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Added support for faulty pagers and their threads to become zombies

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Added support for pagers that fault to suspend and become zombies
along with all the threads that they manage. Zombie killing is to
be done at a later time, from this special zombie queue.

The implementation works same as a suspension, with the added action
that the thread is moved to a queue in kernel container.
This commit is contained in:
Bahadir Balban
2009-10-19 18:48:55 +03:00
parent 9177166817
commit cfa35e4a66
8 changed files with 110 additions and 78 deletions
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64
src/arch/arm/exception.c
View File

@@ -79,21 +79,29 @@ void fault_ipc_to_pager(u32 faulty_pc, u32 fsr, u32 far)
fault->fsr = fsr;
fault->far = far;
/* Write pte of the abort address, which is different on pabt/dabt */
/*
* Write pte of the abort address,
* which is different on pabt/dabt
*/
if (is_prefetch_abort(fsr))
fault->pte = virt_to_pte(faulty_pc);
else
fault->pte = virt_to_pte(far);
/*
* System calls save arguments (and message registers) on the kernel
* stack. They are then referenced from the caller's ktcb. Here, we
* forge a fault structure as if an ipc syscall has occured. Then
* the reference to the fault structure is set in the ktcb such that
* it lies on the mr0 offset when referred as the syscall context.
* System calls save arguments (and message registers)
* on the kernel stack. They are then referenced from
* the caller's ktcb. Here, we forge a fault structure
* as if an ipc syscall has occured. Then the reference
* to the fault structure is set in the ktcb such that
* it lies on the mr0 offset when referred as the syscall
* context.
*/
/* Assign fault such that it overlaps as the MR0 reference in ktcb. */
/*
* Assign fault such that it overlaps
* as the MR0 reference in ktcb.
*/
current->syscall_regs = (syscall_context_t *)
((unsigned long)&mr[0] -
offsetof(syscall_context_t, r3));
@@ -105,25 +113,28 @@ void fault_ipc_to_pager(u32 faulty_pc, u32 fsr, u32 far)
if (current->tid == current->pagerid) {
printk("Pager (%d) self-faulting. Exiting.\n",
current->tid);
thread_destroy_self();
thread_destroy_current();
}
/* Send ipc to the task's pager */
if ((err = ipc_sendrecv(current->pagerid,
current->pagerid, 0)) < 0) {
//printk("Thread (%d) faulted in kernel and its pager "
// "returned error (%d). Suspending.\n",
// current->tid, err);
printk("Thread (%d) faulted in kernel and its pager "
"returned error (%d). Suspend and exiting thread.\n",
current->tid, err);
BUG_ON(current->nlocks);
current->flags |= TASK_EXITING;
sched_suspend_sync();
}
}
/*
* When a task calls the kernel and the supplied user buffer is not mapped, the kernel
* generates a page fault to the task's pager so that the pager can make the decision
* on mapping the buffer. Remember that if a task maps its own user buffer to itself
* this way, the kernel can access it, since it shares that task's page table.
* When a task calls the kernel and the supplied user buffer is
* not mapped, the kernel generates a page fault to the task's
* pager so that the pager can make the decision on mapping the
* buffer. Remember that if a task maps its own user buffer to
* itself this way, the kernel can access it, since it shares
* that task's page table.
*/
int pager_pagein_request(unsigned long addr, unsigned long size,
unsigned int flags)
@@ -251,12 +262,6 @@ void data_abort_handler(u32 faulted_pc, u32 fsr, u32 far)
/* This notifies the pager */
fault_ipc_to_pager(faulted_pc, fsr, far);
if (current->flags & TASK_SUSPENDING) {
BUG_ON(current->nlocks);
sched_suspend_sync();
}
return;
error:
@@ -269,6 +274,7 @@ error:
while (1)
;
}
void prefetch_abort_handler(u32 faulted_pc, u32 fsr, u32 far, u32 lr)
{
set_abort_type(fsr, ARM_PABT);
@@ -280,11 +286,6 @@ void prefetch_abort_handler(u32 faulted_pc, u32 fsr, u32 far, u32 lr)
if (KERN_ADDR(lr))
goto error;
fault_ipc_to_pager(faulted_pc, fsr, far);
if (current->flags & TASK_SUSPENDING) {
BUG_ON(current->nlocks);
sched_suspend_sync();
}
return;
error:
@@ -306,14 +307,17 @@ void dump_undef_abort(u32 undef_addr)
}
extern int current_irq_nest_count;
/*
* This is called right where the nest count is increased in case the nesting
* is beyond the predefined max limit. It is another matter whether this
* limit is enough to guarantee the kernel stack is not overflown.
* This is called right where the nest count is increased
* in case the nesting is beyond the predefined max limit.
* It is another matter whether this limit is enough to
* guarantee the kernel stack is not overflown.
*/
void irq_overnest_error(void)
{
dprintk("Irqs nested beyond limit. Current count: ", current_irq_nest_count);
dprintk("Irqs nested beyond limit. Current count: ",
current_irq_nest_count);
printascii("Halting system...\n");
while(1)
;