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#include <kernel/arch/generic.h>
#include <kernel/mem/alloc.h>
#include <kernel/util.h>
#include <stdint.h>
#define MALLOC_MAGIC 0xACAB1312
static void *highest_page;
static int malloc_balance = 0;
void mem_init(struct kmain_info *info) {
// finds the highest used page, and starts allocating pages above it
void *highest = &_bss_end;
if (highest < info->init.at + info->init.size)
highest = info->init.at + info->init.size;
// align up to PAGE_SIZE
highest_page = (void*)(((uintptr_t)highest + PAGE_MASK) & ~PAGE_MASK);
}
void mem_debugprint(void) {
tty_const("malloc balance: ");
_tty_var(malloc_balance);
tty_const(" ");
}
void *page_alloc(size_t pages) {
void *bottom = highest_page;
highest_page += pages * PAGE_SIZE;
return bottom;
}
// frees `pages` consecutive pages starting from *first
void page_free(void *first, size_t pages) {
// not implemented
}
void *kmalloc(size_t len) {
void *addr;
len += sizeof(uint32_t); // add space for MALLOC_MAGIC
// extremely inefficient, but this is only temporary anyways
addr = page_alloc(len / PAGE_SIZE + 1);
*(uint32_t*)addr = MALLOC_MAGIC;
malloc_balance++;
return addr + sizeof(uint32_t);
}
void kfree(void *ptr) {
uint32_t *magic = &((uint32_t*)ptr)[-1];
if (ptr == NULL) return;
if (*magic != MALLOC_MAGIC) {
// TODO add some kind of separate system log
tty_const("WARNING kfree() didn't find MALLOC_MAGIC, ptr == ");
_tty_var(ptr);
tty_const(" ");
} else {
// change the magic marker to detect double frees
*magic = 0xBADF2EED;
}
malloc_balance--;
}
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