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RRG-Proxmark3/armsrc/umm_malloc.c
Philippe Teuwen 4c5e981958 umm: work on DBGLOG
2020-09-01 00:15:35 +02:00

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/* ----------------------------------------------------------------------------
* umm_malloc.c - a memory allocator for embedded systems (microcontrollers)
*
* From https://github.com/rhempel/umm_malloc
* See LICENSE for copyright notice
* See README.md for acknowledgements and description of internals
* ----------------------------------------------------------------------------
*
* R.Hempel 2007-09-22 - Original
* R.Hempel 2008-12-11 - Added MIT License biolerplate
* - realloc() now looks to see if previous block is free
* - made common operations functions
* R.Hempel 2009-03-02 - Added macros to disable tasking
* - Added function to dump heap and check for valid free
* pointer
* R.Hempel 2009-03-09 - Changed name to umm_malloc to avoid conflicts with
* the mm_malloc() library functions
* - Added some test code to assimilate a free block
* with the very block if possible. Complicated and
* not worth the grief.
* D.Frank 2014-04-02 - Fixed heap configuration when UMM_TEST_MAIN is NOT set,
* added user-dependent configuration file umm_malloc_cfg.h
* R.Hempel 2016-12-04 - Add support for Unity test framework
* - Reorganize source files to avoid redundant content
* - Move integrity and poison checking to separate file
* R.Hempel 2017-12-29 - Fix bug in realloc when requesting a new block that
* results in OOM error - see Issue 11
* R.Hempel 2019-09-07 - Separate the malloc() and free() functionality into
* wrappers that use critical section protection macros
* and static core functions that assume they are
* running in a protected con text. Thanks @devyte
* R.Hempel 2020-01-07 - Add support for Fragmentation metric - See Issue 14
* R.Hempel 2020-01-12 - Use explicitly sized values from stdint.h - See Issue 15
* R.Hempel 2020-01-20 - Move metric functions back to umm_info - See Issue 29
* R.Hempel 2020-02-01 - Macro functions are uppercased - See Issue 34
* R.Hempel 2020-06-20 - Support alternate body size - See Issue 42
* ----------------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include "umm_malloc_cfg.h" /* user-dependent */
#include "umm_malloc.h"
/* Use the default DBGLOG_LEVEL and DBGLOG_FUNCTION */
#define DBGLOG_LEVEL 0
#include "dbprint.h"
extern uint8_t _stack_start, __bss_end__;
/* ------------------------------------------------------------------------- */
UMM_H_ATTPACKPRE typedef struct umm_ptr_t {
uint16_t next;
uint16_t prev;
} UMM_H_ATTPACKSUF umm_ptr;
UMM_H_ATTPACKPRE typedef struct umm_block_t {
union {
umm_ptr used;
} header;
union {
umm_ptr free;
uint8_t data[UMM_BLOCK_BODY_SIZE - sizeof(struct umm_ptr_t)];
} body;
} UMM_H_ATTPACKSUF umm_block;
#define UMM_FREELIST_MASK ((uint16_t)(0x8000))
#define UMM_BLOCKNO_MASK ((uint16_t)(0x7FFF))
/* ------------------------------------------------------------------------- */
umm_block *umm_heap = NULL;
uint16_t umm_numblocks = 0;
#define UMM_NUMBLOCKS (umm_numblocks)
#define UMM_BLOCK_LAST (UMM_NUMBLOCKS - 1)
/* -------------------------------------------------------------------------
* These macros evaluate to the address of the block and data respectively
*/
#define UMM_BLOCK(b) (umm_heap[b])
#define UMM_DATA(b) (UMM_BLOCK(b).body.data)
/* -------------------------------------------------------------------------
* These macros evaluate to the index of the block - NOT the address!!!
*/
#define UMM_NBLOCK(b) (UMM_BLOCK(b).header.used.next)
#define UMM_PBLOCK(b) (UMM_BLOCK(b).header.used.prev)
#define UMM_NFREE(b) (UMM_BLOCK(b).body.free.next)
#define UMM_PFREE(b) (UMM_BLOCK(b).body.free.prev)
/* -------------------------------------------------------------------------
* There are additional files that may be included here - normally it's
* not a good idea to include .c files but in this case it keeps the
* main umm_malloc file clear and prevents issues with exposing internal
* data structures to other programs.
