diff options
Diffstat (limited to 'kernel/mm/virtual_mm/virtual_mm.c')
| -rw-r--r-- | kernel/mm/virtual_mm/virtual_mm.c | 55 |
1 files changed, 31 insertions, 24 deletions
diff --git a/kernel/mm/virtual_mm/virtual_mm.c b/kernel/mm/virtual_mm/virtual_mm.c index 3043686..f750d8d 100644 --- a/kernel/mm/virtual_mm/virtual_mm.c +++ b/kernel/mm/virtual_mm/virtual_mm.c @@ -20,6 +20,7 @@ #include <libk/stdio.h> #include <mm/physical_mm.h> #include <mm/virtual_mm.h> +#include <stdbool.h> #include <stdint.h> extern uint32_t kernel_start; @@ -30,7 +31,7 @@ uint32_t *current_page_directory = 0; /* Kernel's page directory */ uint32_t page_directory[1024] ALIGNED(4096); /* Page table for the first 4 MiB */ -uint32_t table[1024] ALIGNED(4096); +uint32_t page_table[1024] ALIGNED(4096); ALWAYS_INLINE void virtual_mm_load_page_directory(uint32_t *page_directory) @@ -62,18 +63,19 @@ void virtual_mm_initialize(void) { for (uint32_t i = 0; i < 1024; i++) - table[i] = 0; + page_table[i] = 0; /* Identity map the first 4MiB, excluding the 4th MiB * (maps 4KiB 1024 times) */ for (uint32_t i = 0; i < 1024; i++) - table[i] = PTE_FRAME(i) | PTE_PRESENT(1) | PTE_WRITABLE(1); + page_table[i] = PTE_FRAME(i) | PTE_PRESENT(1) | PTE_WRITABLE(1); for (uint32_t i = 0; i < 1024; i++) page_directory[i] = 0; uint32_t *pd_entry = &page_directory[0]; - *pd_entry = PDE_FRAME((uint32_t) table) | PDE_PRESENT(1) | PDE_WRITABLE(1); + *pd_entry + = PDE_FRAME((uint32_t) page_table) | PDE_PRESENT(1) | PDE_WRITABLE(1); virtual_mm_switch_page_directory(page_directory); virtual_mm_enable_paging(); @@ -132,23 +134,26 @@ virtual_mm_unmap_page(void *virtual_address) } void * -virtual_mm_find_free_virtual_addresses(uint32_t n) +virtual_mm_find_free_addresses(uint32_t n) { /* Skip the first page directory, we don't wanna touch the first 4MiB. */ for (uint32_t pd_index = 1; pd_index < PAGE_DIRECTORY_SIZE; pd_index++) { uint32_t starting_pd_index = pd_index; uint32_t *pd_entry = ¤t_page_directory[pd_index]; - /* Ideally, we shouldn't be allocating tables here */ - uint32_t *table = get_or_make_table(pd_entry); + uint32_t *table = 0; + + bool table_is_present = PDE_IS_PRESENT(pd_entry); + if (!table_is_present) + table = (uint32_t *) PDE_GET_TABLE(pd_entry); for (uint32_t starting_pt_index = 0; starting_pt_index < PAGE_TABLE_SIZE; starting_pt_index++) { - uint32_t *pt_entry = &table[starting_pt_index]; - if (PTE_IS_PRESENT(pt_entry)) - continue; + uint32_t count = 0; + if (table_is_present) + if (PTE_IS_PRESENT(&table[starting_pt_index])) + continue; /* We found our starting pt_entry */ - uint32_t count = 0; for (uint32_t pt_index = starting_pt_index; pt_index <= PAGE_TABLE_SIZE; pt_index++) { /* If we overflow, switch to the consecutive page directory entry */ @@ -158,22 +163,24 @@ virtual_mm_find_free_virtual_addresses(uint32_t n) return 0; /* Ran out of pd_entries */ pd_entry = ¤t_page_directory[pd_index]; - table = get_or_make_table(pd_entry); + table_is_present = PDE_IS_PRESENT(pd_entry); pt_index = 0; } - /* If page table entry is already used, break from the current loop - */ - uint32_t *pt_entry = &table[pt_index]; - if (PTE_IS_PRESENT(pt_entry)) { - /* Since we have some used address at some point between j and - * count, we can't find n consecutive free addresses in between j - * and the used block (j + count + 1) */ - starting_pt_index += count; - break; - } + if (table_is_present) { + if (PTE_IS_PRESENT(&table[pt_index])) { + /* Since we have some used address at some point between j and + * count, we can't find n consecutive free addresses in between j + * and the used block (j + count + 1) */ + starting_pt_index += count; + break; + } + + count++; + } else + count++; - if (++count == n) + if (count == n) return (void *) VIRTUAL_ADDRESS(starting_pd_index, starting_pt_index); } @@ -188,7 +195,7 @@ void * virtual_mm_alloc_pages(uint32_t n_pages) { uint32_t starting_address - = (uint32_t) virtual_mm_find_free_virtual_addresses(n_pages); + = (uint32_t) virtual_mm_find_free_addresses(n_pages); if (starting_address == 0) return 0; |