/** * @file * * This include file defines the per CPU information required * by RTEMS. */ /* * COPYRIGHT (c) 1989-2011. * On-Line Applications Research Corporation (OAR). * * Copyright (c) 2012, 2018 embedded brains GmbH * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at * http://www.rtems.org/license/LICENSE. */ #ifndef _RTEMS_PERCPU_H #define _RTEMS_PERCPU_H #include #if defined( ASM ) #include #else #include #include #include #include #include #include #include #endif #ifdef __cplusplus extern "C" { #endif #if defined(RTEMS_SMP) #if defined(RTEMS_PROFILING) #define PER_CPU_CONTROL_SIZE_APPROX ( 512 + CPU_INTERRUPT_FRAME_SIZE ) #elif defined(RTEMS_DEBUG) || CPU_SIZEOF_POINTER > 4 #define PER_CPU_CONTROL_SIZE_APPROX ( 256 + CPU_INTERRUPT_FRAME_SIZE ) #else #define PER_CPU_CONTROL_SIZE_APPROX ( 128 + CPU_INTERRUPT_FRAME_SIZE ) #endif /* * This ensures that on SMP configurations the individual per-CPU controls * are on different cache lines to prevent false sharing. This define can be * used in assembler code to easily get the per-CPU control for a particular * processor. */ #if PER_CPU_CONTROL_SIZE_APPROX > 1024 #define PER_CPU_CONTROL_SIZE_LOG2 11 #elif PER_CPU_CONTROL_SIZE_APPROX > 512 #define PER_CPU_CONTROL_SIZE_LOG2 10 #elif PER_CPU_CONTROL_SIZE_APPROX > 256 #define PER_CPU_CONTROL_SIZE_LOG2 9 #elif PER_CPU_CONTROL_SIZE_APPROX > 128 #define PER_CPU_CONTROL_SIZE_LOG2 8 #else #define PER_CPU_CONTROL_SIZE_LOG2 7 #endif #define PER_CPU_CONTROL_SIZE ( 1 << PER_CPU_CONTROL_SIZE_LOG2 ) #endif #if !defined( ASM ) struct Record_Control; struct _Thread_Control; struct Scheduler_Context; /** * @defgroup PerCPU RTEMS Per CPU Information * * @ingroup RTEMSScore * * This defines the per CPU state information required by RTEMS * and the BSP. In an SMP configuration, there will be multiple * instances of this data structure -- one per CPU -- and the * current CPU number will be used as the index. */ /**@{*/ #if defined( RTEMS_SMP ) /** * @brief State of a processor. * * The processor state controls the life cycle of processors at the lowest * level. No multi-threading or other high-level concepts matter here. * * State changes must be initiated via _Per_CPU_State_change(). This function * may not return in case someone requested a shutdown. The * _SMP_Send_message() function will be used to notify other processors about * state changes if the other processor is in the up state. * * Due to the sequential nature of the basic system initialization one * processor has a special role. It is the processor executing the boot_card() * function. This processor is called the boot processor. All other * processors are called secondary. * * @dot * digraph states { * i [label="PER_CPU_STATE_INITIAL"]; * rdy [label="PER_CPU_STATE_READY_TO_START_MULTITASKING"]; * reqsm [label="PER_CPU_STATE_REQUEST_START_MULTITASKING"]; * u [label="PER_CPU_STATE_UP"]; * s [label="PER_CPU_STATE_SHUTDOWN"]; * i -> rdy [label="processor\ncompleted initialization"]; * rdy -> reqsm [label="boot processor\ncompleted initialization"]; * reqsm -> u [label="processor\nstarts multitasking"]; * i -> s; * rdy -> s; * reqsm -> s; * u -> s; * } * @enddot */ typedef enum { /** * @brief The per CPU controls are initialized to zero. * * The boot processor executes the sequential boot code in this state. The * secondary processors should perform their basic initialization now and * change into the PER_CPU_STATE_READY_TO_START_MULTITASKING state once this * is complete. */ PER_CPU_STATE_INITIAL, /** * @brief Processor is ready to start multitasking. * * The secondary processor performed its basic initialization and is ready to * receive inter-processor interrupts. Interrupt delivery must be disabled * in this state, but requested inter-processor interrupts must be recorded * and must be delivered once the secondary processor enables interrupts for * the first time. The boot processor will wait for all secondary processors * to change into this state. In case a secondary processor does not reach * this state the system will not start. The secondary processors wait now * for a change into the PER_CPU_STATE_REQUEST_START_MULTITASKING state set * by the boot processor once all secondary processors