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Merge pull request #2252 from benpicco/samd21-malloc

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cpu/samd21: check if the requested memory is really available in _sbrk_r
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benpicco 2015-01-06 20:31:09 +01:00
commit 9c50f206c5
2 changed files with 19 additions and 9 deletions
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4
cpu/samd21/samd21_linkerscript.ld
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@ -139,6 +139,8 @@ SECTIONS
_estack = .;
} > ram
/* heap section */
. = ALIGN(4);
_end = . ;
_sheap = . ;
_eheap = ORIGIN(ram) + LENGTH(ram);
}

24
cpu/samd21/syscalls.c
View File

@ -44,8 +44,9 @@
/**
* manage the heap
*/
extern uint32_t _end; /* address of last used memory cell */
caddr_t heap_top = (caddr_t)&_end + 4;
extern char _sheap; /* start of the heap */
extern char _eheap; /* end of the heap */
caddr_t heap_top = (caddr_t)&_sheap + 4;
#ifndef MODULE_UART0
/**
@ -115,18 +116,25 @@ void _exit(int n)
*
* The current heap implementation is very rudimentary, it is only able to allocate
* memory. But it does not
* - check if the returned address is valid (no check if the memory very exists)
* - have any means to free memory again
*
* TODO: check if the requested memory is really available
*
* @return [description]
* @return Upon successful completion, sbrk() returns the prior break value.
* Otherwise, it returns (void *)-1 and sets errno to indicate the error.
*/
caddr_t _sbrk_r(struct _reent *r, size_t incr)
caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
{
unsigned int state = disableIRQ();
caddr_t res = heap_top;
heap_top += incr;
if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
r->_errno = ENOMEM;
res = (void *) -1;
}
else {
heap_top += incr;
}
restoreIRQ(state);
return res;
}