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feat: implemented liballoc for proper malloc

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This commit is contained in:
Rick Rongen
2021-02-27 13:19:14 +01:00
parent 9f72d4bb1a
commit 9fdc89a3a6
6 changed files with 825 additions and 80 deletions
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884
kernel/mem/malloc.c
View File

@@ -7,84 +7,824 @@
#include "malloc.h"
#include "pmm.h"
#define MALLOC_TYPE_FREE 0
#define MALLOC_TYPE_USED 1
// retrieved from https://github.com/blanham/liballoc
int malloc_entries = 0;
int malloc_used = 0;
typedef struct malloc_map {
struct malloc_map *next;
struct malloc_map *prev;
uint32_t size;
int type;
} malloc_map;
malloc_map *first_malloc_entry;
void malloc_init() {
first_malloc_entry = pmm_get_pages(16);
first_malloc_entry->next = first_malloc_entry;
first_malloc_entry->prev = first_malloc_entry;
first_malloc_entry->size = PAGE_SIZE * 16;
first_malloc_entry->type = MALLOC_TYPE_FREE;
malloc_entries++;
}
void split_malloc_map(malloc_map *entry, unsigned int size) {
malloc_entries++;
malloc_map *new_entry = entry + sizeof(malloc_map) + size;
new_entry->size = entry->size - size - sizeof(malloc_map);
new_entry->next = entry->next;
new_entry->prev = entry;
new_entry->type = MALLOC_TYPE_FREE;
entry->next->prev = new_entry;
entry->next = new_entry;
entry->size = size;
}
void *malloc(size_t size) {
// todo replace this horrible mess!
// this lacks any page alignment and what so ever
void* result = NULL;
/** This function is supposed to lock the memory data structures. It
* could be as simple as disabling interrupts or acquiring a spinlock.
* It's up to you to decide.
*
* \return 0 if the lock was acquired successfully. Anything else is
* failure.
*/
int liballoc_lock() {
task_lock_acquire();
malloc_map *current_map = first_malloc_entry;
// iterate through maps
do {
if (current_map->type == MALLOC_TYPE_USED) {
goto malloc_find_next;
}
if ((unsigned int) current_map->size < size) {
goto malloc_find_next;
}
if ((unsigned int) current_map->size > (size + sizeof(malloc_map))) {
// big enough to split
split_malloc_map(current_map, size);
}
malloc_used++;
current_map->type = MALLOC_TYPE_USED;
result = ((void *) current_map) + sizeof(malloc_map);
break;
malloc_find_next:
current_map = current_map->next;
} while (current_map != first_malloc_entry);
task_lock_free();
return result;
return 0;
}
void free(void *mem) {
if (mem == NULL) {
return;
}
malloc_used--;
malloc_map *map = (mem - sizeof(malloc_map));
map->type = MALLOC_TYPE_FREE;
/** This function unlocks what was previously locked by the liballoc_lock
* function. If it disabled interrupts, it enables interrupts. If it
* had acquiried a spinlock, it releases the spinlock. etc.
*
* \return 0 if the lock was successfully released.
*/
int liballoc_unlock() {
task_lock_free();
return 0;
}
/** This is the hook into the local system which allocates pages. It
* accepts an integer parameter which is the number of pages
* required. The page size was set up in the liballoc_init function.
*
* \return NULL if the pages were not allocated.
* \return A pointer to the allocated memory.
*/
void *liballoc_alloc(size_t size) {
return pmm_get_pages(size);
}
/** This frees previously allocated memory. The void* parameter passed
* to the function is the exact same value returned from a previous
* liballoc_alloc call.
*
* The integer value is the number of pages to free.
*
* \return 0 if the memory was successfully freed.
*/
int liballoc_free(void *addr, size_t size) {
pmm_free_pages(addr, size);
return 0;
}
/** Durand's Amazing Super Duper Memory functions. */
#define VERSION "1.1"
#define ALIGNMENT 16ul//4ul ///< This is the byte alignment that memory must be allocated on. IMPORTANT for GTK and other stuff.
#define ALIGN_TYPE char ///unsigned char[16] /// unsigned short
#define ALIGN_INFO sizeof(ALIGN_TYPE)*16 ///< Alignment information is stored right before the pointer. This is the number of bytes of information stored there.
