-/**
- * @file dmm.c
- * @author Lunaixsky
- * @brief Dynamic memory manager dedicated to kernel heap. Using implicit free
- * list implementation. This is designed to be portable, so it can serve as
- * syscalls to malloc/free in the c std lib.
- *
- * This version of code is however the simplest and yet insecured,
- * it just to demonstrate how the malloc/free works behind the stage
- *
- * @version 0.2
- * @date 2022-03-3
- *
- * @copyright Copyright (c) Lunaixsky 2022
- *
- */
-
-#include <lunaix/mm/dmm.h>
-#include <lunaix/mm/page.h>
+#include <lunaix/mm/mmap.h>
#include <lunaix/mm/vmm.h>
+#include <lunaix/process.h>
+#include <lunaix/status.h>
-#include <lunaix/constants.h>
#include <lunaix/spike.h>
-
-#define M_ALLOCATED 0x1
-#define M_PREV_FREE 0x2
-
-#define M_NOT_ALLOCATED 0x0
-#define M_PREV_ALLOCATED 0x0
-
-#define CHUNK_S(header) ((header) & ~0x3)
-#define CHUNK_PF(header) ((header)&M_PREV_FREE)
-#define CHUNK_A(header) ((header)&M_ALLOCATED)
-
-#define PACK(size, flags) (((size) & ~0x3) | (flags))
-
-#define SW(p, w) (*((uint32_t*)(p)) = w)
-#define LW(p) (*((uint32_t*)(p)))
-
-#define HPTR(bp) ((uint32_t*)(bp)-1)
-#define BPTR(bp) ((uint8_t*)(bp) + WSIZE)
-#define FPTR(hp, size) ((uint32_t*)(hp + size - WSIZE))
-#define NEXT_CHK(hp) ((uint8_t*)(hp) + CHUNK_S(LW(hp)))
-
-#define BOUNDARY 4
-#define WSIZE 4
-
-void*
-coalesce(uint8_t* chunk_ptr);
-
-void*
-lx_grow_heap(heap_context_t* heap, size_t sz);
+#include <lunaix/syscall.h>
+#include <lunaix/syscall_utils.h>
void
-place_chunk(uint8_t* ptr, size_t size);
-
-int
-dmm_init(heap_context_t* heap)
+__heap_copied(struct mm_region* region)
{
- assert((uintptr_t)heap->start % BOUNDARY == 0);
-
- heap->brk = heap->start;
-
- vmm_alloc_page(heap->brk, PG_PREM_RW);
-
- SW(heap->start, PACK(4, M_ALLOCATED));
- SW(heap->start + WSIZE, PACK(0, M_ALLOCATED));
- heap->brk += WSIZE;
-
- return lx_grow_heap(heap, HEAP_INIT_SIZE) != NULL;
+ mm_index((void**)®ion->proc_vms->heap, region);
}
int
-lxsbrk(heap_context_t* heap, void* addr)
-{
- return lxbrk(heap, addr - heap->brk) != NULL;
-}
-
-void*
-lxbrk(heap_context_t* heap, size_t size)
+create_heap(struct proc_mm* pvms, ptr_t addr)
{
- if (size == 0) {
- return heap->brk;
+ struct mmap_param map_param = { .pvms = pvms,
+ .vms_mnt = VMS_SELF,
+ .flags = MAP_ANON | MAP_PRIVATE,
+ .type = REGION_TYPE_HEAP,
+ .proct = PROT_READ | PROT_WRITE,
+ .mlen = PAGE_SIZE };
+ int status = 0;
+ struct mm_region* heap;
+ if ((status = mmap_user(NULL, &heap, addr, NULL, &map_param))) {
+ return status;
}
- // The upper bound of our next brk of heap given the size.
- // This will be used to calculate the page we need to allocate.
- // The "+ WSIZE" capture the overhead for epilogue marker
- void* next = heap->brk + ROUNDUP(size + WSIZE, WSIZE);
+ heap->region_copied = __heap_copied;
+ mm_index((void**)&pvms->heap, heap);
- if ((uintptr_t)next >= K_STACK_START) {
- return NULL;
- }
-
- uintptr_t heap_top_pg = PG_ALIGN(heap->brk);
- if (heap_top_pg != PG_ALIGN(next)) {
- // if next do require new pages to be allocated
- if (!vmm_alloc_pages((void*)(heap_top_pg + PG_SIZE),
- ROUNDUP(size, PG_SIZE),
- PG_PREM_RW)) {
- return NULL;
- }
- }
-
- void* old = heap->brk;
- heap->brk += size;
- return old;
+ return status;
}
-void*
-lx_grow_heap(heap_context_t* heap, size_t sz)
+__DEFINE_LXSYSCALL1(void*, sbrk, ssize_t, incr)
{
- void* start;
+ struct proc_mm* pvms = vmspace(__current);
+ struct mm_region* heap = pvms->heap;
- if (!(start = lxbrk(heap, sz))) {
- return NULL;
+ assert(heap);
+ int err = mem_adjust_inplace(&pvms->regions, heap, heap->end + incr);
+ if (err) {
+ return (void*)__ptr(DO_STATUS(err));
}
- sz = ROUNDUP(sz, BOUNDARY);
-
- uint32_t old_marker = *((uint32_t*)start);
- uint32_t free_hdr = PACK(sz, CHUNK_PF(old_marker));
- SW(start, free_hdr);
- SW(FPTR(start, sz), free_hdr);
- SW(NEXT_CHK(start), PACK(0, M_ALLOCATED | M_PREV_FREE));
-
- return coalesce(start);
+ return (void*)heap->end;
}
-void*
-lx_malloc(heap_context_t* heap, size_t size)
+__DEFINE_LXSYSCALL1(int, brk, void*, addr)
{
- // Simplest first fit approach.
