1 files changed, 450 insertions, 0 deletions

diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
new file mode 100644
index 000000000..2e4dcfebf
--- /dev/null
+++ b/drivers/misc/cxl/irq.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2014 IBM Corp.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/pid.h>
+#include <asm/cputable.h>
+#include <misc/cxl-base.h>
+
+#include "cxl.h"
+#include "trace.h"
+
+static int afu_irq_range_start(void)
+{
+	if (cpu_has_feature(CPU_FTR_HVMODE))
+		return 1;
+	return 0;
+}
+
+static irqreturn_t schedule_cxl_fault(struct cxl_context *ctx, u64 dsisr, u64 dar)
+{
+	ctx->dsisr = dsisr;
+	ctx->dar = dar;
+	schedule_work(&ctx->fault_work);
+	return IRQ_HANDLED;
+}
+
+irqreturn_t cxl_irq_psl9(int irq, struct cxl_context *ctx, struct cxl_irq_info *irq_info)
+{
+	u64 dsisr, dar;
+
+	dsisr = irq_info->dsisr;
+	dar = irq_info->dar;
+
+	trace_cxl_psl9_irq(ctx, irq, dsisr, dar);
+
+	pr_devel("CXL interrupt %i for afu pe: %i DSISR: %#llx DAR: %#llx\n", irq, ctx->pe, dsisr, dar);
+
+	if (dsisr & CXL_PSL9_DSISR_An_TF) {
+		pr_devel("CXL interrupt: Scheduling translation fault handling for later (pe: %i)\n", ctx->pe);
+		return schedule_cxl_fault(ctx, dsisr, dar);
+	}
+
+	if (dsisr & CXL_PSL9_DSISR_An_PE)
+		return cxl_ops->handle_psl_slice_error(ctx, dsisr,
+						irq_info->errstat);
+	if (dsisr & CXL_PSL9_DSISR_An_AE) {
+		pr_devel("CXL interrupt: AFU Error 0x%016llx\n", irq_info->afu_err);
+
+		if (ctx->pending_afu_err) {
+			/*
+			 * This shouldn't happen - the PSL treats these errors
+			 * as fatal and will have reset the AFU, so there's not
+			 * much point buffering multiple AFU errors.
+			 * OTOH if we DO ever see a storm of these come in it's
+			 * probably best that we log them somewhere:
+			 */
+			dev_err_ratelimited(&ctx->afu->dev, "CXL AFU Error undelivered to pe %i: 0x%016llx\n",
+					    ctx->pe, irq_info->afu_err);
+		} else {
+			spin_lock(&ctx->lock);
+			ctx->afu_err = irq_info->afu_err;
+			ctx->pending_afu_err = 1;
+			spin_unlock(&ctx->lock);
+
+			wake_up_all(&ctx->wq);
+		}
+
+		cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_A, 0);
+		return IRQ_HANDLED;
+	}
+	if (dsisr & CXL_PSL9_DSISR_An_OC)
+		pr_devel("CXL interrupt: OS Context Warning\n");
+
+	WARN(1, "Unhandled CXL PSL IRQ\n");
+	return IRQ_HANDLED;
+}
+
+irqreturn_t cxl_irq_psl8(int irq, struct cxl_context *ctx, struct cxl_irq_info *irq_info)
+{
+	u64 dsisr, dar;
+
+	dsisr = irq_info->dsisr;
+	dar = irq_info->dar;
+
+	trace_cxl_psl_irq(ctx, irq, dsisr, dar);
+
+	pr_devel("CXL interrupt %i for afu pe: %i DSISR: %#llx DAR: %#llx\n", irq, ctx->pe, dsisr, dar);
+
+	if (dsisr & CXL_PSL_DSISR_An_DS) {
+		/*
+		 * We don't inherently need to sleep to handle this, but we do
+		 * need to get a ref to the task's mm, which we can't do from
+		 * irq context without the potential for a deadlock since it
+		 * takes the task_lock. An alternate option would be to keep a
+		 * reference to the task's mm the entire time it has cxl open,
+		 * but to do that we need to solve the issue where we hold a
+		 * ref to the mm, but the mm can hold a ref to the fd after an
+		 * mmap preventing anything from being cleaned up.
