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#include <region.h>
#include <dbglog.h>
#include <frame.h>
typedef union region_descriptor {
struct {
union region_descriptor *next;
} unused_descriptor;
struct {
size_t addr, size;
union region_descriptor *next_by_size, *first_bigger;
union region_descriptor *next_by_addr;
} free;
struct {
region_info_t i;
union region_descriptor *next_by_addr;
} used;
} descriptor_t;
#define N_RESERVE_DESCRIPTORS 2 // always keep at least 3 unused descriptors
#define N_BASE_DESCRIPTORS 12 // pre-allocate memory for 12 descriptors
static descriptor_t base_descriptors[N_BASE_DESCRIPTORS];
static descriptor_t *first_unused_descriptor;
uint32_t n_unused_descriptors;
static descriptor_t *first_free_region_by_addr, *first_free_region_by_size;
static descriptor_t *first_used_region;
// ========================================================= //
// HELPER FUNCTIONS FOR THE MANIPULATION OF THE REGION LISTS //
// ========================================================= //
static void add_unused_descriptor(descriptor_t *d) {
n_unused_descriptors++;
d->unused_descriptor.next = first_unused_descriptor;
first_unused_descriptor = d;
}
static descriptor_t *get_unused_descriptor() {
descriptor_t *r = first_unused_descriptor;
if (r != 0) {
first_unused_descriptor = r->unused_descriptor.next;
n_unused_descriptors--;
}
return r;
}
static void remove_free_region(descriptor_t *d) {
if (first_free_region_by_size == d) {
first_free_region_by_size = d->free.next_by_size;
} else {
for (descriptor_t *i = first_free_region_by_size; i != 0; i = i->free.next_by_size) {
if (i->free.next_by_size == d) {
i->free.next_by_size = d->free.next_by_size;
break;
}
}
}
if (first_free_region_by_addr == d) {
first_free_region_by_addr = d->free.next_by_addr;
} else {
for (descriptor_t *i = first_free_region_by_addr; i != 0; i = i->free.next_by_addr) {
if (i->free.next_by_addr == d) {
i->free.next_by_addr = d->free.next_by_addr;
break;
}
}
}
}
static void add_free_region(descriptor_t *d) {
/*dbg_printf("Add free region 0x%p - 0x%p\n", d->free.addr, d->free.size + d->free.addr);*/
// Find position of region in address-ordered list
// Possibly concatenate free region
descriptor_t *i = first_free_region_by_addr;
if (i == 0) {
ASSERT(first_free_region_by_size == 0);
first_free_region_by_addr = first_free_region_by_size = d;
d->free.next_by_size = d->free.first_bigger = d->free.next_by_addr = 0;
return;
} else if (d->free.addr + d->free.size == i->free.addr) {
// concatenate d . i
remove_free_region(i);
d->free.size += i->free.size;
add_unused_descriptor(i);
add_free_region(d);
return;
} else if (i->free.addr > d->free.addr) {
// insert before i
d->free.next_by_addr = i;
first_free_region_by_addr = d;
} else {
while (i != 0) {
ASSERT(d->free.addr > i->free.addr);
if (i->free.addr + i->free.size == d->free.addr) {
// concatenate i . d
remove_free_region(i);
i->free.size += d->free.size;
add_unused_descriptor(d);
add_free_region(i);
return;
} else if (i->free.next_by_addr == 0) {
i->free.next_by_addr = d;
d->free.next_by_addr = 0;
break;
} else if (d->free.addr + d->free.size == i->free.next_by_addr->free.addr) {
// concatenate d . i->next_by_addr
descriptor_t *j = i->free.next_by_addr;
remove_free_region(j);
d->free.size += j->free.size;
add_unused_descriptor(j);
add_free_region(d);
return;
} else if (i->free.next_by_addr->free.addr > d->free.addr) {
// insert between i and i->next_by_addr
