1 files changed, 451 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
new file mode 100644
index 000000000..ce52b8749
--- /dev/null
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0
+#define DEBUG
+
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+
+#include <asm/spu.h>
+#include <asm/spu_priv1.h>
+#include <asm/io.h>
+#include <asm/unistd.h>
+
+#include "spufs.h"
+
+/* interrupt-level stop callback function. */
+void spufs_stop_callback(struct spu *spu, int irq)
+{
+	struct spu_context *ctx = spu->ctx;
+
+	/*
+	 * It should be impossible to preempt a context while an exception
+	 * is being processed, since the context switch code is specially
+	 * coded to deal with interrupts ... But, just in case, sanity check
+	 * the context pointer.  It is OK to return doing nothing since
+	 * the exception will be regenerated when the context is resumed.
+	 */
+	if (ctx) {
+		/* Copy exception arguments into module specific structure */
+		switch(irq) {
+		case 0 :
+			ctx->csa.class_0_pending = spu->class_0_pending;
+			ctx->csa.class_0_dar = spu->class_0_dar;
+			break;
+		case 1 :
+			ctx->csa.class_1_dsisr = spu->class_1_dsisr;
+			ctx->csa.class_1_dar = spu->class_1_dar;
+			break;
+		case 2 :
+			break;
+		}
+
+		/* ensure that the exception status has hit memory before a
+		 * thread waiting on the context's stop queue is woken */
+		smp_wmb();
+
+		wake_up_all(&ctx->stop_wq);
+	}
+}
+
+int spu_stopped(struct spu_context *ctx, u32 *stat)
+{
+	u64 dsisr;
+	u32 stopped;
+
+	stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
+		SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
+
+top:
+	*stat = ctx->ops->status_read(ctx);
+	if (*stat & stopped) {
+		/*
+		 * If the spu hasn't finished stopping, we need to
+		 * re-read the register to get the stopped value.
+		 */
+		if (*stat & SPU_STATUS_RUNNING)
+			goto top;
+		return 1;
+	}
+
+	if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
+		return 1;
+
+	dsisr = ctx->csa.class_1_dsisr;
+	if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
+		return 1;
+
+	if (ctx->csa.class_0_pending)
+		return 1;
+
+	return 0;
+}
+
+static int spu_setup_isolated(struct spu_context *ctx)
+{
+	int ret;
+	u64 __iomem *mfc_cntl;
+	u64 sr1;
+	u32 status;
+	unsigned long timeout;
+	const u32 status_loading = SPU_STATUS_RUNNING
+		| SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
+
+	ret = -ENODEV;
+	if (!isolated_loader)
+		goto out;
+
+	/*
+	 * We need to exclude userspace access to the context.
+	 *
+	 * To protect against memory access we invalidate all ptes
+	 * and make sure the pagefault handlers block on the mutex.
+	 */
+	spu_unmap_mappings(ctx);
+
+	mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
+
+	/* purge the MFC DMA queue to ensure no spurious accesses before we
+	 * enter kernel mode */
+	timeout = jiffies + HZ;
+	out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
+	while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
+			!= MFC_CNTL_PURGE_DMA_COMPLETE) {
+		if (time_after(jiffies, timeout)) {
+			printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
+					__func__);
+			ret = -EIO;
+			goto out;
+		}
+		cond_resched();
+	}
+
+	/* clear purge status */
+	out_be64(mfc_cntl, 0);
+
+	/* put the SPE in kernel mode to allow access to the loader */
+	sr1 = spu_mfc_sr1_get(ctx->spu);
+	sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
+	spu_mfc_sr1_set(ctx->spu, sr1);
+
+	/* start the loader */
+	ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
+	ctx->ops->signal2_write(ctx,
+			(unsigned long)isolated_loader & 0xffffffff);
+
+	ctx->ops->runcntl_write(ctx,
+			SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
+
+	ret = 0;
+	timeout = jiffies + HZ;
+	while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
+				status_loading) {
+		if (time_after(jiffies, timeout)) {
+			printk(KERN_ERR "%s: timeout waiting for loader\n",
+					__func__);
+			ret = -EIO;
+			goto out_drop_priv;
+		}
+		cond_resched();
+	}
+
+	if (!(status & SPU_STATUS_RUNNING)) {
+		/* If isolated LOAD has failed: run SPU, we will get a stop-and
+		 * signal later. */
+		pr_debug("%s: isolated LOAD failed\n", __func__);
+		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
+		ret = -EACCES;
+		goto out_drop_priv;
+	}
+
+	if (!(status & SPU_STATUS_ISOLATED_STATE)) {
+		/* This isn't allowed by the CBEA, but check anyway */
+		pr_debug("%s: SPU fell out of isolated mode?\n", __func__);
+		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
+		ret = -EINVAL;
+		goto out_drop_priv;
+	}
+
+out_drop_priv:
+	/* Finished accessing the loader. Drop kernel mode */
+	sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
+	spu_mfc_sr1_set(ctx->spu, sr1);
+
+out:
+	return ret;
+}
+
+static int spu_run_init(struct spu_context *ctx, u32 *npc)
+{
+	unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
+	int ret;
+
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
+	/*
+	 * NOSCHED is synchronous scheduling with respect to the caller.
+	 * The caller waits for the context to be loaded.
+	 */
+	if (ctx->flags & SPU_CREATE_NOSCHED) {
+		if (ctx->state == SPU_STATE_SAVED) {
+			ret = spu_activate(ctx, 0);
+			if (ret)
+				return ret;
+		}
+	}
+
+	/*
+	 * Apply special setup as required.
