genode/base/include/cpu_session/cpu_session.h
Norman Feske 83bdfea9b0 Extend Cpu_session with thread-affinity API
This patch introduces the functions 'affinity' and 'num_cpus' to the CPU
session interface. The interface extension will allow the assignment of
individual threads to CPUs. At this point, it is just a stub with no
actual platform support.
2012-09-05 10:25:04 +02:00

259 lines
8.5 KiB
C++

/*
* \brief CPU (processing time) manager session interface
* \author Christian Helmuth
* \date 2006-06-27
*
* :Question:
*
* Why are thread operations not methods of the thread but
* methods of the CPU session?
*
* :Answer:
*
* This enables the CPU session to impose policies on thread
* operations. These policies are based on the session
* construction arguments. If thread operations would be
* provided as thread methods, Thread would need to consult
* its container object (its CPU session) about the authorization
* of each operation and, thereby, would introduce a circular
* dependency between CPU session and Thread.
*/
/*
* Copyright (C) 2006-2012 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.
*/
#ifndef _INCLUDE__CPU_SESSION__CPU_SESSION_H_
#define _INCLUDE__CPU_SESSION__CPU_SESSION_H_
#include <base/stdint.h>
#include <base/exception.h>
#include <base/thread_state.h>
#include <base/rpc_args.h>
#include <base/signal.h>
#include <thread/capability.h>
#include <pager/capability.h>
#include <session/session.h>
#include <ram_session/ram_session.h>
namespace Genode {
struct Cpu_session : Session
{
/*********************
** Exception types **
*********************/
class Thread_creation_failed : public Exception { };
static const char *service_name() { return "CPU"; }
enum { THREAD_NAME_LEN = 48 };
enum { PRIORITY_LIMIT = 1 << 16 };
enum { DEFAULT_PRIORITY = 0 };
typedef Rpc_in_buffer<THREAD_NAME_LEN> Name;
virtual ~Cpu_session() { }
/**
* Create a new thread
*
* \param name name for the thread
* \param utcb Base of the UTCB that will be used by the thread
* \return capability representing the new thread
* \throw Thread_creation_failed
*/
virtual Thread_capability create_thread(Name const &name,
addr_t utcb = 0) = 0;
/**
* Get dataspace of the UTCB that is used by the specified thread
*/
virtual Ram_dataspace_capability utcb(Thread_capability thread) = 0;
/**
* Kill an existing thread
*
* \param thread capability of the thread to kill
*/
virtual void kill_thread(Thread_capability thread) = 0;
/**
* Retrieve thread list of CPU session
*
* The next() function returns an invalid capability if the
* specified thread does not exists or if it is the last one
* of the CPU session.
*/
virtual Thread_capability first() = 0;
virtual Thread_capability next(Thread_capability curr) = 0;
/**
* Set paging capabilities for thread
*
* \param thread thread to configure
* \param pager capability used to propagate page faults
*/
virtual int set_pager(Thread_capability thread,
Pager_capability pager) = 0;
/**
* Modify instruction and stack pointer of thread - start the
* thread
*
* \param thread thread to start
* \param ip initial instruction pointer
* \param sp initial stack pointer
*
* \return 0 on success
*/
virtual int start(Thread_capability thread, addr_t ip, addr_t sp) = 0;
/**
* Pause the specified thread
*
* After calling this function, the execution of the thread can be
* continued by calling 'resume'.
*/
virtual void pause(Thread_capability thread) = 0;
/**
* Resume the specified thread
*/
virtual void resume(Thread_capability thread) = 0;
/**
* Cancel a currently blocking operation
*
* \param thread thread to unblock
*/
virtual void cancel_blocking(Thread_capability thread) = 0;
/**
* Return thread state
*
* \param thread thread to spy on
* \param state_dst result
*
* \return 0 on success
*/
virtual int state(Thread_capability thread,
Thread_state *state_dst) = 0;
/**
* Register signal handler for exceptions of the specified thread
*/
virtual void exception_handler(Thread_capability thread,
Signal_context_capability handler) = 0;
/**
* Enable/disable single stepping for specified thread.