+		 */
+		pr_devel("Scheduling segment miss handling for later pe: %i\n", ctx->pe);
+		return schedule_cxl_fault(ctx, dsisr, dar);
+	}
+
+	if (dsisr & CXL_PSL_DSISR_An_M)
+		pr_devel("CXL interrupt: PTE not found\n");
+	if (dsisr & CXL_PSL_DSISR_An_P)
+		pr_devel("CXL interrupt: Storage protection violation\n");
+	if (dsisr & CXL_PSL_DSISR_An_A)
+		pr_devel("CXL interrupt: AFU lock access to write through or cache inhibited storage\n");
+	if (dsisr & CXL_PSL_DSISR_An_S)
+		pr_devel("CXL interrupt: Access was afu_wr or afu_zero\n");
+	if (dsisr & CXL_PSL_DSISR_An_K)
+		pr_devel("CXL interrupt: Access not permitted by virtual page class key protection\n");
+
+	if (dsisr & CXL_PSL_DSISR_An_DM) {
+		/*
+		 * In some cases we might be able to handle the fault
+		 * immediately if hash_page would succeed, but we still need
+		 * the task's mm, which as above we can't get without a lock
+		 */
+		pr_devel("Scheduling page fault handling for later pe: %i\n", ctx->pe);
+		return schedule_cxl_fault(ctx, dsisr, dar);
+	}
+	if (dsisr & CXL_PSL_DSISR_An_ST)
+		WARN(1, "CXL interrupt: Segment Table PTE not found\n");
+	if (dsisr & CXL_PSL_DSISR_An_UR)
+		pr_devel("CXL interrupt: AURP PTE not found\n");
+	if (dsisr & CXL_PSL_DSISR_An_PE)
+		return cxl_ops->handle_psl_slice_error(ctx, dsisr,
+						irq_info->errstat);
+	if (dsisr & CXL_PSL_DSISR_An_AE) {
+		pr_devel("CXL interrupt: AFU Error 0x%016llx\n", irq_info->afu_err);
+
+		if (ctx->pending_afu_err) {
+			/*
+			 * This shouldn't happen - the PSL treats these errors
+			 * as fatal and will have reset the AFU, so there's not
+			 * much point buffering multiple AFU errors.
+			 * OTOH if we DO ever see a storm of these come in it's
+			 * probably best that we log them somewhere:
+			 */
+			dev_err_ratelimited(&ctx->afu->dev, "CXL AFU Error "
+					    "undelivered to pe %i: 0x%016llx\n",
+					    ctx->pe, irq_info->afu_err);
+		} else {
+			spin_lock(&ctx->lock);
+			ctx->afu_err = irq_info->afu_err;
+			ctx->pending_afu_err = true;
+			spin_unlock(&ctx->lock);
+
+			wake_up_all(&ctx->wq);
+		}
+
+		cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_A, 0);
+		return IRQ_HANDLED;
+	}
+	if (dsisr & CXL_PSL_DSISR_An_OC)
+		pr_devel("CXL interrupt: OS Context Warning\n");
+
+	WARN(1, "Unhandled CXL PSL IRQ\n");
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t cxl_irq_afu(int irq, void *data)
+{
+	struct cxl_context *ctx = data;
+	irq_hw_number_t hwirq = irqd_to_hwirq(irq_get_irq_data(irq));
+	int irq_off, afu_irq = 0;
+	__u16 range;
+	int r;
+
+	/*
+	 * Look for the interrupt number.
+	 * On bare-metal, we know range 0 only contains the PSL
+	 * interrupt so we could start counting at range 1 and initialize
+	 * afu_irq at 1.
+	 * In a guest, range 0 also contains AFU interrupts, so it must
+	 * be counted for. Therefore we initialize afu_irq at 0 to take into
+	 * account the PSL interrupt.
+	 *
+	 * For code-readability, it just seems easier to go over all
+	 * the ranges on bare-metal and guest. The end result is the same.