* -------------------------------------------------------------------------
*/
#include "umm_integrity.c"
#include "umm_poison.c"
#include "umm_info.c"
/* ------------------------------------------------------------------------ */
static uint16_t umm_blocks( size_t size ) {
/*
* The calculation of the block size is not too difficult, but there are
* a few little things that we need to be mindful of.
*
* When a block removed from the free list, the space used by the free
* pointers is available for data. That's what the first calculation
* of size is doing.
*/
if( size <= (sizeof(((umm_block *)0)->body)) )
return( 1 );
/*
* If it's for more than that, then we need to figure out the number of
* additional whole blocks the size of an umm_block are required.
*/
size -= ( 1 + (sizeof(((umm_block *)0)->body)) );
return( 2 + size/(sizeof(umm_block)) );
}
/* ------------------------------------------------------------------------ */
/*
* Split the block `c` into two blocks: `c` and `c + blocks`.
*
* - `new_freemask` should be `0` if `c + blocks` used, or `UMM_FREELIST_MASK`
* otherwise.
*
* Note that free pointers are NOT modified by this function.
*/
static void umm_split_block( uint16_t c,
uint16_t blocks,
uint16_t new_freemask ) {
UMM_NBLOCK(c+blocks) = (UMM_NBLOCK(c) & UMM_BLOCKNO_MASK) | new_freemask;
UMM_PBLOCK(c+blocks) = c;
UMM_PBLOCK(UMM_NBLOCK(c) & UMM_BLOCKNO_MASK) = (c+blocks);
UMM_NBLOCK(c) = (c+blocks);
}
/* ------------------------------------------------------------------------ */
static void umm_disconnect_from_free_list( uint16_t c ) {
/* Disconnect this block from the FREE list */
UMM_NFREE(UMM_PFREE(c)) = UMM_NFREE(c);
UMM_PFREE(UMM_NFREE(c)) = UMM_PFREE(c);
/* And clear the free block indicator */
UMM_NBLOCK(c) &= (~UMM_FREELIST_MASK);
}
/* ------------------------------------------------------------------------
* The umm_assimilate_up() function does not assume that UMM_NBLOCK(c)
* has the UMM_FREELIST_MASK bit set. It only assimilates up if the
* next block is free.
*/
static void umm_assimilate_up( uint16_t c ) {
if( UMM_NBLOCK(UMM_NBLOCK(c)) & UMM_FREELIST_MASK ) {
UMM_FRAGMENTATION_METRIC_REMOVE( UMM_NBLOCK(c) );
/*
* The next block is a free block, so assimilate up and remove it from
* the free list
*/
DBGLOGS_DEBUG( "Assimilate up to next block, which is FREE\n" );
/* Disconnect the next block from the FREE list */
umm_disconnect_from_free_list( UMM_NBLOCK(c) );
/* Assimilate the next block with this one */
UMM_PBLOCK(UMM_NBLOCK(UMM_NBLOCK(c)) & UMM_BLOCKNO_MASK) = c;
UMM_NBLOCK(c) = UMM_NBLOCK(UMM_NBLOCK(c)) & UMM_BLOCKNO_MASK;
}
}
/* ------------------------------------------------------------------------
* The umm_assimilate_down() function assumes that UMM_NBLOCK(c) does NOT
* have the UMM_FREELIST_MASK bit set. In other words, try to assimilate
* up before assimilating down.
*/
static uint16_t umm_assimilate_down( uint16_t c, uint16_t freemask ) {
// We are going to assimilate down to the previous block because
// it was free, so remove it from the fragmentation metric
UMM_FRAGMENTATION_METRIC_REMOVE(UMM_PBLOCK(c));
UMM_NBLOCK(UMM_PBLOCK(c)) = UMM_NBLOCK(c) | freemask;
UMM_PBLOCK(UMM_NBLOCK(c)) = UMM_PBLOCK(c);
if (freemask) {
// We are going to free the entire assimilated block
// so add it to the fragmentation metric. A good
// compiler will optimize away the empty if statement
// when UMM_INFO is not defined, so don't worry about
// guarding it.
