base_table_entries, ctx->base_level);
#endif /* LOG_LEVEL >= LOG_LEVEL_VERBOSE */
}

void init_xlat_tables_ctx(xlat_ctx_t *ctx)
{
	assert(ctx != NULL);
	assert(!ctx->initialized);
	assert(ctx->xlat_regime == EL3_REGIME || ctx->xlat_regime == EL1_EL0_REGIME);
	assert(!is_mmu_enabled_ctx(ctx));

	mmap_region_t *mm = ctx->mmap;

	print_mmap(mm);

	/* All tables must be zeroed before mapping any region. */

	for (unsigned int i = 0; i < ctx->base_table_entries; i++)
		ctx->base_table[i] = INVALID_DESC;

	for (unsigned int j = 0; j < ctx->tables_num; j++) {
#if PLAT_XLAT_TABLES_DYNAMIC
		ctx->tables_mapped_regions[j] = 0;
#endif
		for (unsigned int i = 0; i < XLAT_TABLE_ENTRIES; i++)
			ctx->tables[j][i] = INVALID_DESC;
	}

	while (mm->size) {
		uintptr_t end_va = xlat_tables_map_region(ctx, mm, 0, ctx->base_table,
				ctx->base_table_entries, ctx->base_level);

		if (end_va != mm->base_va + mm->size - 1) {
			ERROR("Not enough memory to map region:\n"
			      " VA:%p  PA:0x%llx  size:0x%zx  attr:0x%x\n",
			      (void *)mm->base_va, mm->base_pa, mm->size, mm->attr);
			panic();
		}

		mm++;
	}

	assert(ctx->pa_max_address <= xlat_arch_get_max_supported_pa());
	assert(ctx->max_va <= ctx->va_max_address);
	assert(ctx->max_pa <= ctx->pa_max_address);

	ctx->initialized = 1;

	xlat_tables_print(ctx);
}

void init_xlat_tables(void)
{
	init_xlat_tables_ctx(&tf_xlat_ctx);
}

/*
 * If dynamic allocation of new regions is disabled then by the time we call the
 * function enabling the MMU, we'll have registered all the memory regions to
 * map for the system's lifetime. Therefore, at this point we know the maximum
 * physical address that will ever be mapped.
 *
 * If dynamic allocation is enabled then we can't make any such assumption
 * because the maximum physical address could get pushed while adding a new
 * region. Therefore, in this case we have to assume that the whole address
 * space size might be mapped.
 */
#ifdef PLAT_XLAT_TABLES_DYNAMIC
#define MAX_PHYS_ADDR	tf_xlat_ctx.pa_max_address
#else
#define MAX_PHYS_ADDR	tf_xlat_ctx.max_pa
#endif

#ifdef AARCH32

void enable_mmu_secure(unsigned int flags)
{
	enable_mmu_arch(flags, tf_xlat_ctx.base_table, MAX_PHYS_ADDR,
			tf_xlat_ctx.va_max_address);
}

#else

void enable_mmu_el1(unsigned int flags)
{
	enable_mmu_arch(flags, tf_xlat_ctx.base_table, MAX_PHYS_ADDR,
			tf_xlat_ctx.va_max_address);
}

void enable_mmu_el3(unsigned int flags)
{
	enable_mmu_arch(flags, tf_xlat_ctx.base_table, MAX_PHYS_ADDR,
			tf_xlat_ctx.va_max_address);
}

#endif /* AARCH32 */

/*
 * Do a translation table walk to find the block or page descriptor that maps
 * virtual_addr.
 *
 * On success, return the address of the descriptor within the translation
 * table. Its lookup level is stored in '*out_level'.
 * On error, return NULL.
 *
 * xlat_table_base
 *   Base address for the initial lookup level.
 * xlat_table_base_entries
 *   Number of entries in the translation table for the initial lookup level.
 * virt_addr_space_size
 *   Size in bytes of the virtual address space.
 */
static uint64_t *find_xlat_table_entry(uintptr_t virtual_addr,
				       void *xlat_table_base,
				       int xlat_table_base_entries,
				       unsigned long long virt_addr_space_size,
				       int *out_level)
{
	unsigned int start_level;
	uint64_t *table;
	int entries;

	VERBOSE("%s(%p)\n", __func__, (void *)virtual_addr);

	start_level = GET_XLAT_TABLE_LEVEL_BASE(virt_addr_space_size);
	VERBOSE("Starting translation table walk from level %i\n", start_level);

	table = xlat_table_base;
	entries = xlat_table_base_entries;

	for (unsigned int level = start_level;
	     level <= XLAT_TABLE_LEVEL_MAX;
	     ++level) {
		int idx;
		uint64_t desc;
		uint64_t desc_type;