#define USE_CASE1
#define USE_CASE2
#define USE_CASE3
#define USE_CASE4
#define USE_CASE5
/** This macro will conveniently align our pointer upwards */
#define ALIGN(ptr) \
if ( ALIGNMENT > 1 ) \
{ \
uintptr_t diff; \
ptr = (void*)((uintptr_t)ptr + ALIGN_INFO); \
diff = (uintptr_t)ptr & (ALIGNMENT-1); \
if ( diff != 0 ) \
{ \
diff = ALIGNMENT - diff; \
ptr = (void*)((uintptr_t)ptr + diff); \
} \
*((ALIGN_TYPE*)((uintptr_t)ptr - ALIGN_INFO)) = \
diff + ALIGN_INFO; \
}
#define UNALIGN(ptr) \
if ( ALIGNMENT > 1 ) \
{ \
uintptr_t diff = *((ALIGN_TYPE*)((uintptr_t)ptr - ALIGN_INFO)); \
if ( diff < (ALIGNMENT + ALIGN_INFO) ) \
{ \
ptr = (void*)((uintptr_t)ptr - diff); \
} \
}
#define LIBALLOC_MAGIC 0xc001c0de
#define LIBALLOC_DEAD 0xdeaddead
#if defined DEBUG || defined INFO
// todo support debug info
//#include <stdio.h>
//#include <stdlib.h>
//#define FLUSH() fflush( stdout )
#define FLUSH() ;
#endif
/** A structure found at the top of all system allocated
* memory blocks. It details the usage of the memory block.
*/
struct liballoc_major {
struct liballoc_major *prev; ///< Linked list information.
struct liballoc_major *next; ///< Linked list information.
unsigned int pages; ///< The number of pages in the block.
unsigned int size; ///< The number of pages in the block.
unsigned int usage; ///< The number of bytes used in the block.
struct liballoc_minor *first; ///< A pointer to the first allocated memory in the block.
};
void print_malloc_info() {
printf("Malloc avail entries: %d\n"
"Malloc used entries: %d\n", malloc_entries, malloc_used);
/** This is a structure found at the beginning of all
* sections in a major block which were allocated by a
* malloc, calloc, realloc call.
*/
struct liballoc_minor {
struct liballoc_minor *prev; ///< Linked list information.
struct liballoc_minor *next; ///< Linked list information.
struct liballoc_major *block; ///< The owning block. A pointer to the major structure.
unsigned int magic; ///< A magic number to idenfity correctness.
unsigned int size; ///< The size of the memory allocated. Could be 1 byte or more.
unsigned int req_size; ///< The size of memory requested.
};
static struct liballoc_major *l_memRoot = NULL; ///< The root memory block acquired from the system.
static struct liballoc_major *l_bestBet = NULL; ///< The major with the most free memory.
static unsigned int l_pageSize = PAGE_SIZE; ///< The size of an individual page. Set up in liballoc_init.
static unsigned int l_pageCount = 16; ///< The number of pages to request per chunk. Set up in liballoc_init.
static uint32_t l_allocated = 0; ///< Running total of allocated memory.
static uint32_t l_inuse = 0; ///< Running total of used memory.
