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hw: use kernel signal API for page-fault signals 

Instead of using the Genode user-level signal API to signal page-faults to
a page-fault handler, use the kernel API directly. Thereby the accounting
of signal contexts needed for each paging subject can be done easily.

Fix #956
This commit is contained in:
Stefan Kalkowski 2015-06-22 14:44:28 +02:00 committed by Christian Helmuth
parent 57e2f3affc
commit f5d5ed9637
5 changed files with 43 additions and 122 deletions
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2
repos/base-hw/src/core/include/kernel/signal_receiver.h
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@ -270,7 +270,7 @@ class Kernel::Signal_context : public Kernel::Object
*/
static capid_t syscall_create(void * p,
Signal_receiver * const receiver,
unsigned const imprint)
addr_t const imprint)
{
return call(call_id_new_signal_context(), (Call_arg)p,
(Call_arg)receiver, (Call_arg)imprint);

95
repos/base-hw/src/core/include/pager.h
View File

@ -20,6 +20,8 @@
#include <base/signal.h>
#include <pager/capability.h>
#include <unmanaged_singleton.h>
#include <kernel/signal_receiver.h>
#include <object.h>
namespace Genode
{
@ -124,53 +126,16 @@ class Genode::Ipc_pager
void set_reply_mapping(Mapping m);
};
class Genode::Pager_object : public Object_pool<Pager_object>::Entry,
public Signal_context
class Genode::Pager_object
: public Object_pool<Pager_object>::Entry,
public Genode::Kernel_object<Kernel::Signal_context>
{
friend class Pager_entrypoint;
private:
Signal_context_capability _signal_context_cap;
Thread_capability _thread_cap;
bool _signal_valid;
char _signal_buf[sizeof(Signal)];
unsigned long const _badge;
/**
* Remember an incoming fault for handling
*
* \param s fault signal
*/
void _take_fault(Signal const & s)
{
new (_signal_buf) Signal(s);
_signal_valid = 1;
}
/**
* End handling of current fault
*/
void _end_fault()
{
_signal()->~Signal();
_signal_valid = 0;
}
/**
* End handling of current fault if there is one
*/
void _end_fault_if_pending()
{
if (_signal_valid) { _end_fault(); }
}
/***************
** Accessors **
***************/
Signal * _signal() const;
Thread_capability _thread_cap;
unsigned long const _badge;
public:
@ -181,18 +146,6 @@ class Genode::Pager_object : public Object_pool<Pager_object>::Entry,
*/
Pager_object(unsigned const badge, Affinity::Location);
/**
* The faulter has caused a fault and awaits paging
*
* \param s signal that communicated the fault
*/
void fault_occured(Signal const & s) { _take_fault(s); }
/**
* Current fault has been resolved so resume faulter
*/
void fault_resolved() { _end_fault(); }
/**
* User identification of pager object
*/
@ -211,25 +164,9 @@ class Genode::Pager_object : public Object_pool<Pager_object>::Entry,
/**
* Install information that is necessary to handle page faults
*
* \param c linkage between signal context and a signal receiver
* \param p linkage between pager object and a pager entry-point
* \param receiver signal receiver that receives the page faults
*/
void start_paging(Signal_context_capability const & c,
Pager_capability const & p)
{
_signal_context_cap = c;
Object_pool<Pager_object>::Entry::cap(p);
}
/**
* Uninstall paging information and cancel unresolved faults
*/
void stop_paging()
{
Object_pool<Pager_object>::Entry::cap(Native_capability());
_signal_context_cap = Signal_context_capability();
_end_fault_if_pending();
}
void start_paging(Kernel::Signal_receiver * receiver);
/**
* Called when a page-fault finally could not be resolved
@ -259,18 +196,16 @@ class Genode::Pager_object : public Object_pool<Pager_object>::Entry,
Thread_capability thread_cap() const;
void thread_cap(Thread_capability const & c);
unsigned signal_context_id() const;
};
class Genode::Pager_activation_base : public Thread_base,
public Signal_receiver,
public Ipc_pager
class Genode::Pager_activation_base
: public Thread_base,
public Kernel_object<Kernel::Signal_receiver>,
public Ipc_pager
{
private:
Native_capability _cap;
Lock _cap_valid;
Lock _startup_lock;
Pager_entrypoint * _ep;
public:
@ -304,8 +239,6 @@ class Genode::Pager_activation_base : public Thread_base,
** Accessors **
***************/
Native_capability cap();
void ep(Pager_entrypoint * const ep);
};