+	 */
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		irq_off = hwirq - ctx->irqs.offset[r];
+		range = ctx->irqs.range[r];
+		if (irq_off >= 0 && irq_off < range) {
+			afu_irq += irq_off;
+			break;
+		}
+		afu_irq += range;
+	}
+	if (unlikely(r >= CXL_IRQ_RANGES)) {
+		WARN(1, "Received AFU IRQ out of range for pe %i (virq %i hwirq %lx)\n",
+		     ctx->pe, irq, hwirq);
+		return IRQ_HANDLED;
+	}
+
+	trace_cxl_afu_irq(ctx, afu_irq, irq, hwirq);
+	pr_devel("Received AFU interrupt %i for pe: %i (virq %i hwirq %lx)\n",
+	       afu_irq, ctx->pe, irq, hwirq);
+
+	if (unlikely(!ctx->irq_bitmap)) {
+		WARN(1, "Received AFU IRQ for context with no IRQ bitmap\n");
+		return IRQ_HANDLED;
+	}
+	spin_lock(&ctx->lock);
+	set_bit(afu_irq - 1, ctx->irq_bitmap);
+	ctx->pending_irq = true;
+	spin_unlock(&ctx->lock);
+
+	wake_up_all(&ctx->wq);
+
+	return IRQ_HANDLED;
+}
+
+unsigned int cxl_map_irq(struct cxl *adapter, irq_hw_number_t hwirq,
+			 irq_handler_t handler, void *cookie, const char *name)
+{
+	unsigned int virq;
+	int result;
+
+	/* IRQ Domain? */
+	virq = irq_create_mapping(NULL, hwirq);
+	if (!virq) {
+		dev_warn(&adapter->dev, "cxl_map_irq: irq_create_mapping failed\n");
+		return 0;
+	}
+
+	if (cxl_ops->setup_irq)
+		cxl_ops->setup_irq(adapter, hwirq, virq);
+
+	pr_devel("hwirq %#lx mapped to virq %u\n", hwirq, virq);
+
+	result = request_irq(virq, handler, 0, name, cookie);
+	if (result) {
+		dev_warn(&adapter->dev, "cxl_map_irq: request_irq failed: %i\n", result);
+		return 0;
+	}
+
+	return virq;
+}
+
+void cxl_unmap_irq(unsigned int virq, void *cookie)
+{
+	free_irq(virq, cookie);
+}
+
+int cxl_register_one_irq(struct cxl *adapter,
+			irq_handler_t handler,
+			void *cookie,
+			irq_hw_number_t *dest_hwirq,
+			unsigned int *dest_virq,
+			const char *name)
+{
+	int hwirq, virq;
+
+	if ((hwirq = cxl_ops->alloc_one_irq(adapter)) < 0)
+		return hwirq;
+
+	if (!(virq = cxl_map_irq(adapter, hwirq, handler, cookie, name)))
+		goto err;
+
+	*dest_hwirq = hwirq;
+	*dest_virq = virq;
+
+	return 0;
+
+err:
+	cxl_ops->release_one_irq(adapter, hwirq);
+	return -ENOMEM;
+}
+
+void afu_irq_name_free(struct cxl_context *ctx)
+{
+	struct cxl_irq_name *irq_name, *tmp;
+
+	list_for_each_entry_safe(irq_name, tmp, &ctx->irq_names, list) {
+		kfree(irq_name->name);
+		list_del(&irq_name->list);
+		kfree(irq_name);
+	}
+}
+
+int afu_allocate_irqs(struct cxl_context *ctx, u32 count)
+{
+	int rc, r, i, j = 1;
+	struct cxl_irq_name *irq_name;
+	int alloc_count;
+
+	/*
+	 * In native mode, range 0 is reserved for the multiplexed
+	 * PSL interrupt. It has been allocated when the AFU was initialized.
+	 *
+	 * In a guest, the PSL interrupt is not mutliplexed, but per-context,
+	 * and is the first interrupt from range 0. It still needs to be
+	 * allocated, so bump the count by one.
+	 */
+	if (cpu_has_feature(CPU_FTR_HVMODE))
+		alloc_count = count;
+	else
+		alloc_count = count + 1;
+
+	if ((rc = cxl_ops->alloc_irq_ranges(&ctx->irqs, ctx->afu->adapter,
+							alloc_count)))
+		return rc;
+
+	if (cpu_has_feature(CPU_FTR_HVMODE)) {
+		/* Multiplexed PSL Interrupt */
+		ctx->irqs.offset[0] = ctx->afu->native->psl_hwirq;
+		ctx->irqs.range[0] = 1;
+	}
+
+	ctx->irq_count = count;
+	ctx->irq_bitmap = kcalloc(BITS_TO_LONGS(count),
+				  sizeof(*ctx->irq_bitmap), GFP_KERNEL);
+	if (!ctx->irq_bitmap)
+		goto out;
+
+	/*
+	 * Allocate names first.  If any fail, bail out before allocating
+	 * actual hardware IRQs.