static uint32_t l_warningCount = 0; ///< Number of warnings encountered
static uint32_t l_errorCount = 0; ///< Number of actual errors
static uint32_t l_possibleOverruns = 0; ///< Number of possible overruns
// *********** HELPER FUNCTIONS *******************************
static void *liballoc_memset(void *s, int c, size_t n) {
unsigned int i;
for (i = 0; i < n; i++)
((char *) s)[i] = c;
return s;
}
static void *liballoc_memcpy(void *s1, const void *s2, size_t n) {
char *cdest;
char *csrc;
unsigned int *ldest = (unsigned int *) s1;
unsigned int *lsrc = (unsigned int *) s2;
while (n >= sizeof(unsigned int)) {
*ldest++ = *lsrc++;
n -= sizeof(unsigned int);
}
cdest = (char *) ldest;
csrc = (char *) lsrc;
while (n > 0) {
*cdest++ = *csrc++;
n -= 1;
}
return s1;
}
#if defined DEBUG || defined INFO
static void liballoc_dump()
{
#ifdef DEBUG
struct liballoc_major *maj = l_memRoot;
struct liballoc_minor *min = NULL;
#endif
printf( "liballoc: ------ Memory data ---------------\n");
printf( "liballoc: System memory allocated: %i bytes\n", l_allocated );
printf( "liballoc: Memory in used (malloc'ed): %i bytes\n", l_inuse );
printf( "liballoc: Warning count: %i\n", l_warningCount );
printf( "liballoc: Error count: %i\n", l_errorCount );
printf( "liballoc: Possible overruns: %i\n", l_possibleOverruns );
#ifdef DEBUG
while ( maj != NULL )
{
printf( "liballoc: %x: total = %i, used = %i\n",
maj,
maj->size,
maj->usage );
min = maj->first;
while ( min != NULL )
{
printf( "liballoc: %x: %i bytes\n",
min,
min->size );
min = min->next;
}
maj = maj->next;
}
#endif
FLUSH();
}
#endif
// ***************************************************************
static struct liballoc_major *allocate_new_page(unsigned int size) {
unsigned int st;
struct liballoc_major *maj;
// This is how much space is required.
st = size + sizeof(struct liballoc_major);
st += sizeof(struct liballoc_minor);
// Perfect amount of space?
if ((st % l_pageSize) == 0)
st = st / (l_pageSize);
else
st = st / (l_pageSize) + 1;
// No, add the buffer.
// Make sure it's >= the minimum size.
if (st < l_pageCount) st = l_pageCount;
maj = (struct liballoc_major *) liballoc_alloc(st);
if (maj == NULL) {
l_warningCount += 1;
#if defined DEBUG || defined INFO
printf( "liballoc: WARNING: liballoc_alloc( %i ) return NULL\n", st );
FLUSH();
#endif
return NULL; // uh oh, we ran out of memory.
}
maj->prev = NULL;
maj->next = NULL;
maj->pages = st;
maj->size = st * l_pageSize;
maj->usage = sizeof(struct liballoc_major);
maj->first = NULL;
l_allocated += maj->size;
#ifdef DEBUG
printf( "liballoc: Resource allocated %x of %i pages (%i bytes) for %i size.\n", maj, st, maj->size, size );
printf( "liballoc: Total memory usage = %i KB\n", (int)((l_allocated / (1024))) );
FLUSH();
#endif
return maj;
}
void *malloc(size_t req_size) {
int startedBet = 0;
unsigned long long bestSize = 0;
void *p = NULL;
uintptr_t diff;
struct liballoc_major *maj;
struct liballoc_minor *min;
struct liballoc_minor *new_min;
unsigned long size = req_size;
// For alignment, we adjust size so there's enough space to align.
if (ALIGNMENT > 1) {
size += ALIGNMENT + ALIGN_INFO;
}
// So, ideally, we really want an alignment of 0 or 1 in order
// to save space.
liballoc_lock();
if (size == 0) {
l_warningCount += 1;
#if defined DEBUG || defined INFO
printf( "liballoc: WARNING: alloc( 0 ) called from %x\n",
__builtin_return_address(0) );
FLUSH();
#endif
liballoc_unlock();
return malloc(1);
}
if (l_memRoot == NULL) {
#if defined DEBUG || defined INFO
#ifdef DEBUG
printf( "liballoc: initialization of liballoc " VERSION "\n" );
#endif
// atexit( liballoc_dump );
FLUSH();
#endif
// This is the first time we are being used.
l_memRoot = allocate_new_page(size);
if (l_memRoot == NULL) {
liballoc_unlock();
#ifdef DEBUG
printf( "liballoc: initial l_memRoot initialization failed\n", p);
FLUSH();
#endif
return NULL;
}
#ifdef DEBUG
printf( "liballoc: set up first memory major %x\n", l_memRoot );
FLUSH();
#endif
}
#ifdef DEBUG
printf( "liballoc: %x malloc( %i ): ",
__builtin_return_address(0),
size );
FLUSH();
#endif
// Now we need to bounce through every major and find enough space....
maj = l_memRoot;
startedBet = 0;
// Start at the best bet....