+	 */
+	if (ctx->flags & SPU_CREATE_ISOLATE) {
+		if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
+			ret = spu_setup_isolated(ctx);
+			if (ret)
+				return ret;
+		}
+
+		/*
+		 * If userspace has set the runcntrl register (eg, to
+		 * issue an isolated exit), we need to re-set it here
+		 */
+		runcntl = ctx->ops->runcntl_read(ctx) &
+			(SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
+		if (runcntl == 0)
+			runcntl = SPU_RUNCNTL_RUNNABLE;
+	} else {
+		unsigned long privcntl;
+
+		if (test_thread_flag(TIF_SINGLESTEP))
+			privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
+		else
+			privcntl = SPU_PRIVCNTL_MODE_NORMAL;
+
+		ctx->ops->privcntl_write(ctx, privcntl);
+		ctx->ops->npc_write(ctx, *npc);
+	}
+
+	ctx->ops->runcntl_write(ctx, runcntl);
+
+	if (ctx->flags & SPU_CREATE_NOSCHED) {
+		spuctx_switch_state(ctx, SPU_UTIL_USER);
+	} else {
+
+		if (ctx->state == SPU_STATE_SAVED) {
+			ret = spu_activate(ctx, 0);
+			if (ret)
+				return ret;
+		} else {
+			spuctx_switch_state(ctx, SPU_UTIL_USER);
+		}
+	}
+
+	set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
+	return 0;
+}
+
+static int spu_run_fini(struct spu_context *ctx, u32 *npc,
+			       u32 *status)
+{
+	int ret = 0;
+
+	spu_del_from_rq(ctx);
+
+	*status = ctx->ops->status_read(ctx);
+	*npc = ctx->ops->npc_read(ctx);
+
+	spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
+	clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
+	spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, *status);
+	spu_release(ctx);
+
+	if (signal_pending(current))
+		ret = -ERESTARTSYS;
+
+	return ret;
+}
+
+/*
+ * 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.
+ */
+static 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",
+			__func__, *spu_ret);
+		ret = 0;
+	}
+	return ret;
+}
+
+static int spu_process_callback(struct spu_context *ctx)
+{
+	struct spu_syscall_block s;
+	u32 ls_pointer, npc;
+	void __iomem *ls;
+	long spu_ret;
+	int ret;
+
+	/* get syscall block from local store */
+	npc = ctx->ops->npc_read(ctx) & ~3;
+	ls = (void __iomem *)ctx->ops->get_ls(ctx);
+	ls_pointer = in_be32(ls + npc);
+	if (ls_pointer > (LS_SIZE - sizeof(s)))
+		return -EFAULT;
+	memcpy_fromio(&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);
+		}
+		mutex_lock(&ctx->state_mutex);
+		if (ret == -ERESTARTSYS)
+			return ret;
+	}
+
+	/* need to re-get the ls, as it may have changed when we released the
+	 * spu */
+	ls = (void __iomem *)ctx->ops->get_ls(ctx);
+
+	/* write result, jump over indirect pointer */
+	memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
+	ctx->ops->npc_write(ctx, npc);
+	ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
+	return ret;
+}
+
+long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
+{
+	int ret;
+	u32 status;
+
+	if (mutex_lock_interruptible(&ctx->run_mutex))
+		return -ERESTARTSYS;
+
+	ctx->event_return = 0;
+
+	ret = spu_acquire(ctx);
+	if (ret)
+		goto out_unlock;
+
+	spu_enable_spu(ctx);
+
+	spu_update_sched_info(ctx);
+
+	ret = spu_run_init(ctx, npc);
+	if (ret) {
+		spu_release(ctx);
+		goto out;
+	}
+
+	do {
+		ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
+		if (unlikely(ret)) {
+			/*
+			 * This is nasty: we need the state_mutex for all the
+			 * bookkeeping even if the syscall was interrupted by
+			 * a signal. ewww.
+			 */
+			mutex_lock(&ctx->state_mutex);
+			break;
+		}
+		if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
+						&ctx->sched_flags))) {
+			if (!(status & SPU_STATUS_STOPPED_BY_STOP))
+				continue;
+		}
+
+		spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
+		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;
+		}
+		ret = spufs_handle_class1(ctx);
+		if (ret)
+			break;
+
+		ret = spufs_handle_class0(ctx);
+		if (ret)
+			break;
+
+		if (signal_pending(current))
+			ret = -ERESTARTSYS;
+	} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
+				      SPU_STATUS_STOPPED_BY_HALT |
+				       SPU_STATUS_SINGLE_STEP)));
+
+	spu_disable_spu(ctx);
+	ret = spu_run_fini(ctx, npc, &status);
+	spu_yield(ctx);
+
+	if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
+	    (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
+		ctx->stats.libassist++;
+
+	if ((ret == 0) ||
+	    ((ret == -ERESTARTSYS) &&
+	     ((status & SPU_STATUS_STOPPED_BY_HALT) ||
+	      (status & SPU_STATUS_SINGLE_STEP) ||
+	      ((status & SPU_STATUS_STOPPED_BY_STOP) &&
+	       (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
+		ret = status;
+
+	/* Note: we don't need to force_sig SIGTRAP on single-step
+	 * since we have TIF_SINGLESTEP set, thus the kernel will do
+	 * it upon return from the syscall anyway.
+	 */
+	if (unlikely(status & SPU_STATUS_SINGLE_STEP))
+		ret = -ERESTARTSYS;
+
+	else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
+	    && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
+		force_sig(SIGTRAP);
+		ret = -ERESTARTSYS;
+	}
+
+out:
+	*event = ctx->event_return;
+out_unlock:
+	mutex_unlock(&ctx->run_mutex);
+	return ret;
+}