+	 */
+	for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) {
+		for (i = 0; i < ctx->irqs.range[r]; i++) {
+			irq_name = kmalloc(sizeof(struct cxl_irq_name),
+					   GFP_KERNEL);
+			if (!irq_name)
+				goto out;
+			irq_name->name = kasprintf(GFP_KERNEL, "cxl-%s-pe%i-%i",
+						   dev_name(&ctx->afu->dev),
+						   ctx->pe, j);
+			if (!irq_name->name) {
+				kfree(irq_name);
+				goto out;
+			}
+			/* Add to tail so next look get the correct order */
+			list_add_tail(&irq_name->list, &ctx->irq_names);
+			j++;
+		}
+	}
+	return 0;
+
+out:
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+	bitmap_free(ctx->irq_bitmap);
+	afu_irq_name_free(ctx);
+	return -ENOMEM;
+}
+
+static void afu_register_hwirqs(struct cxl_context *ctx)
+{
+	irq_hw_number_t hwirq;
+	struct cxl_irq_name *irq_name;
+	int r, i;
+	irqreturn_t (*handler)(int irq, void *data);
+
+	/* We've allocated all memory now, so let's do the irq allocations */
+	irq_name = list_first_entry(&ctx->irq_names, struct cxl_irq_name, list);
+	for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) {
+		hwirq = ctx->irqs.offset[r];
+		for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
+			if (r == 0 && i == 0)
+				/*
+				 * The very first interrupt of range 0 is
+				 * always the PSL interrupt, but we only
+				 * need to connect a handler for guests,
+				 * because there's one PSL interrupt per
+				 * context.
+				 * On bare-metal, the PSL interrupt is
+				 * multiplexed and was setup when the AFU
+				 * was configured.
+				 */
+				handler = cxl_ops->psl_interrupt;
+			else
+				handler = cxl_irq_afu;
+			cxl_map_irq(ctx->afu->adapter, hwirq, handler, ctx,
+				irq_name->name);
+			irq_name = list_next_entry(irq_name, list);
+		}
+	}
+}
+
+int afu_register_irqs(struct cxl_context *ctx, u32 count)
+{
+	int rc;
+
+	rc = afu_allocate_irqs(ctx, count);
+	if (rc)
+		return rc;
+
+	afu_register_hwirqs(ctx);
+	return 0;
+}
+
+void afu_release_irqs(struct cxl_context *ctx, void *cookie)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+	int r, i;
+
+	for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) {
+		hwirq = ctx->irqs.offset[r];
+		for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
+			virq = irq_find_mapping(NULL, hwirq);
+			if (virq)
+				cxl_unmap_irq(virq, cookie);
+		}
+	}
+
+	afu_irq_name_free(ctx);
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+
+	ctx->irq_count = 0;
+}
+
+void cxl_afu_decode_psl_serr(struct cxl_afu *afu, u64 serr)
+{
+	dev_crit(&afu->dev,
+		 "PSL Slice error received. Check AFU for root cause.\n");
+	dev_crit(&afu->dev, "PSL_SERR_An: 0x%016llx\n", serr);
+	if (serr & CXL_PSL_SERR_An_afuto)
+		dev_crit(&afu->dev, "AFU MMIO Timeout\n");
+	if (serr & CXL_PSL_SERR_An_afudis)
+		dev_crit(&afu->dev,
+			 "MMIO targeted Accelerator that was not enabled\n");
+	if (serr & CXL_PSL_SERR_An_afuov)
+		dev_crit(&afu->dev, "AFU CTAG Overflow\n");
+	if (serr & CXL_PSL_SERR_An_badsrc)
+		dev_crit(&afu->dev, "Bad Interrupt Source\n");
+	if (serr & CXL_PSL_SERR_An_badctx)
+		dev_crit(&afu->dev, "Bad Context Handle\n");
+	if (serr & CXL_PSL_SERR_An_llcmdis)
+		dev_crit(&afu->dev, "LLCMD to Disabled AFU\n");
+	if (serr & CXL_PSL_SERR_An_llcmdto)
+		dev_crit(&afu->dev, "LLCMD Timeout to AFU\n");
+	if (serr & CXL_PSL_SERR_An_afupar)
+		dev_crit(&afu->dev, "AFU MMIO Parity Error\n");
+	if (serr & CXL_PSL_SERR_An_afudup)
+		dev_crit(&afu->dev, "AFU MMIO Duplicate CTAG Error\n");
+	if (serr & CXL_PSL_SERR_An_AE)
+		dev_crit(&afu->dev,
+			 "AFU asserted JDONE with JERROR in AFU Directed Mode\n");
+}