-
- uint8_t* ptr = heap->start;
- // round to largest 4B aligned value
- // and space for header
- size = ROUNDUP(size, BOUNDARY) + WSIZE;
- while (ptr < (uint8_t*)heap->brk) {
- uint32_t header = *((uint32_t*)ptr);
- size_t chunk_size = CHUNK_S(header);
- if (chunk_size >= size && !CHUNK_A(header)) {
- // found!
- place_chunk(ptr, size);
- return BPTR(ptr);
- }
- ptr += chunk_size;
- }
-
- // if heap is full (seems to be!), then allocate more space (if it's
- // okay...)
- if ((ptr = lx_grow_heap(heap, size))) {
- place_chunk(ptr, size);
- return BPTR(ptr);
- }
-
- // Well, we are officially OOM!
- return NULL;
-}
-
-void
-place_chunk(uint8_t* ptr, size_t size)
-{
- uint32_t header = *((uint32_t*)ptr);
- size_t chunk_size = CHUNK_S(header);
- *((uint32_t*)ptr) = PACK(size, CHUNK_PF(header) | M_ALLOCATED);
- uint8_t* n_hdrptr = (uint8_t*)(ptr + size);
- uint32_t diff = chunk_size - size;
- if (!diff) {
- // if the current free block is fully occupied
- uint32_t n_hdr = LW(n_hdrptr);
- // notify the next block about our avaliability
- SW(n_hdrptr, n_hdr & ~0x2);
- } else {
- // if there is remaining free space left
- uint32_t remainder_hdr = PACK(diff, M_NOT_ALLOCATED | M_PREV_ALLOCATED);
- SW(n_hdrptr, remainder_hdr);
- SW(FPTR(n_hdrptr, diff), remainder_hdr);
-
- coalesce(n_hdrptr);
- }
-}
-
-void
-lx_free(void* ptr)
-{
- if (!ptr) {
- return;
- }
-
- uint8_t* chunk_ptr = (uint8_t*)ptr - WSIZE;
- uint32_t hdr = LW(chunk_ptr);
- size_t sz = CHUNK_S(hdr);
- uint8_t* next_hdr = chunk_ptr + sz;
-
- // make sure the ptr we are 'bout to free makes sense
- // the size trick comes from:
- // https://sourceware.org/git/?p=glibc.git;a=blob;f=malloc/malloc.c;h=1a1ac1d8f05b6f9bf295d7fdd0f12c2e4650a33c;hb=HEAD#l4437
- assert_msg(((uintptr_t)ptr < (uintptr_t)(-sz)) && !((uintptr_t)ptr & ~0x3),
- "free(): invalid pointer");
- assert_msg(sz > WSIZE && (sz & ~0x3),
- "free(): invalid size");
-
- SW(chunk_ptr, hdr & ~M_ALLOCATED);
- SW(FPTR(chunk_ptr, sz), hdr & ~M_ALLOCATED);
- SW(next_hdr, LW(next_hdr) | M_PREV_FREE);
-
- coalesce(chunk_ptr);
-}
-
-void*
-coalesce(uint8_t* chunk_ptr)
-{
- uint32_t hdr = LW(chunk_ptr);
- uint32_t pf = CHUNK_PF(hdr);
- uint32_t sz = CHUNK_S(hdr);
-
- uint32_t n_hdr = LW(chunk_ptr + sz);
+ struct proc_mm* pvms = vmspace(__current);
+ struct mm_region* heap = pvms->heap;
- if (CHUNK_A(n_hdr) && pf) {
- // case 1: prev is free
- uint32_t prev_ftr = LW(chunk_ptr - WSIZE);
- size_t prev_chunk_sz = CHUNK_S(prev_ftr);
- uint32_t new_hdr = PACK(prev_chunk_sz + sz, CHUNK_PF(prev_ftr));
- SW(chunk_ptr - prev_chunk_sz, new_hdr);
- SW(FPTR(chunk_ptr, sz), new_hdr);
- chunk_ptr -= prev_chunk_sz;
- } else if (!CHUNK_A(n_hdr) && !pf) {
- // case 2: next is free
- size_t next_chunk_sz = CHUNK_S(n_hdr);
- uint32_t new_hdr = PACK(next_chunk_sz + sz, pf);
- SW(chunk_ptr, new_hdr);
- SW(FPTR(chunk_ptr, sz + next_chunk_sz), new_hdr);
- } else if (!CHUNK_A(n_hdr) && pf) {
- // case 3: both free
- uint32_t prev_ftr = LW(chunk_ptr - WSIZE);
- size_t next_chunk_sz = CHUNK_S(n_hdr);
- size_t prev_chunk_sz = CHUNK_S(prev_ftr);
- uint32_t new_hdr =
- PACK(next_chunk_sz + prev_chunk_sz + sz, CHUNK_PF(prev_ftr));
- SW(chunk_ptr - prev_chunk_sz, new_hdr);
- SW(FPTR(chunk_ptr, sz + next_chunk_sz), new_hdr);
- chunk_ptr -= prev_chunk_sz;
+ if (!heap) {
+ return DO_STATUS(create_heap(pvms, (ptr_t)addr));
}
- // case 4: prev and next are not free
- return chunk_ptr;
+ assert(heap);
+ int err = mem_adjust_inplace(&pvms->regions, heap, (ptr_t)addr);
+ return DO_STATUS(err);
}
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / blobdiff