d->free.next_by_addr = i->free.next_by_addr;
i->free.next_by_addr = d;
break;
} else {
// continue
i = i->free.next_by_addr;
}
}
}
// Now add it in size-ordered list
i = first_free_region_by_size;
ASSERT(i != 0);
if (d->free.size <= i->free.size) {
d->free.next_by_size = i;
d->free.first_bigger = (i->free.size > d->free.size ? i : i->free.first_bigger);
first_free_region_by_size = d;
} else {
while (i != 0) {
ASSERT(d->free.size > i->free.size);
if (i->free.next_by_size == 0) {
i->free.next_by_size = d;
if (d->free.size > i->free.size) i->free.first_bigger = d;
d->free.next_by_size = 0;
d->free.first_bigger = 0;
break;
} else if (i->free.next_by_size->free.size >= d->free.size) {
i->free.next_by_size = d;
if (d->free.size > i->free.size) i->free.first_bigger = d;
d->free.next_by_size = i->free.next_by_size;
d->free.first_bigger =
(i->free.next_by_size->free.size > d->free.size
? i->free.next_by_size
: i->free.next_by_size->free.first_bigger);
break;
} else {
// continue
i = i->free.next_by_size;
}
}
}
}
static descriptor_t *find_used_region(size_t addr) {
for (descriptor_t *i = first_used_region; i != 0; i = i->used.next_by_addr) {
if (addr >= i->used.i.addr && addr < i->used.i.addr + i->used.i.size) return i;
if (i->used.i.addr > addr) break;
}
return 0;
}
static void add_used_region(descriptor_t *d) {
descriptor_t *i = first_used_region;
ASSERT(i->used.i.addr < d->used.i.addr); // first region by address is never free
while (i != 0) {
ASSERT(i->used.i.addr < d->used.i.addr);
if (i->used.next_by_addr == 0 || i->used.next_by_addr->used.i.addr > d->used.i.addr) {
d->used.next_by_addr = i->used.next_by_addr;
i->used.next_by_addr = d;
return;
} else {
i = i->used.next_by_addr;
}
}
ASSERT(false);
}
static void remove_used_region(descriptor_t *d) {
if (first_used_region == d) {
first_used_region = d->used.next_by_addr;
} else {
for (descriptor_t *i = first_used_region; i != 0; i = i->used.next_by_addr) {
if (i->used.i.addr > d->used.i.addr) break;
if (i->used.next_by_addr == d) {
i->used.next_by_addr = d->used.next_by_addr;
break;
}
}
}
}
// =============== //
// THE ACTUAL CODE //
// =============== //
void region_allocator_init(void* kernel_data_end) {
descriptor_t *u0 = &base_descriptors[0];
u0->used.i.addr = K_HIGHHALF_ADDR;
u0->used.i.size = PAGE_ALIGN_UP(kernel_data_end) - K_HIGHHALF_ADDR;
u0->used.i.type = REGION_T_KERNEL_BASE;
u0->used.i.pf = 0;
u0->used.next_by_addr = 0;
first_used_region = u0;
descriptor_t *f0 = &base_descriptors[1];
f0->free.addr = PAGE_ALIGN_UP(kernel_data_end);
f0->free.size = (LAST_KERNEL_ADDR-f0->free.addr);
f0->free.next_by_size = 0;
f0->free.first_bigger = 0;
first_free_region_by_size = first_free_region_by_addr = f0;
n_unused_descriptors = 0;
first_unused_descriptor = 0;
for (int i = 2; i < N_BASE_DESCRIPTORS; i++) {
add_unused_descriptor(&base_descriptors[i]);
}
}
static size_t region_alloc_inner(size_t size, uint32_t type, page_fault_handler_t pf, bool use_reserve) {
size = PAGE_ALIGN_UP(size);
for (descriptor_t *i = first_free_region_by_size; i != 0; i = i->free.first_bigger) {
if (i->free.size >= size) {
// region i is the one we want to allocate in
descriptor_t *x = 0;
if (i->free.size > size) {
if (n_unused_descriptors <= N_RESERVE_DESCRIPTORS && !use_reserve) {
return 0;
}
// this assert basically means that the allocation function
// is called less than N_RESERVE_DESCRIPTORS times with
// the use_reserve flag before more descriptors
// are allocated.