		VERBOSE("Table address: %p\n", (void *)table);

		idx = XLAT_TABLE_IDX(virtual_addr, level);
		VERBOSE("Index into level %i table: %i\n", level, idx);
		if (idx >= entries) {
			VERBOSE("Invalid address\n");
			return NULL;
		}

		desc = table[idx];
		desc_type = desc & DESC_MASK;
		VERBOSE("Descriptor at level %i: 0x%llx\n", level,
				(unsigned long long)desc);

		if (desc_type == INVALID_DESC) {
			VERBOSE("Invalid entry (memory not mapped)\n");
			return NULL;
		}

		if (level == XLAT_TABLE_LEVEL_MAX) {
			/*
			 * There can't be table entries at the final lookup
			 * level.
			 */
			assert(desc_type == PAGE_DESC);
			VERBOSE("Descriptor mapping a memory page (size: 0x%llx)\n",
				(unsigned long long)XLAT_BLOCK_SIZE(XLAT_TABLE_LEVEL_MAX));
			*out_level = level;
			return &table[idx];
		}

		if (desc_type == BLOCK_DESC) {
			VERBOSE("Descriptor mapping a memory block (size: 0x%llx)\n",
				(unsigned long long)XLAT_BLOCK_SIZE(level));
			*out_level = level;
			return &table[idx];
		}

		assert(desc_type == TABLE_DESC);
		VERBOSE("Table descriptor, continuing xlat table walk...\n");
		table = (uint64_t *)(uintptr_t)(desc & TABLE_ADDR_MASK);
		entries = XLAT_TABLE_ENTRIES;
	}

	/*
	 * This shouldn't be reached, the translation table walk should end at
	 * most at level XLAT_TABLE_LEVEL_MAX and return from inside the loop.
	 */
	assert(0);

	return NULL;
}


static int get_mem_attributes_internal(const xlat_ctx_t *ctx, uintptr_t base_va,
		uint32_t *attributes, uint64_t **table_entry,
		unsigned long long *addr_pa, int *table_level)
{
	uint64_t *entry;
	uint64_t desc;
	int level;
	unsigned long long virt_addr_space_size;

	/*
	 * Sanity-check arguments.
	 */
	assert(ctx != NULL);
	assert(ctx->initialized);
	assert(ctx->xlat_regime == EL1_EL0_REGIME || ctx->xlat_regime == EL3_REGIME);

	virt_addr_space_size = (unsigned long long)ctx->va_max_address + 1;
	assert(virt_addr_space_size > 0);

	entry = find_xlat_table_entry(base_va,
				ctx->base_table,
				ctx->base_table_entries,
				virt_addr_space_size,
				&level);
	if (entry == NULL) {
		WARN("Address %p is not mapped.\n", (void *)base_va);
		return -EINVAL;
	}

	if (addr_pa != NULL) {
		*addr_pa = *entry & TABLE_ADDR_MASK;
	}

	if (table_entry != NULL) {
		*table_entry = entry;
	}

	if (table_level != NULL) {
		*table_level = level;
	}

	desc = *entry;

#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
	VERBOSE("Attributes: ");
	xlat_desc_print(ctx, desc);
	tf_printf("\n");
#endif /* LOG_LEVEL >= LOG_LEVEL_VERBOSE */

	assert(attributes != NULL);
	*attributes = 0;

	int attr_index = (desc >> ATTR_INDEX_SHIFT) & ATTR_INDEX_MASK;

	if (attr_index == ATTR_IWBWA_OWBWA_NTR_INDEX) {
		*attributes |= MT_MEMORY;
	} else if (attr_index == ATTR_NON_CACHEABLE_INDEX) {
		*attributes |= MT_NON_CACHEABLE;
	} else {
		assert(attr_index == ATTR_DEVICE_INDEX);
		*attributes |= MT_DEVICE;
	}

	int ap2_bit = (desc >> AP2_SHIFT) & 1;

	if (ap2_bit == AP2_RW)
		*attributes |= MT_RW;

	if (ctx->xlat_regime == EL1_EL0_REGIME) {
		int ap1_bit = (desc >> AP1_SHIFT) & 1;
		if (ap1_bit == AP1_ACCESS_UNPRIVILEGED)
			*attributes |= MT_USER;
	}

	int ns_bit = (desc >> NS_SHIFT) & 1;

	if (ns_bit == 1)
		*attributes |= MT_NS;

	uint64_t xn_mask = xlat_arch_regime_get_xn_desc(ctx->xlat_regime);

	if ((desc & xn_mask) == xn_mask) {
		*attributes |= MT_EXECUTE_NEVER;
	} else {
		assert((desc & xn_mask) == 0);
	}

	return 0;
}


int get_mem_attributes(const xlat_ctx_t *ctx, uintptr_t base_va,
		       uint32_t *attributes)
{
	return get_mem_attributes_internal(ctx, base_va, attributes,
					   NULL, NULL, NULL);
}


