BOOT_CODE static bool_t
create_untypeds_for_region(
cap_t root_cnode_cap,
region_t reg,
slot_pos_t first_untyped_slot
)
{
uint32_t align_bits;
uint32_t size_bits;
while (!is_reg_empty(reg)) {
/* Determine the maximum size of the region */
size_bits = WORD_BITS - 1 - boot_clz(reg.end - reg.start);
/* Determine the alignment of the region */
align_bits = boot_ctz(reg.start);
/* Reduce size bits to align if needed */
if (align_bits < size_bits) {
size_bits = align_bits;
}
assert(size_bits >= WORD_BITS / 8);
if (!provide_untyped_cap(root_cnode_cap, reg.start, size_bits, first_untyped_slot)) {
return false;
}
reg.start += BIT(size_bits);
}
return true;
}
BOOT_CODE bool_t
create_untypeds_for_region(
cap_t root_cnode_cap,
bool_t deviceMemory,
region_t reg,
slot_pos_t first_untyped_slot
)
{
word_t align_bits;
word_t size_bits;
while (!is_reg_empty(reg)) {
/* Due to a limitation on the mdb we cannot give out an untyped to the
* the start of the kernel region. The reason for this is that cte pointers
* in mdb nodes are stored with the high bits masked out. To recreate a cte pointer
* we then need to put the high bits back in after reading it out. HOWEVER, we
* still need a way to store and identify a NULL pointer. This means reserving
* the bottom address as the 'null' address so that no one creates an cnode
* there resulting in a 'null' (yet valid) cte
*/
if (!deviceMemory && reg.start == kernelBase) {
reg.start += BIT(PAGE_BITS);
}
/* Determine the maximum size of the region */
size_bits = WORD_BITS - 1 - boot_clzl(reg.end - reg.start);
/* Determine the alignment of the region */
align_bits = boot_ctzl(reg.start);
/* Reduce size bits to align if needed */
if (align_bits < size_bits) {
size_bits = align_bits;
}
assert(size_bits >= WORD_BITS / 8);
if (!provide_untyped_cap(root_cnode_cap, deviceMemory, reg.start, size_bits, first_untyped_slot)) {
return false;
}
reg.start += BIT(size_bits);
}
return true;
}
