pci: support shared irqs (x86)

Step to move shared irq handling out of core in the long run. So, use
irq_proxy implementation from base in os and implement shared irq handling
in platform driver of x86 (pci_drv).

Fixes #1471

repos/os/include/platform/irq_proxy.h

@@ -0,0 +1,242 @@
+/**
+ * \brief  Shared-interrupt support
+ * \author Christian Helmuth
+ * \author Sebastian Sumpf
+ * \date   2009-12-15
+ */
+
+#ifndef _CORE__INCLUDE__IRQ_PROXY_H_
+#define _CORE__INCLUDE__IRQ_PROXY_H_
+
+#include <base/env.h>
+
+
+namespace Genode {
+	class Irq_sigh;
+	template <typename THREAD> class Irq_proxy;
+}
+
+
+class Genode::Irq_sigh : public Genode::Signal_context_capability,
+                         public Genode::List<Genode::Irq_sigh>::Element
+{
+	public:
+
+		inline Irq_sigh * operator= (const Signal_context_capability &cap)
+		{
+			Signal_context_capability::operator=(cap);
+			return this;
+		}
+
+		Irq_sigh() { }
+
+		void notify() { Genode::Signal_transmitter(*this).submit(1); }
+};
+
+
+/*
+ * Proxy thread that associates to the interrupt and unblocks waiting irqctrl
+ * threads.
+ *
+ * XXX resources are not accounted as the interrupt is shared
+ */
+template <typename THREAD>
+class Genode::Irq_proxy : public THREAD,
+                          public Genode::List<Genode::Irq_proxy<THREAD> >::Element
+{
+	protected:
+
+		char              _name[32];
+		Lock              _startup_lock;
+
+		long              _irq_number;
+
+		Lock              _mutex;             /* protects this object */
+		int               _num_sharers;       /* number of clients sharing this IRQ */
+		Semaphore         _sleep;             /* wake me up if aspired blockers return */
+		List<Irq_sigh>    _sigh_list;
+		int               _num_acknowledgers; /* number of currently blocked clients */
+		bool              _woken_up;          /* client decided to wake me up -
+		                                         this prevents multiple wakeups
+		                                         to happen during initialization */
+
+
+		/***************
+		 ** Interface **
+		 ***************/
+
+		/**
+		 * Request interrupt
+		 *
+		 * \return  true on success
+		 */
+		virtual bool _associate() = 0;
+
+		/**
+		 * Wait for associated interrupt
+		 */
+		virtual void _wait_for_irq() = 0;
+
+		/**
+		 * Acknowledge interrupt
+		 */
+		virtual void _ack_irq() = 0;
+
+		/********************
+		 ** Implementation **
+		 ********************/
+
+		const char *_construct_name(long irq_number)
+		{
+			snprintf(_name, sizeof(_name), "irqproxy%02lx", irq_number);
+			return _name;
+		}
+
+		void _loop()
+		{
+			/* wait for first blocker */
+			_sleep.down();
+
+			while (1) {
+				_wait_for_irq();
+
+				/* notify all */
+				notify_about_irq(1);
+
+				/*
+				 * We must wait for all clients to ack their interrupt,
+				 * otherwise level-triggered interrupts will occur immediately
