Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/fault.c b/arch/powerpc/platforms/cell/spufs/fault.c
new file mode 100644
index 0000000000..24adbe3c60
--- /dev/null
+++ b/arch/powerpc/platforms/cell/spufs/fault.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Low-level SPU handling
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * Author: Arnd Bergmann <arndb@de.ibm.com>
+ */
+#include <linux/sched/signal.h>
+#include <linux/mm.h>
+
+#include <asm/spu.h>
+#include <asm/spu_csa.h>
+
+#include "spufs.h"
+
+/**
+ * Handle an SPE event, depending on context SPU_CREATE_EVENTS_ENABLED flag.
+ *
+ * If the context was created with events, we just set the return event.
+ * Otherwise, send an appropriate signal to the process.
+ */
+static void spufs_handle_event(struct spu_context *ctx,
+				unsigned long ea, int type)
+{
+	if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
+		ctx->event_return |= type;
+		wake_up_all(&ctx->stop_wq);
+		return;
+	}
+
+	switch (type) {
+	case SPE_EVENT_INVALID_DMA:
+		force_sig_fault(SIGBUS, BUS_OBJERR, NULL);
+		break;
+	case SPE_EVENT_SPE_DATA_STORAGE:
+		ctx->ops->restart_dma(ctx);
+		force_sig_fault(SIGSEGV, SEGV_ACCERR, (void __user *)ea);
+		break;
+	case SPE_EVENT_DMA_ALIGNMENT:
+		/* DAR isn't set for an alignment fault :( */
+		force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
+		break;
+	case SPE_EVENT_SPE_ERROR:
+		force_sig_fault(
+			SIGILL, ILL_ILLOPC,
+			(void __user *)(unsigned long)
+			ctx->ops->npc_read(ctx) - 4);
+		break;
+	}
+}
+
+int spufs_handle_class0(struct spu_context *ctx)
+{
+	unsigned long stat = ctx->csa.class_0_pending & CLASS0_INTR_MASK;
+
+	if (likely(!stat))
+		return 0;
+
+	if (stat & CLASS0_DMA_ALIGNMENT_INTR)
+		spufs_handle_event(ctx, ctx->csa.class_0_dar,
+			SPE_EVENT_DMA_ALIGNMENT);
+
+	if (stat & CLASS0_INVALID_DMA_COMMAND_INTR)
+		spufs_handle_event(ctx, ctx->csa.class_0_dar,
+			SPE_EVENT_INVALID_DMA);
+
+	if (stat & CLASS0_SPU_ERROR_INTR)
+		spufs_handle_event(ctx, ctx->csa.class_0_dar,
+			SPE_EVENT_SPE_ERROR);
+
+	ctx->csa.class_0_pending = 0;
+
+	return -EIO;
+}
+
+/*
+ * bottom half handler for page faults, we can't do this from
+ * interrupt context, since we might need to sleep.
+ * we also need to give up the mutex so we can get scheduled
+ * out while waiting for the backing store.
+ *
+ * TODO: try calling hash_page from the interrupt handler first
+ *       in order to speed up the easy case.
+ */
+int spufs_handle_class1(struct spu_context *ctx)
+{
+	u64 ea, dsisr, access;
+	unsigned long flags;
+	vm_fault_t flt = 0;
+	int ret;
+
+	/*
+	 * dar and dsisr get passed from the registers
+	 * to the spu_context, to this function, but not
+	 * back to the spu if it gets scheduled again.
+	 *
+	 * if we don't handle the fault for a saved context
+	 * in time, we can still expect to get the same fault
+	 * the immediately after the context restore.
+	 */
+	ea = ctx->csa.class_1_dar;
+	dsisr = ctx->csa.class_1_dsisr;
+
+	if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
+		return 0;
+
+	spuctx_switch_state(ctx, SPU_UTIL_IOWAIT);
+
+	pr_debug("ctx %p: ea %016llx, dsisr %016llx state %d\n", ctx, ea,
+		dsisr, ctx->state);
+
+	ctx->stats.hash_flt++;
+	if (ctx->state == SPU_STATE_RUNNABLE)
+		ctx->spu->stats.hash_flt++;
+
+	/* we must not hold the lock when entering copro_handle_mm_fault */
+	spu_release(ctx);
+
+	access = (_PAGE_PRESENT | _PAGE_READ);
+	access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_WRITE : 0UL;
+	local_irq_save(flags);
+	ret = hash_page(ea, access, 0x300, dsisr);
+	local_irq_restore(flags);
+
+	/* hashing failed, so try the actual fault handler */
+	if (ret)
+		ret = copro_handle_mm_fault(current->mm, ea, dsisr, &flt);
+
+	/*
+	 * 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);
+
+	/*
+	 * Clear dsisr under ctxt lock after handling the fault, so that
+	 * time slicing will not preempt the context while the page fault
+	 * handler is running. Context switch code removes mappings.
+	 */
+	ctx->csa.class_1_dar = ctx->csa.class_1_dsisr = 0;
+
+	/*
+	 * If we handled the fault successfully and are in runnable
+	 * state, restart the DMA.
+	 * In case of unhandled error report the problem to user space.
+	 */
+	if (!ret) {
+		if (flt & VM_FAULT_MAJOR)
+			ctx->stats.maj_flt++;
+		else
+			ctx->stats.min_flt++;
+		if (ctx->state == SPU_STATE_RUNNABLE) {
+			if (flt & VM_FAULT_MAJOR)
+				ctx->spu->stats.maj_flt++;
+			else
+				ctx->spu->stats.min_flt++;
+		}
+
+		if (ctx->spu)
+			ctx->ops->restart_dma(ctx);
+	} else
+		spufs_handle_event(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
+
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+	return ret;
+}