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malloc: dlmalloc: add an ability for the malloc to be re-init/init multiple times

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Malloc gets initialized with a call to mem_malloc_init() with the address
the allocation starts to and its size. Currently it is not possible to
move the malloc from one memory area to another as the malloc would eventually
fail.

This patch adds in the ability to re-init the malloc with the updated
start address and the size.

One of the use cases of this feature is SPL U-Boot running from within
the static memory and calling to malloc init from within board_init_f():

	arch/arm/cpu/armv8/start.S:reset vector
	arch/arm/cpu/armv8/start.S:main()
	arch/arm/lib/crt0_64.S:board_init_f()
	board/<my_board>/common/spl.c:board_init_f()
        board/<my_board>/common/spl.c:mem_malloc_init((ulong)CONFIG_SYS_SPL_MALLOC_START,
                        CONFIG_SYS_SPL_MALLOC_SIZE);

Shortly after the DDR (main) memory is init and ready we call to malloc init
again but this time with the start address in the DDR memory and a much greater
size for moving the allocation off the static to the DDR memory:

	board/<my_board>/common/spl.c:mem_malloc_init((ulong)CONFIG_SPL_MALLOC_OFFSET,
			CONFIG_SPL_MALLOC_SIZE);

Where CONFIG_SYS_SPL_MALLOC_START and CONFIG_SPL_MALLOC_OFFSET are the start
addresses of the malloc in the static and DDR memories respectively and
CONFIG_SYS_SPL_MALLOC_SIZE=SZ_16K and CONFIG_SPL_MALLOC_SIZE=SZ_2M are
the sizes of the mallocs in these memories. Note, now we have a much greater
memory, enlarging from 16K to 2M, available for allocation.

There is an alternative approach already existing in U-Boot with the use of
an early (simplified) malloc and the proper (dlamalloc) malloc however
necessitating managing the two mallocs whereas this approach proposes using
a single dlmalloc.

Signed-off-by: Marek Bykowski <marek.bykowski@gmail.com>
This commit is contained in:
Marek Bykowski 2020-04-29 18:23:07 +02:00 committed by Tom Rini
parent c522949a29
commit 9297e366d6
2 changed files with 52 additions and 3 deletions
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14
Kconfig
View File

@ -209,6 +209,20 @@ if EXPERT
When disabling this, please check if malloc calls, maybe
should be replaced by calloc - if one expects zeroed memory.
config SYS_MALLOC_DEFAULT_TO_INIT
bool "Default malloc to init while reserving the memory for it"
default n
help
It may happen that one needs to move the dynamic allocation
from one to another memory range, eg. when moving the malloc
from the limited static to a potentially large dynamic (DDR)
memory.
If so then on top of setting the updated memory aside one
needs to bring the malloc init.
If such a scenario is sought choose yes.
config TOOLS_DEBUG
bool "Enable debug information for tools"
help

41
common/dlmalloc.c
View File

@ -280,6 +280,7 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused space (may be 0 bytes long) .
. .
. |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
`foot:' | Size of chunk, in bytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@ -574,6 +575,10 @@ static void malloc_bin_reloc(void)
static inline void malloc_bin_reloc(void) {}
#endif
#ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
static void malloc_init(void);
#endif
ulong mem_malloc_start = 0;
ulong mem_malloc_end = 0;
ulong mem_malloc_brk = 0;
@ -604,6 +609,10 @@ void mem_malloc_init(ulong start, ulong size)
mem_malloc_end = start + size;
mem_malloc_brk = start;
#ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
malloc_init();
#endif
debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start,
mem_malloc_end);
#ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
@ -708,7 +717,36 @@ static unsigned int max_n_mmaps = 0;
static unsigned long max_mmapped_mem = 0;
#endif
#ifdef CONFIG_SYS_MALLOC_DEFAULT_TO_INIT
static void malloc_init(void)
{
int i, j;
debug("bins (av_ array) are at %p\n", (void *)av_);
av_[0] = NULL; av_[1] = NULL;
for (i = 2, j = 2; i < NAV * 2 + 2; i += 2, j++) {
av_[i] = bin_at(j - 2);
av_[i + 1] = bin_at(j - 2);
/* Just print the first few bins so that
* we can see there are alright.
*/
if (i < 10)
debug("av_[%d]=%lx av_[%d]=%lx\n",
i, (ulong)av_[i],
i + 1, (ulong)av_[i + 1]);
}
/* Init the static bookkeeping as well */
sbrk_base = (char *)(-1);
max_sbrked_mem = 0;
max_total_mem = 0;
#ifdef DEBUG
memset((void *)&current_mallinfo, 0, sizeof(struct mallinfo));
#endif
}
#endif
/*
Debugging support
@ -1051,9 +1089,6 @@ static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
#endif /* HAVE_MMAP */
/*
Extend the top-most chunk by obtaining memory from system.
Main interface to sbrk (but see also malloc_trim).