+				 * after acknowledgement. That's an inherent security problem
+				 * with shared IRQs and induces problems with dynamic driver
+				 * load and unload.
+				 */
+				_sleep.down();
+
+				/* acknowledge previous interrupt */
+				_ack_irq();
+			}
+		}
+
+		/**
+		 * Start this thread, should be called externally from derived class
+		 */
+		virtual void _start()
+		{
+			THREAD::start();
+			_startup_lock.lock();
+		}
+
+	public:
+
+		Irq_proxy(long irq_number)
+		:
+			THREAD(_construct_name(irq_number)),
+			_startup_lock(Lock::LOCKED), _irq_number(irq_number),
+			_mutex(Lock::UNLOCKED), _num_sharers(0), _num_acknowledgers(0), _woken_up(false)
+
+		{ }
+
+		/**
+		 * Thread interface
+		 */
+		void entry()
+		{
+			bool const associate_suceeded = _associate();
+
+			_startup_lock.unlock();
+
+			if (associate_suceeded)
+				_loop();
+		}
+
+		/**
+		 * Acknowledgements of clients
+		 */
+		virtual bool ack_irq()
+		{
+			Lock::Guard lock_guard(_mutex);
+
+			_num_acknowledgers++;
+
+			/*
+			 * The proxy thread has to be woken up if no client woke it up
+			 * before and this client is the last aspired acknowledger.
+			 */
+			if (!_woken_up && _num_acknowledgers == _num_sharers) {
+				_sleep.up();
+				_woken_up = true;
+			}
+
+			return _woken_up;
+		}
+
+		/**
+		 * Notify all clients about irq
+		 */
+		void notify_about_irq(unsigned)
+		{
+			Lock::Guard lock_guard(_mutex);
+
+			/* reset acknowledger state */
+			_num_acknowledgers = 0;
+			_woken_up          = false;
+
+			/* inform blocked clients */
+			for (Irq_sigh * s = _sigh_list.first(); s ; s = s->next())
+				s->notify();
+		}
+
+		long irq_number() const { return _irq_number; }
+
+		virtual bool add_sharer(Irq_sigh *s)
+		{
+			Lock::Guard lock_guard(_mutex);
+
+			++_num_sharers;
+			_sigh_list.insert(s);
+
+			return true;
+		}
+
+		virtual bool remove_sharer(Irq_sigh *s)
+		{
+			Lock::Guard lock_guard(_mutex);
+
+			_sigh_list.remove(s);
+			--_num_sharers;
+
+			if (_woken_up)
+				return _num_sharers == 0;
+
+			if (_num_acknowledgers == _num_sharers) {
+				_sleep.up();
+				_woken_up = true;
+			}
+
+			return _num_sharers == 0;
+		}
+
+		template <typename PROXY>
+		static PROXY *get_irq_proxy(long irq_number, Range_allocator *irq_alloc = 0)
+		{
+			static List<Irq_proxy> proxies;
+			static Lock            proxies_lock;
+
+			Lock::Guard lock_guard(proxies_lock);
+
+			/* lookup proxy in database */
+			for (Irq_proxy *p = proxies.first(); p; p = p->next())
+				if (p->irq_number() == irq_number)
+					return static_cast<PROXY *>(p);
+
+			/* try to create proxy */
+			if (!irq_alloc || irq_alloc->alloc_addr(1, irq_number).is_error())
+				return 0;
+
+			PROXY *new_proxy = new (env()->heap()) PROXY(irq_number);
+			proxies.insert(new_proxy);
+			return new_proxy;
+		}
+};
+
+#endif /* _CORE__INCLUDE__IRQ_PROXY_H_ */

