139 lines
4.1 KiB
ReStructuredText
139 lines
4.1 KiB
ReStructuredText
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.. SPDX-License-Identifier: GPL-2.0
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=======
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spu_run
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=======
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Name
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====
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spu_run - execute an spu context
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Synopsis
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========
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::
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#include <sys/spu.h>
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int spu_run(int fd, unsigned int *npc, unsigned int *event);
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Description
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===========
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The spu_run system call is used on PowerPC machines that implement the
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Cell Broadband Engine Architecture in order to access Synergistic Pro-
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cessor Units (SPUs). It uses the fd that was returned from spu_cre-
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ate(2) to address a specific SPU context. When the context gets sched-
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uled to a physical SPU, it starts execution at the instruction pointer
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passed in npc.
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Execution of SPU code happens synchronously, meaning that spu_run does
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not return while the SPU is still running. If there is a need to exe-
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cute SPU code in parallel with other code on either the main CPU or
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other SPUs, you need to create a new thread of execution first, e.g.
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using the pthread_create(3) call.
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When spu_run returns, the current value of the SPU instruction pointer
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is written back to npc, so you can call spu_run again without updating
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the pointers.
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event can be a NULL pointer or point to an extended status code that
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gets filled when spu_run returns. It can be one of the following con-
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stants:
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SPE_EVENT_DMA_ALIGNMENT
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A DMA alignment error
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SPE_EVENT_SPE_DATA_SEGMENT
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A DMA segmentation error
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SPE_EVENT_SPE_DATA_STORAGE
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A DMA storage error
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If NULL is passed as the event argument, these errors will result in a
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signal delivered to the calling process.
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Return Value
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============
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spu_run returns the value of the spu_status register or -1 to indicate
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an error and set errno to one of the error codes listed below. The
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spu_status register value contains a bit mask of status codes and
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optionally a 14 bit code returned from the stop-and-signal instruction
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on the SPU. The bit masks for the status codes are:
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0x02
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SPU was stopped by stop-and-signal.
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0x04
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SPU was stopped by halt.
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0x08
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SPU is waiting for a channel.
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0x10
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SPU is in single-step mode.
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0x20
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SPU has tried to execute an invalid instruction.
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0x40
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SPU has tried to access an invalid channel.
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0x3fff0000
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The bits masked with this value contain the code returned from
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stop-and-signal.
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There are always one or more of the lower eight bits set or an error
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code is returned from spu_run.
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Errors
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======
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EAGAIN or EWOULDBLOCK
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fd is in non-blocking mode and spu_run would block.
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EBADF fd is not a valid file descriptor.
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EFAULT npc is not a valid pointer or status is neither NULL nor a valid
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pointer.
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EINTR A signal occurred while spu_run was in progress. The npc value
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has been updated to the new program counter value if necessary.
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EINVAL fd is not a file descriptor returned from spu_create(2).
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ENOMEM Insufficient memory was available to handle a page fault result-
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ing from an MFC direct memory access.
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ENOSYS the functionality is not provided by the current system, because
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either the hardware does not provide SPUs or the spufs module is
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not loaded.
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Notes
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=====
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spu_run is meant to be used from libraries that implement a more
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abstract interface to SPUs, not to be used from regular applications.
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See http://www.bsc.es/projects/deepcomputing/linuxoncell/ for the rec-
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ommended libraries.
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Conforming to
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=============
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This call is Linux specific and only implemented by the ppc64 architec-
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ture. Programs using this system call are not portable.
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Bugs
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====
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The code does not yet fully implement all features lined out here.
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Author
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======
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Arnd Bergmann <arndb@de.ibm.com>
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See Also
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========
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capabilities(7), close(2), spu_create(2), spufs(7)
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