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/*
* Really really *really* Q&D malloc() and free() implementations
* just to get going. Don't ever let anyone see this shit. :^)
*/
#include <AK/Assertions.h>
#include <AK/Types.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/KSyms.h>
#include <Kernel/Process.h>
#include <Kernel/Scheduler.h>
#include <Kernel/StdLib.h>
#include <Kernel/kmalloc.h>
#define SANITIZE_KMALLOC
struct [[gnu::packed]] allocation_t
{
size_t start;
size_t nchunk;
};
#define CHUNK_SIZE 32
#define POOL_SIZE (1024 * 1024)
#define ETERNAL_BASE_PHYSICAL (1 * MB)
#define ETERNAL_RANGE_SIZE (2 * MB)
#define BASE_PHYSICAL (3 * MB)
#define RANGE_SIZE (1 * MB)
static u8 alloc_map[POOL_SIZE / CHUNK_SIZE / 8];
volatile size_t sum_alloc = 0;
volatile size_t sum_free = POOL_SIZE;
volatile size_t kmalloc_sum_eternal = 0;
u32 g_kmalloc_call_count;
u32 g_kfree_call_count;
bool g_dump_kmalloc_stacks;
static u8* s_next_eternal_ptr;
static u8* s_end_of_eternal_range;
bool is_kmalloc_address(const void* ptr)
{
if (ptr >= (u8*)ETERNAL_BASE_PHYSICAL && ptr < s_next_eternal_ptr)
return true;
return (size_t)ptr >= BASE_PHYSICAL && (size_t)ptr <= (BASE_PHYSICAL + POOL_SIZE);
}
void kmalloc_init()
{
memset(&alloc_map, 0, sizeof(alloc_map));
memset((void*)BASE_PHYSICAL, 0, POOL_SIZE);
kmalloc_sum_eternal = 0;
sum_alloc = 0;
sum_free = POOL_SIZE;
s_next_eternal_ptr = (u8*)ETERNAL_BASE_PHYSICAL;
s_end_of_eternal_range = s_next_eternal_ptr + ETERNAL_RANGE_SIZE;
}
void* kmalloc_eternal(size_t size)
{
void* ptr = s_next_eternal_ptr;
s_next_eternal_ptr += size;
ASSERT(s_next_eternal_ptr < s_end_of_eternal_range);
kmalloc_sum_eternal += size;
return ptr;
}
void* kmalloc_aligned(size_t size, size_t alignment)
{
void* ptr = kmalloc(size + alignment + sizeof(void*));
size_t max_addr = (size_t)ptr + alignment;
void* aligned_ptr = (void*)(max_addr - (max_addr % alignment));
((void**)aligned_ptr)[-1] = ptr;
return aligned_ptr;
}
void kfree_aligned(void* ptr)
{
kfree(((void**)ptr)[-1]);
}
void* kmalloc_page_aligned(size_t size)
{
void* ptr = kmalloc_aligned(size, PAGE_SIZE);
size_t d = (size_t)ptr;
ASSERT((d & PAGE_MASK) == d);
return ptr;
}
void* kmalloc_impl(size_t size)
{
InterruptDisabler disabler;
++g_kmalloc_call_count;
if (g_dump_kmalloc_stacks && ksyms_ready) {
dbgprintf("kmalloc(%u)\n", size);
dump_backtrace();
}
// We need space for the allocation_t structure at the head of the block.
size_t real_size = size + sizeof(allocation_t);
if (sum_free < real_size) {
dump_backtrace();
kprintf("%s(%u) kmalloc(): PANIC! Out of memory (sucks, dude)\nsum_free=%u, real_size=%u\n", current->process().name().characters(), current->pid(), sum_free, real_size);
hang();
}
size_t chunks_needed = real_size / CHUNK_SIZE;
if (real_size % CHUNK_SIZE)
++chunks_needed;
size_t chunks_here = 0;
size_t first_chunk = 0;
for (size_t i = 0; i < (POOL_SIZE / CHUNK_SIZE / 8); ++i) {
if (alloc_map[i] == 0xff) {
// Skip over completely full bucket.
chunks_here = 0;
continue;
}
// FIXME: This scan can be optimized further with LZCNT.
for (size_t j = 0; j < 8; ++j) {
if (!(alloc_map[i] & (1 << j))) {
if (chunks_here == 0) {
// Mark where potential allocation starts.
first_chunk = i * 8 + j;
}
++chunks_here;
if (chunks_here == chunks_needed) {
auto* a = (allocation_t*)(BASE_PHYSICAL + (first_chunk * CHUNK_SIZE));
u8* ptr = (u8*)a;
ptr += sizeof(allocation_t);
a->nchunk = chunks_needed;
a->start = first_chunk;
for (size_t k = first_chunk; k < (first_chunk + chunks_needed); ++k) {
alloc_map[k / 8] |= 1 << (k % 8);
}
sum_alloc += a->nchunk * CHUNK_SIZE;
sum_free -= a->nchunk * CHUNK_SIZE;
#ifdef SANITIZE_KMALLOC
memset(ptr, 0xbb, (a->nchunk * CHUNK_SIZE) - sizeof(allocation_t));
#endif
return ptr;
}
} else {
// This is in use, so restart chunks_here counter.
chunks_here = 0;
}
}
}
kprintf("%s(%u) kmalloc(): PANIC! Out of memory (no suitable block for size %u)\n", current->process().name().characters(), current->pid(), size);
dump_backtrace();
hang();
}
void kfree(void* ptr)
{
if (!ptr)
return;
InterruptDisabler disabler;
++g_kfree_call_count;
auto* a = (allocation_t*)((((u8*)ptr) - sizeof(allocation_t)));
for (size_t k = a->start; k < (a->start + a->nchunk); ++k)
alloc_map[k / 8] &= ~(1 << (k % 8));
sum_alloc -= a->nchunk * CHUNK_SIZE;
sum_free += a->nchunk * CHUNK_SIZE;
#ifdef SANITIZE_KMALLOC
memset(a, 0xaa, a->nchunk * CHUNK_SIZE);
#endif
}
void* operator new(size_t size)
{
return kmalloc(size);
}
void* operator new[](size_t size)
{
return kmalloc(size);
}
void operator delete(void* ptr)
{
return kfree(ptr);
}
void operator delete[](void* ptr)
{
return kfree(ptr);
}
void operator delete(void* ptr, size_t)
{
return kfree(ptr);
}
void operator delete[](void* ptr, size_t)
{
return kfree(ptr);
}
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