repos/os/src/drivers/pci/irq.cc

@@ -0,0 +1,241 @@
+/*
+ * \brief  Implementation of shared IRQs in PCI driver
+ * \author Alexander Boettcher
+ * \date   2015-03-27
+ */
+
+/*
+ * Copyright (C) 2015 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+/* Genode includes */
+#include <base/printf.h>
+#include <irq_session/connection.h>
+
+/* Genode OS includes */
+#include <platform/irq_proxy.h>
+
+/* PCI driver include */
+#include "irq.h"
+
+
+namespace Pci {
+	class Irq_component;
+	class Irq_allocator;
+	class Irq_thread;
+}
+
+
+using namespace Genode;
+
+
+/**
+ * A simple range allocator implementation used by the Irq_proxy
+ */
+class Pci::Irq_allocator : public Range_allocator, Bit_allocator<256>
+{
+	Alloc_return alloc_addr(size_t size, addr_t addr) override
+	{
+		try {
+			_array.set(addr, size);
+			return Alloc_return::OK;
+		} catch (...) {
+			return Alloc_return::RANGE_CONFLICT;
+		}
+	}
+
+	/* unused methods */
+	int    remove_range(addr_t, size_t) override { return 0; }
+	int    add_range(addr_t, size_t)    override { return 0; }
+	bool   valid_addr(addr_t)     const override { return false; }
+	size_t avail()                const override { return 0; }
+	bool   alloc(size_t, void **)       override { return false; }
+	void   free(void *)                 override { }
+	void   free(void *, size_t)         override { }
+	size_t overhead(size_t)       const override { return 0; }
+	bool   need_size_for_free()   const override { return 0; }
+
+	Alloc_return alloc_aligned(size_t, void **, int, addr_t, addr_t) override {
+		 return Alloc_return::RANGE_CONFLICT; }
+};
+
+
+/**
+ * Required by Irq_proxy if we would like to have a thread per IRQ,
+ * which we don't want to in the PCI driver - one thread is sufficient.
+ */
+class NoThread
+{
+	public:
+
+		NoThread(const char *) { }
+
+		void start(void) { }
+};
+
+
+/**
+ * Thread waiting for signals caused by IRQs 
+ */
+class Pci::Irq_thread : public Genode::Thread<4096>
+{
+	private:
+
+		Signal_receiver _sig_rec;
+
+	public:
+
+		Irq_thread() : Thread<4096>("irq_sig_recv") { start(); }
+
+		Signal_receiver & sig_rec() { return _sig_rec; }
+
+		void entry() {
+
+			typedef Genode::Signal_dispatcher_base Sdb;
+
+			while (1) {
+				Genode::Signal sig = _sig_rec.wait_for_signal();
+
+				Sdb *dispatcher = dynamic_cast<Sdb *>(sig.context());
+
+				if (!dispatcher) {
+					PERR("dispatcher missing for signal %p, %u",
+					     sig.context(), sig.num());
+					continue;
+				}
+				dispatcher->dispatch(sig.num());
+			}
+		}
+};
+
+
+/**
+ * One allocator for managing in use IRQ numbers and one IRQ thread waiting
+ * for Genode signals of all hardware IRQs.
+ */
+static Pci::Irq_allocator irq_alloc;
+static Pci::Irq_thread    irq_thread;
+
+
+/**
+ * Irq_proxy interface implementation
+ */
+typedef Genode::Irq_proxy<NoThread> Proxy;
+
+class Pci::Irq_component : public Proxy
+{
+	private:
+
+		Genode::Irq_connection _irq;
+		Genode::Signal_dispatcher<Pci::Irq_component> _irq_dispatcher;
+
+		bool _associated;
+
+	public:
+
+		void _ack_irq() {
+			/*
+			 * Associate handler only when required, because our partner may
+			 * also implement shared irq and would expect to get ack_irq()
+			 * form us even if we have no client ...
+			 */
+			if (!_associated) {
+				_associated = true;
+				/* register signal handler on irq_session */
+				_irq.sigh(_irq_dispatcher);
+			}
+
+			_irq.ack_irq();
+		}
+
+		bool _associate()    { return _associated; }
+		void _wait_for_irq() { }
+
+		virtual bool remove_sharer(Irq_sigh *s) override {
+			if (!Proxy::remove_sharer(s))
+				return false;
+
+			/* De-associate handler. */
+			_associated = false;
+			_irq.sigh(Genode::Signal_context_capability());
+			return true;
+		}
+
+	public:
+
+		Irq_component(unsigned gsi)
+		:
+			Proxy(gsi), _irq(gsi), _irq_dispatcher(irq_thread.sig_rec(), *this,
+			                                       &::Proxy::notify_about_irq),
+			_associated(false)
+		{ }
+};
+
+
+
+/*******************************
+ ** PCI IRQ session component **
+ *******************************/
+
+void Pci::Irq_session_component::ack_irq()
+{
+	Irq_component *irq_obj = Proxy::get_irq_proxy<Irq_component>(_gsi);
+	if (!irq_obj) {
+		PERR("Expected to find IRQ proxy for IRQ %02x", _gsi);
+		return;
+	}
+
+	if (irq_obj->ack_irq())
+		irq_obj->_ack_irq();
+}
+
+
+Pci::Irq_session_component::Irq_session_component(unsigned irq) : _gsi(irq)
+{
+	bool valid = false;
+
+	/* invalid irq number for pci devices */
+	if (irq == 0xFF)
+		return;
+
+	try {
+		/* check if IRQ object was used before */
+		valid = Proxy::get_irq_proxy<Irq_component>(_gsi, &irq_alloc);
+	} catch (Genode::Parent::Service_denied) { }
+
+	if (!valid)
+		PERR("unavailable IRQ object 0x%x requested", _gsi);
+}
+
+
+Pci::Irq_session_component::~Irq_session_component()
+{
+	Irq_component *irq_obj = Proxy::get_irq_proxy<Irq_component>(_gsi);
+	if (!irq_obj) return;
+
+	if (_irq_sigh.valid())
+		irq_obj->remove_sharer(&_irq_sigh);
+}
+
+
+void Pci::Irq_session_component::sigh(Genode::Signal_context_capability sigh)
+{
+	Irq_component *irq_obj = Proxy::get_irq_proxy<Irq_component>(_gsi);
+	if (!irq_obj) {
+		PERR("signal handler got not registered - irq object unavailable");
+		return;
+	}
+
+	Genode::Signal_context_capability old = _irq_sigh;
+
+	if (old.valid() && !sigh.valid())
+		irq_obj->remove_sharer(&_irq_sigh);
+
+	_irq_sigh = sigh;
+
+	if (!old.valid() && sigh.valid())
+		irq_obj->add_sharer(&_irq_sigh);
+}