UMM_FRAGMENTATION_METRIC_ADD(UMM_PBLOCK(c));
}
return( UMM_PBLOCK(c) );
}
/* ------------------------------------------------------------------------- */
void umm_init( void ) {
void *UMM_MALLOC_CFG_HEAP_ADDR = &__bss_end__;
uint32_t UMM_MALLOC_CFG_HEAP_SIZE = (uint32_t)&_stack_start - (uint32_t)&__bss_end__;
/* init heap pointer and size, and memset it to 0 */
umm_heap = (umm_block *)UMM_MALLOC_CFG_HEAP_ADDR;
umm_numblocks = (UMM_MALLOC_CFG_HEAP_SIZE / sizeof(umm_block));
memset(umm_heap, 0x00, UMM_MALLOC_CFG_HEAP_SIZE);
/* setup initial blank heap structure */
UMM_FRAGMENTATION_METRIC_INIT();
/* Set up umm_block[0], which just points to umm_block[1] */
UMM_NBLOCK(0) = 1;
UMM_NFREE(0) = 1;
UMM_PFREE(0) = 1;
/*
* Now, we need to set the whole heap space as a huge free block. We should
* not touch umm_block[0], since it's special: umm_block[0] is the head of
* the free block list. It's a part of the heap invariant.
*
* See the detailed explanation at the beginning of the file.
*
* umm_block[1] has pointers:
*
* - next `umm_block`: the last one umm_block[n]
* - prev `umm_block`: umm_block[0]
*
* Plus, it's a free `umm_block`, so we need to apply `UMM_FREELIST_MASK`
*
* And it's the last free block, so the next free block is 0 which marks
* the end of the list. The previous block and free block pointer are 0
* too, there is no need to initialize these values due to the init code
* that memsets the entire umm_ space to 0.
*/
UMM_NBLOCK(1) = UMM_BLOCK_LAST | UMM_FREELIST_MASK;
/*
* Last umm_block[n] has the next block index at 0, meaning it's
* the end of the list, and the previous block is umm_block[1].
*
* The last block is a special block and can never be part of the
* free list, so its pointers are left at 0 too.
*/
UMM_PBLOCK(UMM_BLOCK_LAST) = 1;
//DBGLOG_FORCE(true, "nblock(0) %04x pblock(0) %04x nfree(0) %04x pfree(0) %04x\n", UMM_NBLOCK(0) & UMM_BLOCKNO_MASK, UMM_PBLOCK(0), UMM_NFREE(0), UMM_PFREE(0));
//DBGLOG_FORCE(true, "nblock(1) %04x pblock(1) %04x nfree(1) %04x pfree(1) %04x\n", UMM_NBLOCK(1) & UMM_BLOCKNO_MASK, UMM_PBLOCK(1), UMM_NFREE(1), UMM_PFREE(1));
}
/* ------------------------------------------------------------------------
* Must be called only from within critical sections guarded by
* UMM_CRITICAL_ENTRY() and UMM_CRITICAL_EXIT().
*/
static void umm_free_core( void *ptr ) {
uint16_t c;
/*
* FIXME: At some point it might be a good idea to add a check to make sure
* that the pointer we're being asked to free up is actually within
* the umm_heap!
*
* NOTE: See the new umm_info() function that you can use to see if a ptr is
* on the free list!
