mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
229 lines
5.4 KiB
C++
229 lines
5.4 KiB
C++
/*
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* Really really *really* Q&D malloc() and free() implementations
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* just to get going. Don't ever let anyone see this shit. :^)
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*/
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#include "types.h"
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#include "kmalloc.h"
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#include "StdLib.h"
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#include "i386.h"
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#include "system.h"
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#include "Process.h"
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#include "Scheduler.h"
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#include <AK/Assertions.h>
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#define SANITIZE_KMALLOC
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typedef struct
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{
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dword start;
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dword nchunk;
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} PACKED allocation_t;
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#define CHUNK_SIZE 128
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#define POOL_SIZE (1024 * 1024)
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#define ETERNAL_BASE_PHYSICAL 0x100000
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#define ETERNAL_RANGE_SIZE 0x100000
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#define BASE_PHYSICAL 0x200000
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#define RANGE_SIZE 0x100000
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static byte alloc_map[POOL_SIZE / CHUNK_SIZE / 8];
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volatile size_t sum_alloc = 0;
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volatile size_t sum_free = POOL_SIZE;
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volatile size_t kmalloc_sum_eternal = 0;
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static byte* s_next_eternal_ptr;
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static byte* s_end_of_eternal_range;
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bool is_kmalloc_address(const void* ptr)
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{
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if (ptr >= (byte*)ETERNAL_BASE_PHYSICAL && ptr < s_next_eternal_ptr)
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return true;
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return (dword)ptr >= BASE_PHYSICAL && (dword)ptr <= (BASE_PHYSICAL + POOL_SIZE);
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}
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void kmalloc_init()
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{
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memset(&alloc_map, 0, sizeof(alloc_map));
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memset((void *)BASE_PHYSICAL, 0, POOL_SIZE);
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kmalloc_sum_eternal = 0;
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sum_alloc = 0;
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sum_free = POOL_SIZE;
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s_next_eternal_ptr = (byte*)ETERNAL_BASE_PHYSICAL;
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s_end_of_eternal_range = s_next_eternal_ptr + ETERNAL_RANGE_SIZE;
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}
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void* kmalloc_eternal(size_t size)
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{
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void* ptr = s_next_eternal_ptr;
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s_next_eternal_ptr += size;
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ASSERT(s_next_eternal_ptr < s_end_of_eternal_range);
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kmalloc_sum_eternal += size;
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return ptr;
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}
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void* kmalloc_aligned(size_t size, size_t alignment)
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{
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void* ptr = kmalloc(size + alignment + sizeof(void*));
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dword max_addr = (dword)ptr + alignment;
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void* aligned_ptr = (void*)(max_addr - (max_addr % alignment));
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((void**)aligned_ptr)[-1] = ptr;
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return aligned_ptr;
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}
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void kfree_aligned(void* ptr)
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{
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kfree(((void**)ptr)[-1]);
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}
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void* kmalloc_page_aligned(size_t size)
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{
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void* ptr = kmalloc_aligned(size, PAGE_SIZE);
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dword d = (dword)ptr;
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ASSERT((d & PAGE_MASK) == d);
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return ptr;
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}
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void* kmalloc_impl(dword size)
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{
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InterruptDisabler disabler;
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dword chunks_needed, chunks_here, first_chunk;
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dword real_size;
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dword i, j, k;
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/* We need space for the allocation_t structure at the head of the block. */
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real_size = size + sizeof(allocation_t);
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if (sum_free < real_size) {
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kprintf("%s<%u> kmalloc(): PANIC! Out of memory (sucks, dude)\nsum_free=%u, real_size=%x\n", current->name().characters(), current->pid(), sum_free, real_size);
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HANG;
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return 0L;
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}
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chunks_needed = real_size / CHUNK_SIZE;
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if( real_size % CHUNK_SIZE )
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chunks_needed++;
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chunks_here = 0;
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first_chunk = 0;
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for( i = 0; i < (POOL_SIZE / CHUNK_SIZE / 8); ++i )
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{
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if (alloc_map[i] == 0xff) {
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// Skip over completely full bucket.
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chunks_here = 0;
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continue;
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}
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// FIXME: This scan can be optimized further with LZCNT.
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for( j = 0; j < 8; ++j )
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{
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if( !(alloc_map[i] & (1<<j)) )
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{
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if( chunks_here == 0 )
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{
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/* Mark where potential allocation starts. */
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first_chunk = i * 8 + j;
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}
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chunks_here++;
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if( chunks_here == chunks_needed )
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{
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auto* a = (allocation_t *)(BASE_PHYSICAL + (first_chunk * CHUNK_SIZE));
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byte *ptr = (byte *)a;
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ptr += sizeof(allocation_t);
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a->nchunk = chunks_needed;
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a->start = first_chunk;
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for( k = first_chunk; k < (first_chunk + chunks_needed); ++k )
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{
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alloc_map[k / 8] |= 1 << (k % 8);
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}
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sum_alloc += a->nchunk * CHUNK_SIZE;
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sum_free -= a->nchunk * CHUNK_SIZE;
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#ifdef SANITIZE_KMALLOC
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memset(ptr, 0xbb, (a->nchunk * CHUNK_SIZE) - sizeof(allocation_t));
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#endif
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return ptr;
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}
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}
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else
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{
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/* This is in use, so restart chunks_here counter. */
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chunks_here = 0;
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}
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}
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}
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kprintf("%s<%u> kmalloc(): PANIC! Out of memory (no suitable block for size %u)\n", current->name().characters(), current->pid(), size);
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HANG;
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return nullptr;
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}
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void kfree(void *ptr)
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{
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if( !ptr )
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return;
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InterruptDisabler disabler;
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allocation_t *a = (allocation_t *)((((byte *)ptr) - sizeof(allocation_t)));
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#if 0
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dword hdr = (dword)a;
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dword mhdr = hdr & ~0x7;
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kprintf("hdr / mhdr %p / %p\n", hdr, mhdr);
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ASSERT(hdr == mhdr);
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#endif
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for (dword k = a->start; k < (a->start + a->nchunk); ++k) {
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alloc_map[k / 8] &= ~(1 << (k % 8));
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}
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sum_alloc -= a->nchunk * CHUNK_SIZE;
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sum_free += a->nchunk * CHUNK_SIZE;
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#ifdef SANITIZE_KMALLOC
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memset(a, 0xaa, a->nchunk * CHUNK_SIZE);
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#endif
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}
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void* operator new(size_t size)
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{
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return kmalloc(size);
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}
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void* operator new[](size_t size)
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{
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return kmalloc(size);
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}
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void operator delete(void* ptr)
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{
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return kfree(ptr);
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}
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void operator delete[](void* ptr)
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{
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return kfree(ptr);
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}
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void operator delete(void* ptr, unsigned int)
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{
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return kfree(ptr);
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}
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void operator delete[](void* ptr, unsigned int)
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{
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return kfree(ptr);
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}
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