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// IBM_PROLOG_BEGIN_TAG
// This is an automatically generated prolog.
//
// $Source: src/kernel/stacksegment.C $
//
// IBM CONFIDENTIAL
//
// COPYRIGHT International Business Machines Corp. 2011
//
// p1
//
// Object Code Only (OCO) source materials
// Licensed Internal Code Source Materials
// IBM HostBoot Licensed Internal Code
//
// The source code for this program is not published or other-
// wise divested of its trade secrets, irrespective of what has
// been deposited with the U.S. Copyright Office.
//
// Origin: 30
//
// IBM_PROLOG_END
#include <assert.h>
#include <util/singleton.H>
#include <kernel/stacksegment.H>
#include <kernel/segmentmgr.H>
#include <kernel/block.H>
#include <errno.h>
#include <usr/vmmconst.h>
void StackSegment::init()
{
Singleton<StackSegment>::instance()._init();
}
void* StackSegment::createStack(tid_t i_task)
{
return Singleton<StackSegment>::instance()._createStack(i_task);
}
void StackSegment::deleteStack(tid_t i_task)
{
Singleton<StackSegment>::instance()._deleteStack(i_task);
}
StackSegment::~StackSegment()
{
// Release all blocks and associated pages.
StackBlockNode* l_node = NULL;
do
{
l_node = iv_blockList.remove();
if (NULL != l_node)
{
l_node->block->releaseAllPages();
delete l_node->block;
delete l_node;
}
} while (l_node != NULL); /*using deallocated*/ // BEAM invalid error.
}
bool StackSegment::handlePageFault(task_t* i_task, uint64_t i_addr,
bool i_store)
{
uint64_t l_addr_8mb = i_addr & ~((8*MEGABYTE) - 1);
StackBlockNode* l_node = iv_blockList.find(l_addr_8mb);
return (NULL == l_node ?
false :
l_node->block->handlePageFault(i_task, i_addr, i_store));
}
uint64_t StackSegment::findPhysicalAddress(uint64_t i_vaddr) const
{
uint64_t l_addr_8mb = i_vaddr & ~((8*MEGABYTE) - 1);
StackBlockNode* l_node = iv_blockList.find(l_addr_8mb);
return (NULL == l_node ?
-EFAULT :
l_node->block->findPhysicalAddress(i_vaddr));
}
void StackSegment::_init()
{
// Assign segment to segment manager.
SegmentManager::addSegment(this, SegmentManager::STACK_SEGMENT_ID);
}
void* StackSegment::_createStack(tid_t i_task)
{
/* The segment is broken out into 8MB blocks so we need to place the
* stack somewhere within an 8MB range. The constraints are ensuring
* we have adequate protection and that the hashed page table does not
* have a large number of collisions. If we were to place all of the
* stacks at (8MB - 64k) there would be a large amount of contention on
* the same PTEG in the hashed page table.
*
* Design:
* - Provide 64k of protection minimum at the top and bottom of the
* stack.
* - Allow stack sizes up to 256k.
* - Expect typical (well performing) stacks of under 128k.
*
* Therefore, place stacks at:
* Bottom = 64k + 128k * (tid % 61).
* Top = Bottom + 256k - 8.
*
* This provides a possible range of 64k to (8MB - 64k), giving 64k of
* protection at each end. It also cycles the stacks through the 8MB
* range, and therefore the hashed page table, at 128k blocks. Finally,
* it provides for stack sizes up to 256k.
*
* Any attempt to grow the stack above 256k can be caught by killing the
* task (so we can re-write the offending code to not waste so much stack
* space).
*/
uint64_t l_addr_8mb = i_task * (8*MEGABYTE) + VMM_VADDR_STACK_SEGMENT;
// Ensure block doesn't already exist.
kassert(NULL == iv_blockList.find(l_addr_8mb));
// Calculate offset bounds of stack.
uint64_t l_offset_bottom = (64 + 128 * (i_task % 61)) * 1024;
uint64_t l_offset_top = l_offset_bottom + (256 * 1024) - 8;
uint64_t l_addr_bottom = l_addr_8mb + l_offset_bottom;
uint64_t l_addr_top = l_addr_8mb + l_offset_top;
// Create block.
Block* l_block = new Block(l_addr_bottom, 256 * 1024);
// Set pages to be allocate-from-zero.
for(uint64_t i = l_addr_bottom; i <= l_addr_top; i += PAGE_SIZE)
{
l_block->setPhysicalPage(i, 0, WRITABLE | ALLOCATE_FROM_ZERO);
}
// Insert block to list.
StackBlockNode* l_node = new StackBlockNode();
l_node->key = l_addr_8mb;
l_node->block = l_block;
iv_blockList.insert(l_node);
// Return pointer to top of stack, since stacks grow down.
return reinterpret_cast<void*>(l_addr_top);
}
void StackSegment::_deleteStack(tid_t i_task)
{
VmmManager::getLock()->lock();
uint64_t l_addr_8mb = i_task * (8*MEGABYTE) + VMM_VADDR_STACK_SEGMENT;
StackBlockNode* l_node = iv_blockList.find(l_addr_8mb);
kassert(NULL != l_node);
iv_blockList.erase(l_node);
l_node->block->releaseAllPages();
delete l_node->block;
delete l_node;
VmmManager::getLock()->unlock();
return;
}
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