reached the * PER_CPU_STATE_READY_TO_START_MULTITASKING state. */ PER_CPU_STATE_READY_TO_START_MULTITASKING, /** * @brief Multitasking start of processor is requested. * * The boot processor completed system initialization and is about to perform * a context switch to its heir thread. Secondary processors should now * issue a context switch to the heir thread. This normally enables * interrupts on the processor for the first time. */ PER_CPU_STATE_REQUEST_START_MULTITASKING, /** * @brief Normal multitasking state. */ PER_CPU_STATE_UP, /** * @brief This is the terminal state. */ PER_CPU_STATE_SHUTDOWN } Per_CPU_State; #endif /* defined( RTEMS_SMP ) */ /** * @brief Per-CPU statistics. */ typedef struct { #if defined( RTEMS_PROFILING ) /** * @brief The thread dispatch disabled begin instant in CPU counter ticks. * * This value is used to measure the time of disabled thread dispatching. */ CPU_Counter_ticks thread_dispatch_disabled_instant; /** * @brief The maximum time of disabled thread dispatching in CPU counter * ticks. */ CPU_Counter_ticks max_thread_dispatch_disabled_time; /** * @brief The maximum time spent to process a single sequence of nested * interrupts in CPU counter ticks. * * This is the time interval between the change of the interrupt nest level * from zero to one and the change back from one to zero. */ CPU_Counter_ticks max_interrupt_time; /** * @brief The maximum interrupt delay in CPU counter ticks if supported by * the hardware. */ CPU_Counter_ticks max_interrupt_delay; /** * @brief Count of times when the thread dispatch disable level changes from * zero to one in thread context. * * This value may overflow. */ uint64_t thread_dispatch_disabled_count; /** * @brief Total time of disabled thread dispatching in CPU counter ticks. * * The average time of disabled thread dispatching is the total time of * disabled thread dispatching divided by the thread dispatch disabled * count. * * This value may overflow. */ uint64_t total_thread_dispatch_disabled_time; /** * @brief Count of times when the interrupt nest level changes from zero to * one. * * This value may overflow. */ uint64_t interrupt_count; /** * @brief Total time of interrupt processing in CPU counter ticks. * * The average time of interrupt processing is the total time of interrupt * processing divided by the interrupt count. * * This value may overflow. */ uint64_t total_interrupt_time; #endif /* defined( RTEMS_PROFILING ) */ } Per_CPU_Stats; /** * @brief Per-CPU watchdog header index. */ typedef enum { /** * @brief Index for tick clock per-CPU watchdog header. * * The reference time point for the tick clock is the system start. The * clock resolution is one system clock tick. It is used for the system * clock tick based time services. */ PER_CPU_WATCHDOG_TICKS, /** * @brief Index for realtime clock per-CPU watchdog header. * * The reference time point for the realtime clock is the POSIX Epoch. The * clock resolution is one nanosecond. It is used for the time of day * services and the POSIX services using CLOCK_REALTIME. */ PER_CPU_WATCHDOG_REALTIME, /** * @brief Index for monotonic clock per-CPU watchdog header. * * The reference time point for the monotonic clock is the system start. The * clock resolution is one nanosecond. It is used for the POSIX services * using CLOCK_MONOTONIC. */ PER_CPU_WATCHDOG_MONOTONIC, /** * @brief Count of per-CPU watchdog headers. */ PER_CPU_WATCHDOG_COUNT } Per_CPU_Watchdog_index; /** * @brief Per CPU Core Structure * * This structure is used to hold per core state information. */ typedef struct Per_CPU_Control { #if CPU_PER_CPU_CONTROL_SIZE > 0 /** * @brief CPU port specific control. */ CPU_Per_CPU_control cpu_per_cpu; #endif /** * @brief The interrupt stack low address for this processor. */ void *interrupt_stack_low; /** * @brief The interrupt stack high address for this processor. */ void *interrupt_stack_high; /** * This contains the current interrupt nesting level on this * CPU. */ uint32_t isr_nest_level; /** * @brief Indicetes if an ISR thread dispatch is disabled. * * This flag is context switched with each thread. It indicates that this * thread has an interrupt stack frame on its stack. By using this flag, we * can