*/
/* Figure out which block we're in. Note the use of truncated division... */
c = (((unsigned char *)ptr)-(unsigned char *)(&(umm_heap[0])))/sizeof(umm_block);
DBGLOG_DEBUG( "Freeing block %6i\n", c );
/* Now let's assimilate this block with the next one if possible. */
umm_assimilate_up( c );
/* Then assimilate with the previous block if possible */
if( UMM_NBLOCK(UMM_PBLOCK(c)) & UMM_FREELIST_MASK ) {
DBGLOGS_DEBUG( "Assimilate down to previous block, which is FREE\n" );
c = umm_assimilate_down(c, UMM_FREELIST_MASK);
} else {
/*
* The previous block is not a free block, so add this one to the head
* of the free list
*/
UMM_FRAGMENTATION_METRIC_ADD(c);
DBGLOGS_DEBUG( "Just add to head of free list\n" );
UMM_PFREE(UMM_NFREE(0)) = c;
UMM_NFREE(c) = UMM_NFREE(0);
UMM_PFREE(c) = 0;
UMM_NFREE(0) = c;
UMM_NBLOCK(c) |= UMM_FREELIST_MASK;
}
}
/* ------------------------------------------------------------------------ */
void umm_free( void *ptr ) {
if (umm_heap == NULL) {
umm_init();
}
/* If we're being asked to free a NULL pointer, well that's just silly! */
if( (void *)0 == ptr ) {
DBGLOGS_DEBUG( "free a null pointer -> do nothing\n" );
return;
}
/* Free the memory withing a protected critical section */
UMM_CRITICAL_ENTRY();
umm_free_core( ptr );
UMM_CRITICAL_EXIT();
}
/* ------------------------------------------------------------------------
* Must be called only from within critical sections guarded by
* UMM_CRITICAL_ENTRY() and UMM_CRITICAL_EXIT().
*/
static void *umm_malloc_core( size_t size ) {
uint16_t blocks;
uint16_t blockSize = 0;
uint16_t bestSize;
uint16_t bestBlock;
uint16_t cf;
blocks = umm_blocks( size );
/*
* Now we can scan through the free list until we find a space that's big
* enough to hold the number of blocks we need.
*
* This part may be customized to be a best-fit, worst-fit, or first-fit
* algorithm
*/
cf = UMM_NFREE(0);
bestBlock = UMM_NFREE(0);
bestSize = 0x7FFF;
while( cf ) {
blockSize = (UMM_NBLOCK(cf) & UMM_BLOCKNO_MASK) - cf;
DBGLOG_TRACE( "Looking at block %6i size %6i\n", cf, blockSize );
#if defined UMM_BEST_FIT
if( (blockSize >= blocks) && (blockSize < bestSize) ) {
bestBlock = cf;
bestSize = blockSize;
}
#elif defined UMM_FIRST_FIT
/* This is the first block that fits! */
if( (blockSize >= blocks) )
break;
#else
# error "No UMM_*_FIT is defined - check umm_malloc_cfg.h"
#endif
cf = UMM_NFREE(cf);
}
if( 0x7FFF != bestSize ) {
cf = bestBlock;
blockSize = bestSize;
}
if( UMM_NBLOCK(cf) & UMM_BLOCKNO_MASK && blockSize >= blocks ) {
UMM_FRAGMENTATION_METRIC_REMOVE(cf);
/*
* This is an existing block in the memory heap, we just need to split off
* what we need, unlink it from the free list and mark it as in use, and
* link the rest of the block back into the freelist as if it was a new
* block on the free list...
*/
if( blockSize == blocks ) {
/* It's an exact fit and we don't neet to split off a block. */
DBGLOG_DEBUG( "Allocating %6i blocks starting at %6i - exact\n", blocks, cf );
/* Disconnect this block from the FREE list */
umm_disconnect_from_free_list( cf );
} else {
/* It's not an exact fit and we need to split off a block. */
DBGLOG_DEBUG( "Allocating %6i blocks starting at %6i - existing\n", blocks, cf );
/*
* split current free block `cf` into two blocks. The first one will be
* returned to user, so it's not free, and the second one will be free.
*/
umm_split_block( cf, blocks, UMM_FREELIST_MASK /*new block is free*/ );
UMM_FRAGMENTATION_METRIC_ADD(UMM_NBLOCK(cf));
/*
* `umm_split_block()` does not update the free pointers (it affects
* only free flags), but effectively we've just moved beginning of the
* free block from `cf` to `cf + blocks`. So we have to adjust pointers
* to and from adjacent free blocks.
*/
/* previous free block */
UMM_NFREE( UMM_PFREE(cf) ) = cf + blocks;
UMM_PFREE( cf + blocks ) = UMM_PFREE(cf);
/* next free block */
UMM_PFREE( UMM_NFREE(cf) ) = cf + blocks;
UMM_NFREE( cf + blocks ) = UMM_NFREE(cf);
}
} else {
/* Out of memory */
DBGLOG_DEBUG( "Can't allocate %5i blocks\n", blocks );
return( (void *)NULL );
}
return( (void *)&UMM_DATA(cf) );
}
/* ------------------------------------------------------------------------ */
void *umm_malloc( size_t size ) {
void *ptr = NULL;
if (umm_heap == NULL) {
umm_init();
}
/*
* the very first thing we do is figure out if we're being asked to allocate
* a size of 0 - and if we are we'll simply return a null pointer. if not
* then reduce the size by 1 byte so that the subsequent calculations on
* the number of blocks to allocate are easier...
