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path: root/arch/powerpc/platforms/cell/spufs/run.c
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Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/run.c')
-rw-r--r--arch/powerpc/platforms/cell/spufs/run.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index 18ea8866c61..c04e078c0fe 100644
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -76,6 +76,90 @@ static inline int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc,
return 0;
}
+/*
+ * SPU syscall restarting is tricky because we violate the basic
+ * assumption that the signal handler is running on the interrupted
+ * thread. Here instead, the handler runs on PowerPC user space code,
+ * while the syscall was called from the SPU.
+ * This means we can only do a very rough approximation of POSIX
+ * signal semantics.
+ */
+int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
+ unsigned int *npc)
+{
+ int ret;
+
+ switch (*spu_ret) {
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ /*
+ * Enter the regular syscall restarting for
+ * sys_spu_run, then restart the SPU syscall
+ * callback.
+ */
+ *npc -= 8;
+ ret = -ERESTARTSYS;
+ break;
+ case -ERESTARTNOHAND:
+ case -ERESTART_RESTARTBLOCK:
+ /*
+ * Restart block is too hard for now, just return -EINTR
+ * to the SPU.
+ * ERESTARTNOHAND comes from sys_pause, we also return
+ * -EINTR from there.
+ * Assume that we need to be restarted ourselves though.
+ */
+ *spu_ret = -EINTR;
+ ret = -ERESTARTSYS;
+ break;
+ default:
+ printk(KERN_WARNING "%s: unexpected return code %ld\n",
+ __FUNCTION__, *spu_ret);
+ ret = 0;
+ }
+ return ret;
+}
+
+int spu_process_callback(struct spu_context *ctx)
+{
+ struct spu_syscall_block s;
+ u32 ls_pointer, npc;
+ char *ls;
+ long spu_ret;
+ int ret;
+
+ /* get syscall block from local store */
+ npc = ctx->ops->npc_read(ctx);
+ ls = ctx->ops->get_ls(ctx);
+ ls_pointer = *(u32*)(ls + npc);
+ if (ls_pointer > (LS_SIZE - sizeof(s)))
+ return -EFAULT;
+ memcpy(&s, ls + ls_pointer, sizeof (s));
+
+ /* do actual syscall without pinning the spu */
+ ret = 0;
+ spu_ret = -ENOSYS;
+ npc += 4;
+
+ if (s.nr_ret < __NR_syscalls) {
+ spu_release(ctx);
+ /* do actual system call from here */
+ spu_ret = spu_sys_callback(&s);
+ if (spu_ret <= -ERESTARTSYS) {
+ ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
+ }
+ spu_acquire(ctx);
+ if (ret == -ERESTARTSYS)
+ return ret;
+ }
+
+ /* write result, jump over indirect pointer */
+ memcpy(ls + ls_pointer, &spu_ret, sizeof (spu_ret));
+ ctx->ops->npc_write(ctx, npc);
+ ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
+ return ret;
+}
+
static inline int spu_process_events(struct spu_context *ctx)
{
struct spu *spu = ctx->spu;
@@ -107,6 +191,13 @@ long spufs_run_spu(struct file *file, struct spu_context *ctx,
ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, status));
if (unlikely(ret))
break;
+ if ((*status & SPU_STATUS_STOPPED_BY_STOP) &&
+ (*status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
+ ret = spu_process_callback(ctx);
+ if (ret)
+ break;
+ *status &= ~SPU_STATUS_STOPPED_BY_STOP;
+ }
if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
ret = spu_reacquire_runnable(ctx, npc, status);
if (ret)