avoid nesting more interrupt dispatching attempts on a previously * interrupted thread's stack. */ uint32_t isr_dispatch_disable; /** * @brief The thread dispatch critical section nesting counter which is used * to prevent context switches at inopportune moments. */ volatile uint32_t thread_dispatch_disable_level; /** * @brief This is set to true when this processor needs to run the thread * dispatcher. * * It is volatile since interrupts may alter this flag. * * This field is not protected by a lock and must be accessed only by this * processor. Code (e.g. scheduler and post-switch action requests) running * on another processors must use an inter-processor interrupt to set the * thread dispatch necessary indicator to true. * * @see _Thread_Get_heir_and_make_it_executing(). */ volatile bool dispatch_necessary; /* * Ensure that the executing member is at least 4-byte aligned, see * PER_CPU_OFFSET_EXECUTING. This is necessary on CPU ports with relaxed * alignment restrictions, e.g. type alignment is less than the type size. */ bool reserved_for_executing_alignment[ 3 ]; /** * @brief This is the thread executing on this processor. * * This field is not protected by a lock. The only writer is this processor. * * On SMP configurations a thread may be registered as executing on more than * one processor in case a thread migration is in progress. On SMP * configurations use _Thread_Is_executing_on_a_processor() to figure out if * a thread context is executing on a processor. */ struct _Thread_Control *executing; /** * @brief This is the heir thread for this processor. * * This field is not protected by a lock. The only writer after multitasking * start is the scheduler owning this processor. It is assumed that stores * to pointers are atomic on all supported SMP architectures. The CPU port * specific code (inter-processor interrupt handling and * _CPU_SMP_Send_interrupt()) must guarantee that this processor observes the * last value written. * * A thread can be a heir on at most one processor in the system. * * @see _Thread_Get_heir_and_make_it_executing(). */ struct _Thread_Control *heir; #if defined(RTEMS_SMP) CPU_Interrupt_frame Interrupt_frame; #endif /** * @brief The CPU usage timestamp contains the time point of the last heir * thread change or last CPU usage update of the executing thread of this * processor. * * Protected by the scheduler lock. * * @see _Scheduler_Update_heir(), _Thread_Dispatch_update_heir() and * _Thread_Get_CPU_time_used(). */ Timestamp_Control cpu_usage_timestamp; /** * @brief Watchdog state for this processor. */ struct { /** * @brief Protects all watchdog operations on this processor. */ ISR_LOCK_MEMBER( Lock ) /** * @brief Watchdog ticks on this processor used for monotonic clock * watchdogs. */ uint64_t ticks; /** * @brief Header for watchdogs. * * @see Per_CPU_Watchdog_index. */ Watchdog_Header Header[ PER_CPU_WATCHDOG_COUNT ]; } Watchdog; #if defined( RTEMS_SMP ) /** * @brief This lock protects some parts of the low-level thread dispatching. * * We must use a ticket lock here since we cannot transport a local context * through the context switch. * * @see _Thread_Dispatch(). */ SMP_ticket_lock_Control Lock; #if defined( RTEMS_PROFILING ) /** * @brief Lock statistics for the per-CPU lock. */ SMP_lock_Stats Lock_stats; /** * @brief Lock statistics context for the per-CPU lock. */ SMP_lock_Stats_context Lock_stats_context; #endif /** * @brief Chain of threads in need for help. * * This field is protected by the Per_CPU_Control::Lock lock. */ Chain_Control Threads_in_need_for_help; /** * @brief Bit field for SMP messages. * * This bit field is not protected locks. Atomic operations are used to * set and get the message bits. */ Atomic_Ulong message; struct { /** * @brief The scheduler control of the scheduler owning this processor. * * This pointer is NULL in case this processor is currently not used by a * scheduler instance. */ const struct _Scheduler_Control *control; /** * @brief The scheduler context of the scheduler owning this processor. * * This pointer is NULL in case this processor is currently not used by a * scheduler instance. */ const struct Scheduler_Context *context; /** * @brief The idle thread