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Mapping precision fixes on l4_unmap and do_munmap()

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l4_unmap now returns -1 if given range was only partially unmapped.

do_munmap() now only unmaps address ranges that have correspondence in
the unmapped vmas. Trying to unmap regions with no correspondent vmas
causes problems in corner cases, e.g. mm0 that tries to mmap its own
address space during initialisation would unmap its whole address space
and fail to execute.
This commit is contained in:
Bahadir Balban
2008-11-08 10:18:35 +02:00
parent 0e3f069713
commit 94daebd0c5
7 changed files with 82 additions and 39 deletions
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30
src/api/space.c
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@@ -40,26 +40,30 @@ found:
return 0;
}
/*
* Unmaps given range from given task. If the complete range is unmapped
* sucessfully, returns 0. If part of the range was found to be already
* unmapped, returns -1. This is may or may not be an error.
*/
int sys_unmap(syscall_context_t *regs)
{
unsigned long virt = regs->r0;
unsigned long virtual = regs->r0;
unsigned long npages = regs->r1;
unsigned int tid = regs->r2;
struct ktcb *target;
int ret, retval;
if (tid == current->tid) { /* The easiest case */
if (tid == current->tid)
target = current;
goto found;
} else /* else search the tcb from its hash list */
if ((target = find_task(tid)))
goto found;
BUG();
return -EINVAL;
found:
for (int i = 0; i < npages; i++)
remove_mapping_pgd(virt, target->pgd);
else if (!(target = find_task(tid)))
return -ESRCH;
return 0;
for (int i = 0; i < npages; i++) {
ret = remove_mapping_pgd(virtual + i * PAGE_SIZE, target->pgd);
if (ret)
retval = ret;
}
return retval;
}