*
* Since this functions is currently supported by a small number of
* platforms, we provide a default implementation
*
* \param thread thread to set into single step mode
* \param enable true = enable single-step mode; false = disable
*/
virtual void single_step(Thread_capability thread, bool enable) {}
/**
* Return number of CPUs available via the CPU session
*/
virtual unsigned num_cpus() const = 0;
/**
* Assign thread to a CPU
*
* The 'cpu' argument is a CPU index starting at 0. It must be
* smaller than the value returned by 'num_cpus()'.
*/
virtual void affinity(Thread_capability thread, unsigned cpu) = 0;
/**
* Translate generic priority value to kernel-specific priority levels
*
* \param pf_prio_limit maximum priority used for the kernel, must
* be power of 2
* \param prio generic priority value as used by the CPU
* session interface
* \param inverse order of platform priorities, if true
* 'pf_prio_limit' corresponds to the highest
* priority, otherwise it refers to the
* lowest priority.
* \return platform-specific priority value
*/
static unsigned scale_priority(unsigned pf_prio_limit, unsigned prio,
bool inverse = true)
{
/* if no priorities are used, use the platform priority limit */
if (prio == 0) return pf_prio_limit;
/*
* Generic priority values are (0 is highest, 'PRIORITY_LIMIT'
* is lowest. On platforms where priority levels are defined
* the other way round, we have to invert the priority value.
*/
prio = inverse ? Cpu_session::PRIORITY_LIMIT - prio : prio;
/* scale value to platform priority range 0..pf_prio_limit */
return (prio*pf_prio_limit)/Cpu_session::PRIORITY_LIMIT;
}
/*********************
** RPC declaration **
*********************/
GENODE_RPC_THROW(Rpc_create_thread, Thread_capability, create_thread,
GENODE_TYPE_LIST(Thread_creation_failed),
Name const &, addr_t);
GENODE_RPC(Rpc_utcb, Ram_dataspace_capability, utcb, Thread_capability);
GENODE_RPC(Rpc_kill_thread, void, kill_thread, Thread_capability);
GENODE_RPC(Rpc_first, Thread_capability, first,);
GENODE_RPC(Rpc_next, Thread_capability, next, Thread_capability);
GENODE_RPC(Rpc_set_pager, int, set_pager, Thread_capability, Pager_capability);
GENODE_RPC(Rpc_start, int, start, Thread_capability, addr_t, addr_t);
GENODE_RPC(Rpc_pause, void, pause, Thread_capability);
GENODE_RPC(Rpc_resume, void, resume, Thread_capability);
GENODE_RPC(Rpc_cancel_blocking, void, cancel_blocking, Thread_capability);
GENODE_RPC(Rpc_state, int, state, Thread_capability, Thread_state *);
GENODE_RPC(Rpc_exception_handler, void, exception_handler,
Thread_capability, Signal_context_capability);
GENODE_RPC(Rpc_single_step, void, single_step, Thread_capability, bool);
GENODE_RPC(Rpc_num_cpus, unsigned, num_cpus);
GENODE_RPC(Rpc_affinity, void, affinity, Thread_capability, unsigned);
/*
* 'GENODE_RPC_INTERFACE' declaration done manually
*
* The number of RPC function of this interface exceeds the maximum
* number of elements supported by 'Meta::Type_list'. Therefore, we
* construct the type list by hand using nested type tuples instead
* of employing the convenience macro 'GENODE_RPC_INTERFACE'.
*/
typedef Meta::Type_tuple<Rpc_create_thread,
Meta::Type_tuple<Rpc_utcb,
Meta::Type_tuple<Rpc_kill_thread,
Meta::Type_tuple<Rpc_first,
Meta::Type_tuple<Rpc_next,
Meta::Type_tuple<Rpc_set_pager,
Meta::Type_tuple<Rpc_start,
Meta::Type_tuple<Rpc_pause,
Meta::Type_tuple<Rpc_resume,
Meta::Type_tuple<Rpc_cancel_blocking,
Meta::Type_tuple<Rpc_state,
Meta::Type_tuple<Rpc_exception_handler,
Meta::Type_tuple<Rpc_single_step,
Meta::Type_tuple<Rpc_num_cpus,
Meta::Type_tuple<Rpc_affinity,
Meta::Empty>
> > > > > > > > > > > > > > Rpc_functions;
};
}
#endif /* _INCLUDE__CPU_SESSION__CPU_SESSION_H_ */