*/
if( 0 == size ) {
DBGLOGS_DEBUG( "malloc a block of 0 bytes -> do nothing\n" );
return( ptr );
}
/* Allocate the memory withing a protected critical section */
UMM_CRITICAL_ENTRY();
ptr = umm_malloc_core( size );
UMM_CRITICAL_EXIT();
return( ptr );
}
/* ------------------------------------------------------------------------ */
void *umm_realloc( void *ptr, size_t size ) {
uint16_t blocks;
uint16_t blockSize;
uint16_t prevBlockSize = 0;
uint16_t nextBlockSize = 0;
uint16_t c;
size_t curSize;
if (umm_heap == NULL) {
umm_init();
}
/*
* This code looks after the case of a NULL value for ptr. The ANSI C
* standard says that if ptr is NULL and size is non-zero, then we've
* got to work the same a malloc(). If size is also 0, then our version
* of malloc() returns a NULL pointer, which is OK as far as the ANSI C
* standard is concerned.
*/
if( ((void *)NULL == ptr) ) {
DBGLOGS_DEBUG( "realloc the NULL pointer - call malloc()\n" );
return( umm_malloc(size) );
}
/*
* Now we're sure that we have a non_NULL ptr, but we're not sure what
* we should do with it. If the size is 0, then the ANSI C standard says that
* we should operate the same as free.
*/
if( 0 == size ) {
DBGLOGS_DEBUG( "realloc to 0 size, just free the block\n" );
umm_free( ptr );
return( (void *)NULL );
}
/*
* Otherwise we need to actually do a reallocation. A naiive approach
* would be to malloc() a new block of the correct size, copy the old data
* to the new block, and then free the old block.
*
* While this will work, we end up doing a lot of possibly unnecessary
* copying. So first, let's figure out how many blocks we'll need.
*/
blocks = umm_blocks( size );
/* Figure out which block we're in. Note the use of truncated division... */
c = (((unsigned char *)ptr)-(unsigned char *)(&(umm_heap[0])))/sizeof(umm_block);
/* Figure out how big this block is ... the free bit is not set :-) */
blockSize = (UMM_NBLOCK(c) - c);
/* Figure out how many bytes are in this block */
curSize = (blockSize*sizeof(umm_block))-(sizeof(((umm_block *)0)->header));
/* Protect the critical section... */
UMM_CRITICAL_ENTRY();
/* Now figure out if the previous and/or next blocks are free as well as
* their sizes - this will help us to minimize special code later when we
* decide if it's possible to use the adjacent blocks.
*
* We set prevBlockSize and nextBlockSize to non-zero values ONLY if they
* are free!
*/
if ((UMM_NBLOCK(UMM_NBLOCK(c)) & UMM_FREELIST_MASK)) {
nextBlockSize = (UMM_NBLOCK(UMM_NBLOCK(c)) & UMM_BLOCKNO_MASK) - UMM_NBLOCK(c);
}
if ((UMM_NBLOCK(UMM_PBLOCK(c)) & UMM_FREELIST_MASK)) {
prevBlockSize = (c - UMM_PBLOCK(c));
}
DBGLOG_DEBUG( "realloc blocks %i blockSize %i nextBlockSize %i prevBlockSize %i\n", blocks, blockSize, nextBlockSize, prevBlockSize );
/*
* Ok, now that we're here we know how many blocks we want and the current
* blockSize. The prevBlockSize and nextBlockSize are set and we can figure
* out the best strategy for the new allocation as follows:
*
* 1. If the new block is the same size or smaller than the current block do
* nothing.
* 2. If the next block is free and adding it to the current block gives us
* EXACTLY enough memory, assimilate the next block. This avoids unwanted
* fragmentation of free memory.