if (l_bestBet != NULL) {
bestSize = l_bestBet->size - l_bestBet->usage;
if (bestSize > (size + sizeof(struct liballoc_minor))) {
maj = l_bestBet;
startedBet = 1;
}
}
while (maj != NULL) {
diff = maj->size - maj->usage;
// free memory in the block
if (bestSize < diff) {
// Hmm.. this one has more memory then our bestBet. Remember!
l_bestBet = maj;
bestSize = diff;
}
#ifdef USE_CASE1
// CASE 1: There is not enough space in this major block.
if (diff < (size + sizeof(struct liballoc_minor))) {
#ifdef DEBUG
printf( "CASE 1: Insufficient space in block %x\n", maj);
FLUSH();
#endif
// Another major block next to this one?
if (maj->next != NULL) {
maj = maj->next; // Hop to that one.
continue;
}
if (startedBet == 1) // If we started at the best bet,
{ // let's start all over again.
maj = l_memRoot;
startedBet = 0;
continue;
}
// Create a new major block next to this one and...
maj->next = allocate_new_page(size); // next one will be okay.
if (maj->next == NULL) break; // no more memory.
maj->next->prev = maj;
maj = maj->next;
// .. fall through to CASE 2 ..
}
#endif
#ifdef USE_CASE2
// CASE 2: It's a brand new block.
if (maj->first == NULL) {
maj->first = (struct liballoc_minor *) ((uintptr_t) maj + sizeof(struct liballoc_major));
maj->first->magic = LIBALLOC_MAGIC;
maj->first->prev = NULL;
maj->first->next = NULL;
maj->first->block = maj;
maj->first->size = size;
maj->first->req_size = req_size;
maj->usage += size + sizeof(struct liballoc_minor);
l_inuse += size;
p = (void *) ((uintptr_t) (maj->first) + sizeof(struct liballoc_minor));
ALIGN(p);
#ifdef DEBUG
printf( "CASE 2: returning %x\n", p);
FLUSH();
#endif
liballoc_unlock(); // release the lock
return p;
}
#endif
#ifdef USE_CASE3
// CASE 3: Block in use and enough space at the start of the block.
diff = (uintptr_t) (maj->first);
diff -= (uintptr_t) maj;
diff -= sizeof(struct liballoc_major);
if (diff >= (size + sizeof(struct liballoc_minor))) {
// Yes, space in front. Squeeze in.
maj->first->prev = (struct liballoc_minor *) ((uintptr_t) maj + sizeof(struct liballoc_major));
maj->first->prev->next = maj->first;
maj->first = maj->first->prev;
maj->first->magic = LIBALLOC_MAGIC;
maj->first->prev = NULL;
maj->first->block = maj;
maj->first->size = size;
maj->first->req_size = req_size;
maj->usage += size + sizeof(struct liballoc_minor);
l_inuse += size;
p = (void *) ((uintptr_t) (maj->first) + sizeof(struct liballoc_minor));
ALIGN(p);
#ifdef DEBUG
printf( "CASE 3: returning %x\n", p);
FLUSH();
#endif
liballoc_unlock(); // release the lock
return p;
}
#endif
#ifdef USE_CASE4
// CASE 4: There is enough space in this block. But is it contiguous?
min = maj->first;
// Looping within the block now...
while (min != NULL) {
// CASE 4.1: End of minors in a block. Space from last and end?
if (min->next == NULL) {
// the rest of this block is free... is it big enough?
diff = (uintptr_t) (maj) + maj->size;
diff -= (uintptr_t) min;
diff -= sizeof(struct liballoc_minor);
diff -= min->size;
// minus already existing usage..
if (diff >= (size + sizeof(struct liballoc_minor))) {
// yay....
min->next = (struct liballoc_minor *) ((uintptr_t) min + sizeof(struct liballoc_minor) + min->size);
min->next->prev = min;
min = min->next;
min->next = NULL;
min->magic = LIBALLOC_MAGIC;
min->block = maj;
min->size = size;
min->req_size = req_size;
maj->usage += size + sizeof(struct liballoc_minor);
l_inuse += size;
p = (void *) ((uintptr_t) min + sizeof(struct liballoc_minor));
ALIGN(p);
#ifdef DEBUG
printf( "CASE 4.1: returning %x\n", p);
FLUSH();
#endif
liballoc_unlock(); // release the lock
return p;
}
}
// CASE 4.2: Is there space between two minors?