53
repos/base-hw/src/core/pager.cc
View File

@ -66,9 +66,20 @@ Thread_capability Pager_object::thread_cap() const { return _thread_cap; }
void Pager_object::thread_cap(Thread_capability const & c) { _thread_cap = c; }
Signal * Pager_object::_signal() const { return (Signal *)_signal_buf; }
void Pager_object::wake_up()
{
using Object = Kernel_object<Kernel::Signal_context>;
Kernel::ack_signal(Object::_cap.dst());
}
void Pager_object::wake_up() { fault_resolved(); }
void Pager_object::start_paging(Kernel::Signal_receiver * receiver)
{
using Object = Kernel_object<Kernel::Signal_context>;
using Entry = Object_pool<Pager_object>::Entry;
create(receiver, (unsigned long)this);
Entry::cap(Object::_cap);
}
void Pager_object::exception_handler(Signal_context_capability) { }
@ -81,18 +92,11 @@ void Pager_object::unresolved_page_fault_occurred()
}
Pager_object::Pager_object(unsigned const badge, Affinity::Location)
:
_signal_valid(0),
_badge(badge)
: Object_pool<Pager_object>::Entry(Kernel_object<Kernel::Signal_context>::_cap),
_badge(badge)
{ }
unsigned Pager_object::signal_context_id() const
{
return _signal_context_cap.dst();
}
/***************************
** Pager_activation_base **
***************************/
@ -102,18 +106,12 @@ void Pager_activation_base::ep(Pager_entrypoint * const ep) { _ep = ep; }
Pager_activation_base::Pager_activation_base(char const * const name,
size_t const stack_size)
:
Thread_base(0, name, stack_size), _cap_valid(Lock::LOCKED), _ep(0)
: Thread_base(0, name, stack_size),
Kernel_object<Kernel::Signal_receiver>(true),
_startup_lock(Lock::LOCKED), _ep(0)
{ }
Native_capability Pager_activation_base::cap()
{
if (!_cap.valid()) { _cap_valid.lock(); }
return _cap;
}
/**********************
** Pager_entrypoint **
**********************/
@ -121,25 +119,18 @@ Native_capability Pager_activation_base::cap()
void Pager_entrypoint::dissolve(Pager_object * const o)
{
remove_locked(o);
o->stop_paging();
_activation->Signal_receiver::dissolve(o);
}
Pager_entrypoint::Pager_entrypoint(Cap_session *,
Pager_activation_base * const activation)
:
_activation(activation)
{
_activation->ep(this);
}
: _activation(activation) {
_activation->ep(this); }
Pager_capability Pager_entrypoint::manage(Pager_object * const o)
{
Signal_context_capability scc = _activation->Signal_receiver::manage(o);
Pager_capability p = reinterpret_cap_cast<Pager_object>(scc);
o->start_paging(scc, p);
o->start_paging(_activation->kernel_object());
insert(o);
return p;
return reinterpret_cap_cast<Pager_object>(o->cap());
}

2
repos/base-hw/src/core/platform_thread.cc
View File

@ -214,7 +214,7 @@ void Platform_thread::pager(Pager_object * const pager)
{
typedef Kernel::Thread_event_id Event_id;
if (pager) {
unsigned const sc_id = pager->signal_context_id();
unsigned const sc_id = pager->cap().dst();
if (sc_id) {
if (!Kernel::route_thread_event(kernel_object(), Event_id::FAULT,
sc_id)) {

13
repos/base-hw/src/core/rm_session_support.cc
View File

@ -57,13 +57,13 @@ int Pager_activation_base::apply_mapping()
void Pager_activation_base::entry()
{
/* get ready to receive faults */
_cap = Thread_base::myself()->tid().cap;
_cap_valid.unlock();
_startup_lock.unlock();
while (1)
{
/* receive fault */
Signal s = Signal_receiver::wait_for_signal();
Pager_object * po = static_cast<Pager_object *>(s.context());
if (Kernel::await_signal(_cap.dst())) continue;
Pager_object * po =
*(Pager_object**)Thread_base::myself()->utcb()->base();
/*
* Synchronize access and ensure that the object is still managed
@ -74,9 +74,6 @@ void Pager_activation_base::entry()
Object_pool<Pager_object>::Guard pog(_ep->lookup_and_lock(pon));
if (!pog) continue;
/* let pager object go to fault state */
pog->fault_occured(s);
/* fetch fault data */
Platform_thread * const pt = (Platform_thread *)pog->badge();
if (!pt) {
@ -104,6 +101,6 @@ void Pager_activation_base::entry()
continue;
}
/* let pager object go back to no-fault state */
pog->fault_resolved();
pog->wake_up();
}
}