implements a physical memory manager... sort of, it gives an out of mem error, and variable are setting incorrectly

This commit is contained in:
2025-06-11 20:36:30 -04:00
parent 98f8a0dc88
commit 7669ea32a4
4 changed files with 155 additions and 14 deletions

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@ -1,4 +1,10 @@
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#ifdef __TESTING__
#include <stdio.h>
#endif
#include <kernel/_kernel.h>
#include <kernel/pmm.h>
@ -19,25 +25,47 @@
*/
#define PMM_PAGE_SIZE 4096
#define PMM_BLOCKS_PER_BYTE 8
struct pmm_mem_info {
uint64_t startaddr;
uint64_t len; // in kb
uint32_t startaddr;
uint32_t len; // in kb
uint32_t* bitmap;
uint32_t max_blocks;
uint32_t free_blocks;
uint32_t used_blocks;
};
#define PMM_GET_MEM_BLOCKS(x) x.len / PMM_PAGE_SIZE
struct pmm_mem_info main_mem;
void __pmm_set(int bit, uint32_t* bitmap)
void pmm_set(int bit);
void pmm_unset(int bit);
bool pmm_test(int bit);
int pmm_first_free(void);
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)
{
bitmap[bit / 32] |= (1 << (bit % 32));
(mem_block.bitmap)[bit / 32] |= (1 << (bit % 32));
mem_block.used_blocks++;
mem_block.free_blocks--;
}
void __pmm_unset(int bit, uint32_t* bitmap)
void __pmm_unset(int bit, struct pmm_mem_info mem_block)
{
bitmap[bit / 32] &= ~(1 << (bit % 32));
(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)
{
return (mem_block.bitmap)[bit / 32] & (1 << (bit % 32));
}
int __pmm_first_free(struct pmm_mem_info mem_block)
@ -51,10 +79,57 @@ int __pmm_first_free(struct pmm_mem_info mem_block)
return (i * 32) + j; // i * 32 is the chunk of 32, plus j to get to the page in the chunk
}
}
kwarn("OUT OF MEMORY");
return -1;
}
void __pmm_add_mem_block(uint32_t addr, int32_t len, struct pmm_mem_info* mem_block)
{
mem_block->startaddr = addr;
mem_block->len = len;
mem_block->bitmap = 0;
}
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;
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);
#endif
__pmm_set(0, mem_block); // first block must always be set
}
void* __pmm_alloc_block(struct pmm_mem_info mem_block)
{
if (mem_block.free_blocks == 0) {
kerror("OUT OF MEMORY");
return 0;
}
int block_in_map = pmm_first_free();
if (block_in_map == -1) {
kerror("OUT OF MEMORY");
return 0;
}
__pmm_set(block_in_map, mem_block);
return (void*) (mem_block.startaddr + (block_in_map * PMM_PAGE_SIZE));
}
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;
__pmm_unset(idx, mem_block);
}
void pmm_set(int bit)
{
/**
@ -67,11 +142,58 @@ void pmm_set(int bit)
*
* below is merely a temporary solution
*/
__pmm_set(bit, main_mem.bitmap);
__pmm_set(bit, main_mem);
}
void pmm_unset(int bit)
{
// TODO: same as above
__pmm_unset(bit, main_mem.bitmap);
__pmm_unset(bit, main_mem);
}
bool pmm_test(int bit)
{
// TODO: same as above
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);
if (ret == -1)
kerror("OUT OF MEMORY");
return ret;
}
void pmm_init(void)
{
// TODO same as above
__pmm_init(main_mem);
}
void* pmm_alloc_block(void)
{
return __pmm_alloc_block(main_mem);
}
void pmm_free_block(void* p)
{
__pmm_free_block(p, main_mem);
}
void pmm_add_mem_block(uint32_t addr, uint32_t len)
{
// TODO: make this add to a linked list
__pmm_add_mem_block(addr, len, &main_mem);
}
#ifdef __TESTING__
void print_main_mem()
{
printf("Available blocks: %1\nUsed blocks: %1\nMax blocks: %1\n",
main_mem.free_blocks, main_mem.used_blocks, main_mem.max_blocks);
}
#endif

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@ -1,4 +1,15 @@
#include <stdint.h>
#ifndef ARCH_PMM_H
#define ARCH_PMM_H
void pmm_init(void);
void* pmm_alloc_block(void);
void pmm_free_block(void* p);
void pmm_add_mem_block(uint32_t addr, uint32_t len);
#ifdef __TESTING__
void print_main_mem();
#endif
#endif

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@ -35,8 +35,9 @@ void verify_memmap(multiboot_info_t* mbd, uint32_t magic)
printf("Start Addr: %4 | Length: %4 | Size: %2 | Type: %d\n",
mmmt->addr, mmmt->len, mmmt->size, mmmt->type);
// mmmt-> len is in bytes (according to multiboot specification0
// mmmt->len / 1024 == kib // block size == blocks
if (mmmt->addr == 0x100000) {
pmm_add_mem_block((uint32_t) mmmt->addr, (uint32_t) mmmt->len);
}
}
}
@ -57,6 +58,13 @@ void _main(multiboot_info_t* mbd, uint32_t magic)
serial_initialize();
#endif
pmm_init();
print_main_mem();
pmm_alloc_block();
print_main_mem();
//setup_paging();
init_kb();

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@ -115,8 +115,8 @@ int printf(const char* restrict format, ...) {
written += len;
} else if (*format == '1') {
format++;
int32_t i = (int32_t) va_arg(parameters, int32_t);
s32toa(i, buffer, 10);
int32_t i = (uint32_t) va_arg(parameters, int32_t);
u32toa(i, buffer, 10);
size_t len = strlen(buffer);
if (maxrem < len) {
// TODO: Set errno to EOVERFLOW.