*
* The following cases may be better handled with memory copies to reduce
* fragmentation
*
* 3. If the previous block is NOT free and the next block is free and
* adding it to the current block gives us enough memory, assimilate
* the next block. This may introduce a bit of fragmentation.
* 4. If the prev block is free and adding it to the current block gives us
* enough memory, remove the previous block from the free list, assimilate
* it, copy to the new block.
* 5. If the prev and next blocks are free and adding them to the current
* block gives us enough memory, assimilate the next block, remove the
* previous block from the free list, assimilate it, copy to the new block.
* 6. Otherwise try to allocate an entirely new block of memory. If the
* allocation works free the old block and return the new pointer. If
* the allocation fails, return NULL and leave the old block intact.
*
* TODO: Add some conditional code to optimise for less fragmentation
* by simply allocating new memory if we need to copy anyways.
*
* All that's left to do is decide if the fit was exact or not. If the fit
* was not exact, then split the memory block so that we use only the requested
* number of blocks and add what's left to the free list.
*/
// Case 1 - block is same size or smaller
if (blockSize >= blocks) {
DBGLOG_DEBUG( "realloc the same or smaller size block - %i, do nothing\n", blocks );
/* This space intentionally left blank */
// Case 2 - block + next block fits EXACTLY
} else if ((blockSize + nextBlockSize) == blocks) {
DBGLOG_DEBUG( "exact realloc using next block - %i\n", blocks );
umm_assimilate_up( c );
blockSize += nextBlockSize;
// Case 3 - prev block NOT free and block + next block fits
} else if ((0 == prevBlockSize) && (blockSize + nextBlockSize) >= blocks) {
DBGLOG_DEBUG( "realloc using next block - %i\n", blocks );
umm_assimilate_up( c );
blockSize += nextBlockSize;
// Case 4 - prev block + block fits
} else if ((prevBlockSize + blockSize) >= blocks) {
DBGLOG_DEBUG( "realloc using prev block - %i\n", blocks );
umm_disconnect_from_free_list( UMM_PBLOCK(c) );
c = umm_assimilate_down(c, 0);
memmove( (void *)&UMM_DATA(c), ptr, curSize );
ptr = (void *)&UMM_DATA(c);
blockSize += prevBlockSize;
// Case 5 - prev block + block + next block fits
} else if ((prevBlockSize + blockSize + nextBlockSize) >= blocks) {
DBGLOG_DEBUG( "realloc using prev and next block - %i\n", blocks );
umm_assimilate_up( c );
umm_disconnect_from_free_list( UMM_PBLOCK(c) );
c = umm_assimilate_down(c, 0);
memmove( (void *)&UMM_DATA(c), ptr, curSize );
ptr = (void *)&UMM_DATA(c);
blockSize += (prevBlockSize + nextBlockSize);
// Case 6 - default is we need to realloc a new block
} else {
DBGLOG_DEBUG( "realloc a completely new block %i\n", blocks );
void *oldptr = ptr;
if( (ptr = umm_malloc_core( size )) ) {
DBGLOG_DEBUG( "realloc %i to a bigger block %i, copy, and free the old\n", blockSize, blocks );
memcpy( ptr, oldptr, curSize );
umm_free_core( oldptr );
} else {
DBGLOG_DEBUG( "realloc %i to a bigger block %i failed - return NULL and leave the old block!\n", blockSize, blocks );
/* This space intentionally left blnk */
}
blockSize = blocks;
}
/* Now all we need to do is figure out if the block fit exactly or if we
* need to split and free ...
*/
if (blockSize > blocks ) {
DBGLOG_DEBUG( "split and free %i blocks from %i\n", blocks, blockSize );
umm_split_block( c, blocks, 0 );
umm_free_core( (void *)&UMM_DATA(c+blocks) );
}
/* Release the critical section... */
UMM_CRITICAL_EXIT();
return( ptr );
}
/* ------------------------------------------------------------------------ */
void *umm_calloc( size_t num, size_t item_size ) {
void *ret;
ret = umm_malloc((size_t)(item_size * num));
if (ret)
memset(ret, 0x00, (size_t)(item_size * num));
return ret;
}
/* ------------------------------------------------------------------------ */
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