if (min->next != NULL) {
// is the difference between here and next big enough?
diff = (uintptr_t) (min->next);
diff -= (uintptr_t) min;
diff -= sizeof(struct liballoc_minor);
diff -= min->size;
// minus our existing usage.
if (diff >= (size + sizeof(struct liballoc_minor))) {
// yay......
new_min = (struct liballoc_minor *) ((uintptr_t) min + sizeof(struct liballoc_minor) + min->size);
new_min->magic = LIBALLOC_MAGIC;
new_min->next = min->next;
new_min->prev = min;
new_min->size = size;
new_min->req_size = req_size;
new_min->block = maj;
min->next->prev = new_min;
min->next = new_min;
maj->usage += size + sizeof(struct liballoc_minor);
l_inuse += size;
p = (void *) ((uintptr_t) new_min + sizeof(struct liballoc_minor));
ALIGN(p);
#ifdef DEBUG
printf( "CASE 4.2: returning %x\n", p);
FLUSH();
#endif
liballoc_unlock(); // release the lock
return p;
}
} // min->next != NULL
min = min->next;
} // while min != NULL ...
#endif
#ifdef USE_CASE5
// CASE 5: Block full! Ensure next block and loop.
if (maj->next == NULL) {
#ifdef DEBUG
printf( "CASE 5: block full\n");
FLUSH();
#endif
if (startedBet == 1) {
maj = l_memRoot;
startedBet = 0;
continue;
}
// we've run out. we need more...
maj->next = allocate_new_page(size); // next one guaranteed to be okay
if (maj->next == NULL) break; // uh oh, no more memory.....
maj->next->prev = maj;
}
#endif
maj = maj->next;
} // while (maj != NULL)
liballoc_unlock(); // release the lock
#ifdef DEBUG
printf( "All cases exhausted. No memory available.\n");
FLUSH();
#endif
#if defined DEBUG || defined INFO
printf( "liballoc: WARNING: malloc( %i ) returning NULL.\n", size);
liballoc_dump();
FLUSH();
#endif
return NULL;
}
void free(void *ptr) {
struct liballoc_minor *min;
struct liballoc_major *maj;
if (ptr == NULL) {
l_warningCount += 1;
#if defined DEBUG || defined INFO
printf( "liballoc: WARNING: free( NULL ) called from %x\n",
__builtin_return_address(0) );
FLUSH();
#endif
return;
}
UNALIGN(ptr);
liballoc_lock(); // lockit
min = (struct liballoc_minor *) ((uintptr_t) ptr - sizeof(struct liballoc_minor));
if (min->magic != LIBALLOC_MAGIC) {
l_errorCount += 1;
// Check for overrun errors. For all bytes of LIBALLOC_MAGIC
if (
((min->magic & 0xFFFFFF) == (LIBALLOC_MAGIC & 0xFFFFFF)) ||
((min->magic & 0xFFFF) == (LIBALLOC_MAGIC & 0xFFFF)) ||
((min->magic & 0xFF) == (LIBALLOC_MAGIC & 0xFF))
) {
l_possibleOverruns += 1;
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: Possible 1-3 byte overrun for magic %x != %x\n",
min->magic,
LIBALLOC_MAGIC );
FLUSH();
#endif
}
if (min->magic == LIBALLOC_DEAD) {
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: multiple free() attempt on %x from %x.\n",
ptr,
__builtin_return_address(0) );
FLUSH();
#endif
} else {
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: Bad free( %x ) called from %x\n",
ptr,
__builtin_return_address(0) );
FLUSH();
#endif
}
// being lied to...
liballoc_unlock(); // release the lock
return;
}
#ifdef DEBUG
printf( "liballoc: %x free( %x ): ",
__builtin_return_address( 0 ),
ptr );
FLUSH();
#endif
maj = min->block;
l_inuse -= min->size;
maj->usage -= (min->size + sizeof(struct liballoc_minor));
min->magic = LIBALLOC_DEAD; // No mojo.
if (min->next != NULL) min->next->prev = min->prev;
if (min->prev != NULL) min->prev->next = min->next;
if (min->prev == NULL) maj->first = min->next;
// Might empty the block. This was the first
// minor.
