genode/repos/base-hw/src/core/kernel/lock.cc
Stefan Kalkowski 8e13b376b0 hw: improve cross-cpu synchronization
This commit addresses several multiprocessing issues in base-hw:

* it reworks cross-cpu maintainance work for TLB invalidation by
  introducing a generic Inter_processor_work and removes the so
  called Cpu_domain_update
* thereby it solves the cross-cpu thread destruction, when the
  corresponding thread is active on another cpu (fix #3043)
* it adds the missing TLB shootdown for x86 (fix #3042)
* on ARM it removes the TLB shootdown via IPIs, because this
  is not needed on the multiprocessing ARM platforms we support
* it enables the per-cpu initialization of the kernel's cpu
  objects, which means those object initialization is executed
  by the proper cpu
* it rollbacks prior decision to make multiprocessing an aspect,
  but puts back certain 'smp' mechanisms (like cross-cpu lock)
  into the generic code base for simplicity reasons
2019-01-07 12:25:44 +01:00

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/*
* \brief Kernel lock for multi-processor systems
* \author Stefan Kalkowski
* \date 2018-11-20
*/
/*
* Copyright (C) 2019 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#include <kernel/cpu.h>
#include <kernel/lock.h>
#include <kernel/kernel.h>
Kernel::Lock & Kernel::data_lock()
{
static Kernel::Lock lock;
return lock;
}
void Kernel::Lock::lock()
{
/* check for the lock holder being the same cpu */
if (_current_cpu == Cpu::executing_id()) {
/* at least print an error message */
Genode::raw("Cpu ", _current_cpu,
" error: re-entered lock. Kernel exception?!");
for (;;) ;
}
_lock.lock();
_current_cpu = Cpu::executing_id();
}
void Kernel::Lock::unlock()
{
_current_cpu = INVALID;
_lock.unlock();
}