diff options
Diffstat (limited to 'kernel/l0/region.c')
| -rw-r--r-- | kernel/l0/region.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/kernel/l0/region.c b/kernel/l0/region.c new file mode 100644 index 0000000..421a018 --- /dev/null +++ b/kernel/l0/region.c @@ -0,0 +1,293 @@ +#include <region.h> +#include <dbglog.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_BASE_DESCRIPTORS 12 // pre-allocate memory for 12 descriptors +static descriptor_t base_descriptors[N_BASE_DESCRIPTORS]; + +static descriptor_t *first_unused_descriptor; +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) { + 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; + 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 = (0xFFFFF000-f0->free.addr); // last page cannot be used... + f0->free.next_by_size = 0; + f0->free.first_bigger = 0; + first_free_region_by_size = first_free_region_by_addr = f0; + + first_unused_descriptor = 0; + for (int i = 2; i < N_BASE_DESCRIPTORS; i++) { + add_unused_descriptor(&base_descriptors[i]); + } +} + +size_t region_alloc(size_t size, uint32_t type, page_fault_handler_t pf) { + 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) { + remove_free_region(i); + if (i->free.size > size) { + descriptor_t *x = get_unused_descriptor(); + if (x == 0) { + return 0; + // TODO: allocate more descriptors + } + 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; + } + 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; //Not found +} + +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_PAGEDIR) dbg_printf(" Mapped page directory"); + if (d->used.i.type & REGION_T_PAGETABLE) dbg_printf(" Mapped page table"); + 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"); +} |