repos/os/src/drivers/pci/irq.h

@@ -0,0 +1,49 @@
+/*
+ * \brief  IRQ session interface
+ * \author Alexander Boettcher
+ * \date   2015-03-25
+ */
+
+/*
+ * Copyright (C) 2015 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#pragma once
+
+#include <base/rpc_server.h>
+
+#include <util/list.h>
+
+#include <irq_session/irq_session.h>
+#include <irq_session/capability.h>
+
+/* PCI local includes */
+#include <platform/irq_proxy.h>
+
+
+namespace Pci { class Irq_session_component; }
+
+
+class Pci::Irq_session_component : public Genode::Rpc_object<Genode::Irq_session>,
+                                   public Genode::List<Irq_session_component>::Element
+{
+	private:
+
+		unsigned         _gsi;
+		Genode::Irq_sigh _irq_sigh;
+
+	public:
+
+		Irq_session_component(unsigned);
+		~Irq_session_component();
+
+		/***************************
+		 ** Irq session interface **
+		 ***************************/
+
+		void               ack_irq() override;
+		void               sigh(Genode::Signal_context_capability) override;
+};

repos/os/src/drivers/pci/pci_device_component.h

@@ -20,106 +20,111 @@
 #include <base/printf.h>
 
 #include <io_mem_session/io_mem_session.h>
-#include <irq_session/connection.h>
 
 #include "pci_device_config.h"
 
-namespace Pci {
+#include "irq.h"
 
-	class Device_component : public Genode::Rpc_object<Device>,
-	                         public Genode::List<Device_component>::Element
-	{
-		private:
+namespace Pci { class Device_component; }
 
-			Device_config              _device_config;
-			Genode::addr_t             _config_space;
-			Genode::Io_mem_connection *_io_mem;
-			Config_access              _config_access;
-			Genode::Irq_connection     _irq;
+class Pci::Device_component : public Genode::Rpc_object<Pci::Device>,
+                              public Genode::List<Device_component>::Element
+{
+	private:
 
-			enum { PCI_IRQ = 0x3c };
+		Device_config              _device_config;
+		Genode::addr_t             _config_space;
+		Genode::Io_mem_connection *_io_mem;
+		Config_access              _config_access;
+		Genode::Rpc_entrypoint    *_ep;
+		Irq_session_component      _irq_session;
 
-		public:
+		enum { PCI_IRQ = 0x3c };
 