x = get_unused_descriptor();
ASSERT(x != 0);
x->free.size = i->free.size - size;
if (size >= 0x4000) {
x->free.addr = i->free.addr + size;
} else {
x->free.addr = i->free.addr;
i->free.addr += x->free.size;
}
}
// do the allocation
remove_free_region(i);
if (x != 0) add_free_region(x);
size_t addr = i->free.addr;
i->used.i.addr = addr;
i->used.i.size = size;
i->used.i.type = type;
i->used.i.pf = pf;
add_used_region(i);
return addr;
}
}
return 0; //No big enough block found
}
size_t region_alloc(size_t size, uint32_t type, page_fault_handler_t pf) {
if (n_unused_descriptors <= N_RESERVE_DESCRIPTORS) {
uint32_t frame = frame_alloc(1);
if (frame == 0) return 0;
size_t descriptor_region = region_alloc_inner(PAGE_SIZE, REGION_T_DESCRIPTORS, 0, true);
ASSERT(descriptor_region != 0);
int error = pd_map_page(descriptor_region, frame, 1);
if (error) {
// this can happen if we weren't able to allocate a frame for
// a new pagetable
frame_free(frame, 1);
return 0;
}
for (descriptor_t *d = (descriptor_t*)descriptor_region;
(size_t)(d+1) <= (descriptor_region + PAGE_SIZE);
d++) {
add_unused_descriptor(d);
}
}
return region_alloc_inner(size, type, pf, false);
}
region_info_t *find_region(size_t addr) {
descriptor_t *d = find_used_region(addr);
if (d == 0) return 0;
return &d->used.i;
}
void region_free(size_t addr) {
descriptor_t *d = find_used_region(addr);
if (d == 0) return;
region_info_t i = d->used.i;
remove_used_region(d);
d->free.addr = i.addr;
d->free.size = i.size;
add_free_region(d);
}
void dbg_print_region_stats() {
dbg_printf("/ Free kernel regions, by address:\n");
for (descriptor_t *d = first_free_region_by_addr; d != 0; d = d->free.next_by_addr) {
dbg_printf("| 0x%p - 0x%p\n", d->free.addr, d->free.addr + d->free.size);
ASSERT(d != d->free.next_by_addr);
}
dbg_printf("- Free kernel regions, by size:\n");
for (descriptor_t *d = first_free_region_by_size; d != 0; d = d->free.next_by_size) {
dbg_printf("| 0x%p - 0x%p\n", d->free.addr, d->free.addr + d->free.size);
ASSERT(d != d->free.next_by_size);
}
dbg_printf("- Used kernel regions:\n");
for (descriptor_t *d = first_used_region; d != 0; d = d->used.next_by_addr) {
dbg_printf("| 0x%p - 0x%p", d->used.i.addr, d->used.i.addr + d->used.i.size);
if (d->used.i.type & REGION_T_KERNEL_BASE) dbg_printf(" Kernel code & base data");
if (d->used.i.type & REGION_T_DESCRIPTORS) dbg_printf(" Region descriptors");
if (d->used.i.type & REGION_T_PAGETABLE) dbg_printf(" Mapped PD/PT");
if (d->used.i.type & REGION_T_CORE_HEAP) dbg_printf(" Core heap");
if (d->used.i.type & REGION_T_PROC_HEAP) dbg_printf(" Kernel process heap");
if (d->used.i.type & REGION_T_CACHE) dbg_printf(" Cache");
if (d->used.i.type & REGION_T_HW) dbg_printf(" Hardware");
dbg_printf("\n");
ASSERT(d != d->used.next_by_addr);
}
dbg_printf("\\\n");
}
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