// We need to clean up after the majors now....
if (maj->first == NULL) // Block completely unused.
{
if (l_memRoot == maj) l_memRoot = maj->next;
if (l_bestBet == maj) l_bestBet = NULL;
if (maj->prev != NULL) maj->prev->next = maj->next;
if (maj->next != NULL) maj->next->prev = maj->prev;
l_allocated -= maj->size;
liballoc_free(maj, maj->pages);
} else {
if (l_bestBet != NULL) {
int bestSize = l_bestBet->size - l_bestBet->usage;
int majSize = maj->size - maj->usage;
if (majSize > bestSize) l_bestBet = maj;
}
}
#ifdef DEBUG
printf( "OK\n");
FLUSH();
#endif
liballoc_unlock(); // release the lock
}
void *calloc(size_t nobj, size_t size) {
int real_size;
void *p;
real_size = nobj * size;
p = malloc(real_size);
liballoc_memset(p, 0, real_size);
return p;
}
void *realloc(void *p, size_t size) {
void *ptr;
struct liballoc_minor *min;
unsigned int real_size;
// Honour the case of size == 0 => free old and return NULL
if (size == 0) {
free(p);
return NULL;
}
// In the case of a NULL pointer, return a simple malloc.
if (p == NULL) return malloc(size);
// Unalign the pointer if required.
ptr = p;
UNALIGN(ptr);
liballoc_lock(); // lockit
min = (struct liballoc_minor *) ((uintptr_t) ptr - sizeof(struct liballoc_minor));
// Ensure it is a valid structure.
if (min->magic != LIBALLOC_MAGIC) {
l_errorCount += 1;
// Check for overrun errors. For all bytes of LIBALLOC_MAGIC
if (
((min->magic & 0xFFFFFF) == (LIBALLOC_MAGIC & 0xFFFFFF)) ||
((min->magic & 0xFFFF) == (LIBALLOC_MAGIC & 0xFFFF)) ||
((min->magic & 0xFF) == (LIBALLOC_MAGIC & 0xFF))
) {
l_possibleOverruns += 1;
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: Possible 1-3 byte overrun for magic %x != %x\n",
min->magic,
LIBALLOC_MAGIC );
FLUSH();
#endif
}
if (min->magic == LIBALLOC_DEAD) {
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: multiple free() attempt on %x from %x.\n",
ptr,
__builtin_return_address(0) );
FLUSH();
#endif
} else {
#if defined DEBUG || defined INFO
printf( "liballoc: ERROR: Bad free( %x ) called from %x\n",
ptr,
__builtin_return_address(0) );
FLUSH();
#endif
}
// being lied to...
liballoc_unlock(); // release the lock
return NULL;
}
// Definitely a memory block.
real_size = min->req_size;
if (real_size >= size) {
min->req_size = size;
liballoc_unlock();
return p;
}
liballoc_unlock();
// If we got here then we're reallocating to a block bigger than us.
ptr = malloc(size); // We need to allocate new memory
liballoc_memcpy(ptr, p, real_size);
free(p);
return ptr;
}
void print_malloc_info() {
#if defined DEBUG || defined INFO
liballoc_dump();
#else
printf("%d bytes allocated\n%d bytes in use\n%d warnings, %d errors, %d possible overruns\n",
l_allocated, l_inuse, l_warningCount, l_errorCount, l_possibleOverruns);
#endif
}

13
kernel/mem/malloc.h
View File

@@ -4,14 +4,17 @@
#ifndef NEW_KERNEL_MALLOC_H
#define NEW_KERNEL_MALLOC_H
// retrieved from https://github.com/blanham/liballoc
#include <types.h>
void malloc_init();
void *malloc(size_t);
void *realloc(void *, size_t);
void *calloc(size_t, size_t);
void free(void *);
void print_malloc_info();
void *malloc(size_t size);
void free(void *mem);
#endif //NEW_KERNEL_MALLOC_H