-			/**
-			 * Constructor
+	public:
+
+		/**
+		 * Constructor
+		 */
+		Device_component(Device_config device_config, Genode::addr_t addr,
+		                 Genode::Rpc_entrypoint *ep)
+		:
+			_device_config(device_config), _config_space(addr),
+			_io_mem(0), _ep(ep),
+			_irq_session(_device_config.read(&_config_access, PCI_IRQ,
+			                                 Pci::Device::ACCESS_8BIT))
+		{
+			_ep->manage(&_irq_session);
+		}
+
+		/**
+		 * De-constructor
+		 */
+		~Device_component()
+		{
+			_ep->dissolve(&_irq_session);
+		}
+
+		/****************************************
+		 ** Methods used solely by pci session **
+		 ****************************************/
+
+		Device_config config() { return _device_config; }
+
+		Genode::addr_t config_space() { return _config_space; }
+
+		void set_config_space(Genode::Io_mem_connection * io_mem) {
+			_io_mem = io_mem; }
+
+		Genode::Io_mem_connection * get_config_space() { return _io_mem; }
+
+		/**************************
+		 ** PCI-device interface **
+		 **************************/
+
+		void bus_address(unsigned char *bus, unsigned char *dev,
+		                 unsigned char *fn)
+		{
+			*bus = _device_config.bus_number();
+			*dev = _device_config.device_number();
+			*fn  = _device_config.function_number();
+		}
+
+		unsigned short vendor_id() { return _device_config.vendor_id(); }
+
+		unsigned short device_id() { return _device_config.device_id(); }
+
+		unsigned class_code() { return _device_config.class_code(); }
+
+		Resource resource(int resource_id)
+		{
+			/* return invalid resource if device is invalid */
+			if (!_device_config.valid())
+				Resource(0, 0);
+
+			return _device_config.resource(resource_id);
+		}
+
+		unsigned config_read(unsigned char address, Access_size size)
+		{
+			return _device_config.read(&_config_access, address, size);
+		}
+
+		void config_write(unsigned char address, unsigned value, Access_size size)
+		{
+			/*
+			 * XXX implement policy to prevent write access to base-address registers
 			 */
-			Device_component(Device_config device_config, Genode::addr_t addr)
-			:
-				_device_config(device_config), _config_space(addr),
-				_io_mem(0),
-				_irq(_device_config.read(&_config_access, PCI_IRQ,
-				                         Pci::Device::ACCESS_8BIT))
-			{ }
 
-			/****************************************
-			 ** Methods used solely by pci session **
-			 ****************************************/
+			_device_config.write(&_config_access, address, value, size);
+		}
 
-			Device_config config() { return _device_config; }
-
-			Genode::addr_t config_space() { return _config_space; }
-
-			void set_config_space(Genode::Io_mem_connection * io_mem) {
-				_io_mem = io_mem; }
-
-			Genode::Io_mem_connection * get_config_space() { return _io_mem; }
-
-			/**************************
-			 ** PCI-device interface **
-			 **************************/
-
-			void bus_address(unsigned char *bus, unsigned char *dev,
-			                 unsigned char *fn)
-			{
-				*bus = _device_config.bus_number();
-				*dev = _device_config.device_number();
-				*fn  = _device_config.function_number();
-			}
-
-			unsigned short vendor_id() {
-				return _device_config.vendor_id(); }
-
-			unsigned short device_id() {
-				return _device_config.device_id(); }
-
-			unsigned class_code() {
-				return _device_config.class_code(); }
-
-			Resource resource(int resource_id)
-			{
-				/* return invalid resource if device is invalid */
-				if (!_device_config.valid())
-					Resource(0, 0);
-
-				return _device_config.resource(resource_id);
-			}
-
-			unsigned config_read(unsigned char address, Access_size size)
-			{
-				Config_access config_access;
-
-				return _device_config.read(&config_access, address, size);
-			}
-
-			void config_write(unsigned char address, unsigned value, Access_size size)
-			{
-				Config_access config_access;
-
-				/*
-				 * XXX implement policy to prevent write access to base-address registers
-				 */
-
-				_device_config.write(&config_access, address, value, size);
-			}
-
-			Genode::Irq_session_capability irq(Genode::uint8_t id) override
-			{
-				if (id != 0)
-					return Genode::Irq_session_capability();
-				return _irq_session.cap();
-			}
-	};
-}
+		Genode::Irq_session_capability irq(Genode::uint8_t id) override
+		{
+			if (id != 0)
+				return Genode::Irq_session_capability();
+			return _irq_session.cap();
+		}
+};
 
 #endif /* _PCI_DEVICE_COMPONENT_H_ */

repos/os/src/drivers/pci/pci_session_component.h

@@ -253,7 +253,7 @@ namespace Pci {
 				 * FIXME: check and adjust session quota
 				 */
 				Device_component *device_component =
-					new (_md_alloc) Device_component(config, config_space);
+					new (_md_alloc) Device_component(config, config_space, _ep);
 
 				if (!device_component)
 					return Device_capability();

repos/os/src/drivers/pci/x86/target.mk

@@ -1,8 +1,8 @@
 TARGET   = pci_drv
 REQUIRES = x86
-SRC_CC   = main.cc
+SRC_CC   = main.cc irq.cc
 LIBS     = base config
 
 INC_DIR  = $(PRG_DIR)/..
 
-vpath main.cc $(PRG_DIR)/..
+vpath %.cc $(PRG_DIR)/..