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Merge branch 'srs.master'

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This commit is contained in:
winlin 2014-11-10 11:48:31 +08:00
commit 6a86537729
1 changed files with 16 additions and 0 deletions
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16
trunk/research/st/stk.c
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@ -55,12 +55,28 @@ int _st_randomize_stacks = 0;
static char *_st_new_stk_segment(int size);
/**
The below comments is by winlin:
The stack memory struct:
| REDZONE | stack | extra | REDZONE |
+---------+------------------------+---------+---------+
| 4k | | 4k/0 | 4k |
+---------+------------------------+---------+---------+
vaddr bottom top
When _st_randomize_stacks is on, by st_randomize_stacks(),
the bottom and top will random movided in the extra:
long offset = (random() % extra) & ~0xf;
ts->stk_bottom += offset;
ts->stk_top += offset;
Both REDZONE are protected by mprotect when DEBUG is on.
*/
_st_stack_t *_st_stack_new(int stack_size)
{
_st_clist_t *qp;
_st_stack_t *ts;
int extra;
// TODO: WINLIN: remove the stack reuse.
for (qp = _st_free_stacks.next; qp != &_st_free_stacks; qp = qp->next) {
ts = _ST_THREAD_STACK_PTR(qp);
if (ts->stk_size >= stack_size) {