int change_mem_attributes(xlat_ctx_t *ctx,
			uintptr_t base_va,
			size_t size,
			uint32_t attr)
{
	/* Note: This implementation isn't optimized. */

	assert(ctx != NULL);
	assert(ctx->initialized);

	unsigned long long virt_addr_space_size =
		(unsigned long long)ctx->va_max_address + 1;
	assert(virt_addr_space_size > 0);

	if (!IS_PAGE_ALIGNED(base_va)) {
		WARN("%s: Address %p is not aligned on a page boundary.\n",
		     __func__, (void *)base_va);
		return -EINVAL;
	}

	if (size == 0) {
		WARN("%s: Size is 0.\n", __func__);
		return -EINVAL;
	}

	if ((size % PAGE_SIZE) != 0) {
		WARN("%s: Size 0x%zx is not a multiple of a page size.\n",
		     __func__, size);
		return -EINVAL;
	}

	if (((attr & MT_EXECUTE_NEVER) == 0) && ((attr & MT_RW) != 0)) {
		WARN("%s() doesn't allow to remap memory as read-write and executable.\n",
		     __func__);
		return -EINVAL;
	}

	int pages_count = size / PAGE_SIZE;

	VERBOSE("Changing memory attributes of %i pages starting from address %p...\n",
		pages_count, (void *)base_va);

	uintptr_t base_va_original = base_va;

	/*
	 * Sanity checks.
	 */
	for (int i = 0; i < pages_count; ++i) {
		uint64_t *entry;
		uint64_t desc;
		int level;

		entry = find_xlat_table_entry(base_va,
					      ctx->base_table,
					      ctx->base_table_entries,
					      virt_addr_space_size,
					      &level);
		if (entry == NULL) {
			WARN("Address %p is not mapped.\n", (void *)base_va);
			return -EINVAL;
		}

		desc = *entry;

		/*
		 * Check that all the required pages are mapped at page
		 * granularity.
		 */
		if (((desc & DESC_MASK) != PAGE_DESC) ||
			(level != XLAT_TABLE_LEVEL_MAX)) {
			WARN("Address %p is not mapped at the right granularity.\n",
			     (void *)base_va);
			WARN("Granularity is 0x%llx, should be 0x%x.\n",
			     (unsigned long long)XLAT_BLOCK_SIZE(level), PAGE_SIZE);
			return -EINVAL;
		}

		/*
		 * If the region type is device, it shouldn't be executable.
		 */
		int attr_index = (desc >> ATTR_INDEX_SHIFT) & ATTR_INDEX_MASK;
		if (attr_index == ATTR_DEVICE_INDEX) {
			if ((attr & MT_EXECUTE_NEVER) == 0) {
				WARN("Setting device memory as executable at address %p.",
				     (void *)base_va);
				return -EINVAL;
			}
		}

		base_va += PAGE_SIZE;
	}

	/* Restore original value. */
	base_va = base_va_original;

	VERBOSE("%s: All pages are mapped, now changing their attributes...\n",
		__func__);

	for (int i = 0; i < pages_count; ++i) {

		uint32_t old_attr, new_attr;
		uint64_t *entry;
		int level;
		unsigned long long addr_pa;

		get_mem_attributes_internal(ctx, base_va, &old_attr,
					    &entry, &addr_pa, &level);

		VERBOSE("Old attributes: 0x%x\n", old_attr);

		/*
		 * From attr, only MT_RO/MT_RW, MT_EXECUTE/MT_EXECUTE_NEVER and
		 * MT_USER/MT_PRIVILEGED are taken into account. Any other
		 * information is ignored.
		 */

		/* Clean the old attributes so that they can be rebuilt. */
		new_attr = old_attr & ~(MT_RW|MT_EXECUTE_NEVER|MT_USER);

		/*
		 * Update attributes, but filter out the ones this function
		 * isn't allowed to change.
		 */
		new_attr |= attr & (MT_RW|MT_EXECUTE_NEVER|MT_USER);

		VERBOSE("New attributes: 0x%x\n", new_attr);

		/*
		 * The break-before-make sequence requires writing an invalid
		 * descriptor and making sure that the system sees the change
		 * before writing the new descriptor.
		 */
		*entry = INVALID_DESC;

		/* Invalidate any cached copy of this mapping in the TLBs. */
		xlat_arch_tlbi_va_regime(base_va, ctx->xlat_regime);

		/* Ensure completion of the invalidation. */
		xlat_arch_tlbi_va_sync();

		/* Write new descriptor */
		*entry = xlat_desc(ctx, new_attr, addr_pa, level);

		base_va += PAGE_SIZE;
	}

	/* Ensure that the last descriptor writen is seen by the system. */
	dsbish();

	return 0;
}