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allocin'g actually works now, but we can free random pointers... weird

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This commit is contained in:
Nathan Singer
2025-06-13 12:39:19 -04:00
parent a009462c72
commit 45c167568c
2 changed files with 48 additions and 34 deletions
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72
kernel/arch/pmm/pmm.c
View File

@ -49,32 +49,32 @@ void pmm_init(void);
void* pmm_alloc_block(void);
void pmm_free_block(void* p);
void __pmm_set(int bit, struct pmm_mem_info mem_block)
void __pmm_set(int bit, struct pmm_mem_info* mem_block)
{
(mem_block.bitmap)[bit / 32] |= (1 << (bit % 32));
mem_block.used_blocks++;
mem_block.free_blocks--;
(mem_block->bitmap)[bit / 32] |= (1 << (bit % 32));
mem_block->used_blocks++;
mem_block->free_blocks--;
}
void __pmm_unset(int bit, struct pmm_mem_info mem_block)
void __pmm_unset(int bit, struct pmm_mem_info* mem_block)
{
(mem_block.bitmap)[bit / 32] &= ~(1 << (bit % 32));
mem_block.used_blocks--;
mem_block.free_blocks--;
(mem_block->bitmap)[bit / 32] &= ~(1 << (bit % 32));
mem_block->used_blocks--;
mem_block->free_blocks++;
}
bool __pmm_test(int bit, struct pmm_mem_info mem_block)
bool __pmm_test(int bit, struct pmm_mem_info* mem_block)
{
return (mem_block.bitmap)[bit / 32] & (1 << (bit % 32));
return (mem_block->bitmap)[bit / 32] & (1 << (bit % 32));
}
int __pmm_first_free(struct pmm_mem_info mem_block)
int __pmm_first_free(struct pmm_mem_info* mem_block)
{
for (uint32_t i = 0; i < PMM_GET_MEM_BLOCKS(mem_block) / 32; i++) {
if (mem_block.bitmap[i] == 0xFFFFFFFF) // this segment is full
for (uint32_t i = 0; i < PMM_GET_MEM_BLOCKS((*mem_block)) / 32; i++) {
if (mem_block->bitmap[i] == 0xFFFFFFFF) // this segment is full
continue;
for (int j = 0; j < 32; j++) {
if (mem_block.bitmap[i] & (1 << j))
if (mem_block->bitmap[i] & (1 << j))
continue; // this page is used
return (i * 32) + j; // i * 32 is the chunk of 32, plus j to get to the page in the chunk
}
@ -84,29 +84,29 @@ int __pmm_first_free(struct pmm_mem_info mem_block)
void __pmm_add_mem_block(uint32_t addr, int32_t len, struct pmm_mem_info* mem_block)
{
mem_block->startaddr = addr;
mem_block->startaddr = addr; // main_mem isn't properly being set like this... TODO
mem_block->len = len;
mem_block->bitmap = 0;
}
void __pmm_init(struct pmm_mem_info mem_block)
void __pmm_init(struct pmm_mem_info* mem_block)
{
// TODO same as above
mem_block.used_blocks = 0;
mem_block.max_blocks = PMM_GET_MEM_BLOCKS(main_mem);
mem_block.free_blocks = mem_block.max_blocks;
mem_block->used_blocks = 0;
mem_block->max_blocks = PMM_GET_MEM_BLOCKS(main_mem);
mem_block->free_blocks = mem_block->max_blocks;
memset(mem_block.bitmap, 0x0, PMM_GET_MEM_BLOCKS(mem_block) / PMM_BLOCKS_PER_BYTE); // declare all memory available
memset(mem_block->bitmap, 0x0, PMM_GET_MEM_BLOCKS((*mem_block)) / PMM_BLOCKS_PER_BYTE); // declare all memory available
#ifdef __TESTING__
printf("Initialized %1 blocks of memory (%1KiB available)\n", mem_block.max_blocks, mem_block.free_blocks * 4096);
printf("Initialized %1 blocks of memory (%1KiB available)\n", mem_block->max_blocks, mem_block->free_blocks * 4096);
#endif
__pmm_set(0, mem_block); // first block must always be set
}
void* __pmm_alloc_block(struct pmm_mem_info mem_block)
void* __pmm_alloc_block(struct pmm_mem_info* mem_block)
{
if (mem_block.free_blocks == 0) {
if (mem_block->free_blocks == 0) {
kerror("OUT OF MEMORY");
return 0;
}
@ -119,13 +119,13 @@ void* __pmm_alloc_block(struct pmm_mem_info mem_block)
__pmm_set(block_in_map, mem_block);
return (void*) (mem_block.startaddr + (block_in_map * PMM_PAGE_SIZE));
return (void*) (mem_block->startaddr + (block_in_map * PMM_PAGE_SIZE));
}
void __pmm_free_block(void* p, struct pmm_mem_info mem_block)
void __pmm_free_block(void* p, struct pmm_mem_info* mem_block)
{
uint64_t* addr = (uint64_t*) &p;
int idx = ((*addr) - mem_block.startaddr) / PMM_PAGE_SIZE;
int idx = ((*addr) - mem_block->startaddr) / PMM_PAGE_SIZE;
__pmm_unset(idx, mem_block);
}
@ -142,25 +142,25 @@ void pmm_set(int bit)
*
* below is merely a temporary solution
*/
__pmm_set(bit, main_mem);
__pmm_set(bit, &main_mem);
}
void pmm_unset(int bit)
{
// TODO: same as above
__pmm_unset(bit, main_mem);
__pmm_unset(bit, &main_mem);
}
bool pmm_test(int bit)
{
// TODO: same as above
return __pmm_test(bit, main_mem);
return __pmm_test(bit, &main_mem);
}
int pmm_first_free(void) //TODO implement a free_s where it finds a series of free pages
{
// TODO: same as above
int ret = __pmm_first_free(main_mem);
int ret = __pmm_first_free(&main_mem);
if (ret == -1)
kerror("OUT OF MEMORY");
return ret;
@ -170,17 +170,23 @@ int pmm_first_free(void) //TODO implement a free_s where it finds a series of fr
void pmm_init(void)
{
// TODO same as above
__pmm_init(main_mem);
__pmm_init(&main_mem);
}
void* pmm_alloc_block(void)
{
return __pmm_alloc_block(main_mem);
#ifdef __TESTING__
printf("PMM: Alloc'd a block!\n");
#endif
return __pmm_alloc_block(&main_mem);
}
void pmm_free_block(void* p)
{
__pmm_free_block(p, main_mem);
__pmm_free_block(p, &main_mem);
#ifdef __TESTING__
puts("PMM: Free'd a block!");
#endif
}
void pmm_add_mem_block(uint32_t addr, uint32_t len)

10
kernel/kmain.c
View File

@ -16,6 +16,8 @@
#include "multiboot.h"
extern struct pmm_mem_info main_mem;
void verify_memmap(multiboot_info_t* mbd, uint32_t magic)
{
if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
@ -61,7 +63,13 @@ void _main(multiboot_info_t* mbd, uint32_t magic)
pmm_init();
print_main_mem();
pmm_alloc_block();
void* a = pmm_alloc_block();
print_main_mem();
pmm_free_block(a);
print_main_mem();