for this processor in case it is online and * currently not used by a scheduler instance. */ struct _Thread_Control *idle_if_online_and_unused; } Scheduler; /** * @brief Begin of the per-CPU data area. * * Contains items defined via PER_CPU_DATA_ITEM(). */ char *data; /** * @brief Indicates the current state of the CPU. * * This field is protected by the _Per_CPU_State_lock lock. * * @see _Per_CPU_State_change(). */ Per_CPU_State state; /** * @brief Action to be executed by this processor in the * SYSTEM_STATE_BEFORE_MULTITASKING state on behalf of the boot processor. * * @see _SMP_Before_multitasking_action(). */ Atomic_Uintptr before_multitasking_action; /** * @brief Indicates if the processor has been successfully started via * _CPU_SMP_Start_processor(). */ bool online; /** * @brief Indicates if the processor is the one that performed the initial * system initialization. */ bool boot; #endif struct Record_Control *record; Per_CPU_Stats Stats; } Per_CPU_Control; #if defined( RTEMS_SMP ) typedef struct { Per_CPU_Control per_cpu; char unused_space_for_cache_line_alignment [ PER_CPU_CONTROL_SIZE - sizeof( Per_CPU_Control ) ]; } Per_CPU_Control_envelope; #else typedef struct { Per_CPU_Control per_cpu; } Per_CPU_Control_envelope; #endif /** * @brief Set of Per CPU Core Information * * This is an array of per CPU core information. */ extern Per_CPU_Control_envelope _Per_CPU_Information[] CPU_STRUCTURE_ALIGNMENT; #if defined( RTEMS_SMP ) #define _Per_CPU_Acquire( cpu ) \ _SMP_ticket_lock_Acquire( \ &( cpu )->Lock, \ &( cpu )->Lock_stats, \ &( cpu )->Lock_stats_context \ ) #else #define _Per_CPU_Acquire( cpu ) \ do { \ (void) ( cpu ); \ } while ( 0 ) #endif #if defined( RTEMS_SMP ) #define _Per_CPU_Release( cpu ) \ _SMP_ticket_lock_Release( \ &( cpu )->Lock, \ &( cpu )->Lock_stats_context \ ) #else #define _Per_CPU_Release( cpu ) \ do { \ (void) ( cpu ); \ } while ( 0 ) #endif #if defined( RTEMS_SMP ) #define _Per_CPU_Acquire_all( isr_cookie ) \ do { \ uint32_t ncpus = _SMP_Get_processor_maximum(); \ uint32_t cpu; \ _ISR_Local_disable( isr_cookie ); \ for ( cpu = 0 ; cpu < ncpus ; ++cpu ) { \ _Per_CPU_Acquire( _Per_CPU_Get_by_index( cpu ) ); \ } \ } while ( 0 ) #else #define _Per_CPU_Acquire_all( isr_cookie ) \ _ISR_Local_disable( isr_cookie ) #endif #if defined( RTEMS_SMP ) #define _Per_CPU_Release_all( isr_cookie ) \ do { \ uint32_t ncpus = _SMP_Get_processor_maximum(); \ uint32_t cpu; \ for ( cpu = 0 ; cpu < ncpus ; ++cpu ) { \ _Per_CPU_Release( _Per_CPU_Get_by_index( cpu ) ); \ } \ _ISR_Local_enable( isr_cookie ); \ } while ( 0 ) #else #define _Per_CPU_Release_all( isr_cookie ) \ _ISR_Local_enable( isr_cookie ) #endif /* * If we get the current processor index in a context which allows thread * dispatching, then we may already run on another processor right after the * read instruction. There are very few cases in which this makes sense (here * we can use _Per_CPU_Get_snapshot()). All other places must use * _Per_CPU_Get() so that we can add checks for RTEMS_DEBUG. */ #if defined( _CPU_Get_current_per_CPU_control ) #define _Per_CPU_Get_snapshot() _CPU_Get_current_per_CPU_control() #else #define _Per_CPU_Get_snapshot() \ ( &_Per_CPU_Information[ _SMP_Get_current_processor() ].per_cpu ) #endif #if defined( RTEMS_SMP ) static inline Per_CPU_Control *_Per_CPU_Get( void ) { Per_CPU_Control *cpu_self = _Per_CPU_Get_snapshot(); _Assert( cpu_self->thread_dispatch_disable_level != 0 || _ISR_Get_level() != 0 ); return cpu_self; } #else #define _Per_CPU_Get() _Per_CPU_Get_snapshot() #endif static inline Per_CPU_Control *_Per_CPU_Get_by_index( uint32_t index ) { return &_Per_CPU_Information[ index ].per_cpu; } static inline uint32_t _Per_CPU_Get_index( const Per_CPU_Control *cpu ) { const Per_CPU_Control_envelope *per_cpu_envelope = ( const Per_CPU_Control_envelope * ) cpu; return ( uint32_t ) ( per_cpu_envelope - &_Per_CPU_Information[ 0 ] ); } static inline struct _Thread_Control *_Per_CPU_Get_executing( const Per_CPU_Control *cpu ) { return cpu->executing; } static inline bool _Per_CPU_Is_processor_online( const Per_CPU_Control *cpu ) { #if defined( RTEMS_SMP ) return cpu->online; #else (void) cpu; return true; #endif } static inline bool _Per_CPU_Is_boot_processor( const Per_CPU_Control *cpu ) { #if defined( RTEMS_SMP ) return cpu->boot; #else (void) cpu; return true; #endif } #if defined( RTEMS_SMP ) /** * @brief Allocate and Initialize Per CPU Structures * * This method allocates and initialize the per CPU structure. */ void _Per_CPU_Initialize(void); void _Per_CPU_State_change( Per_CPU_Control *cpu, Per_CPU_State new_state ); /** * @brief Waits for a processor to change into a non-initial state. * * This function should be called only in _CPU_SMP_Start_processor() if * required by the CPU port or BSP. * * @code * bool _CPU_SMP_Start_processor(uint32_t cpu_index) * { * uint32_t timeout = 123456; * * start_the_processor(cpu_index); * * return _Per_CPU_State_wait_for_non_initial_state(cpu_index, timeout); * } * @endcode * * @param[in] cpu_index The processor index. * @param[in] timeout_in_ns The timeout in nanoseconds. Use a value of zero to * wait forever if necessary. * * @retval true The processor is in a non-initial state. * @retval false The timeout expired before the processor reached a non-initial * state. */ bool _Per_CPU_State_wait_for_non_initial_state( uint32_t cpu_index, uint32_t timeout_in_ns ); #endif /* defined( RTEMS_SMP ) */ /* * On a non SMP system, the _SMP_Get_current_processor() is defined to 0. * Thus when built for non-SMP, there should be no performance penalty. */ #define _Thread_Dispatch_disable_level \ _Per_CPU_Get()->thread_dispatch_disable_level #define _Thread_Heir \ _Per_CPU_Get()->heir #if defined(_CPU_Get_thread_executing) #define _Thread_Executing \ _CPU_Get_thread_executing() #else #define _Thread_Executing \ _Per_CPU_Get_executing( _Per_CPU_Get() ) #endif #define _ISR_Nest_level \ _Per_CPU_Get()->isr_nest_level #define _CPU_Interrupt_stack_low \ _Per_CPU_Get()->interrupt_stack_low #define _CPU_Interrupt_stack_high \ _Per_CPU_Get()->interrupt_stack_high #define _Thread_Dispatch_necessary \ _Per_CPU_Get()->dispatch_necessary /** * @brief Returns the thread control block of the executing thread. * * This function can be called in any thread context. On SMP configurations, * interrupts are disabled to ensure that the processor index is used * consistently if no CPU port specific method is available to get the * executing thread. * * @return The thread control block of the executing thread. */ RTEMS_INLINE_ROUTINE struct _Thread_Control *_Thread_Get_executing( void ) { struct _Thread_Control *executing; #if defined(RTEMS_SMP) && !defined(_CPU_Get_thread_executing) ISR_Level level; _ISR_Local_disable( level ); #endif executing = _Thread_Executing; #if defined(RTEMS_SMP) && !defined(_CPU_Get_thread_executing) _ISR_Local_enable( level ); #endif return executing; } /**@}*/ #endif /* !defined( ASM ) */ #if defined( ASM ) || defined( _RTEMS_PERCPU_DEFINE_OFFSETS ) #define PER_CPU_INTERRUPT_STACK_LOW \ CPU_PER_CPU_CONTROL_SIZE #define PER_CPU_INTERRUPT_STACK_HIGH \ PER_CPU_INTERRUPT_STACK_LOW + CPU_SIZEOF_POINTER #define INTERRUPT_STACK_LOW \ (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_LOW) #define INTERRUPT_STACK_HIGH \ (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_HIGH) /* * These are the offsets of the required elements in the per CPU table. */ #define PER_CPU_ISR_NEST_LEVEL \ PER_CPU_INTERRUPT_STACK_HIGH + CPU_SIZEOF_POINTER #define PER_CPU_ISR_DISPATCH_DISABLE \ PER_CPU_ISR_NEST_LEVEL + 4 #define PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL \ PER_CPU_ISR_DISPATCH_DISABLE + 4 #define PER_CPU_DISPATCH_NEEDED \ PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL + 4 #define PER_CPU_OFFSET_EXECUTING \ PER_CPU_DISPATCH_NEEDED + 4 #define PER_CPU_OFFSET_HEIR \ PER_CPU_OFFSET_EXECUTING + CPU_SIZEOF_POINTER #if defined(RTEMS_SMP) #define PER_CPU_INTERRUPT_FRAME_AREA \ PER_CPU_OFFSET_HEIR + CPU_SIZEOF_POINTER #endif #define THREAD_DISPATCH_DISABLE_LEVEL \ (SYM(_Per_CPU_Information) + PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL) #define ISR_NEST_LEVEL \ (SYM(_Per_CPU_Information) + PER_CPU_ISR_NEST_LEVEL) #define DISPATCH_NEEDED \ (SYM(_Per_CPU_Information) + PER_CPU_DISPATCH_NEEDED) #endif /* defined( ASM ) || defined( _RTEMS_PERCPU_DEFINE_OFFSETS ) */ #ifdef __cplusplus } #endif #endif /* end of include file */