Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 779 insertions, 0 deletions

diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
new file mode 100644
index 000000000..7749dcd16
--- /dev/null
+++ b/drivers/misc/ocxl/link.c
@@ -0,0 +1,779 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2017 IBM Corp.
+#include <linux/sched/mm.h>
+#include <linux/mutex.h>
+#include <linux/mm.h>
+#include <linux/mm_types.h>
+#include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
+#include <linux/irqdomain.h>
+#include <asm/copro.h>
+#include <asm/pnv-ocxl.h>
+#include <asm/xive.h>
+#include <misc/ocxl.h>
+#include "ocxl_internal.h"
+#include "trace.h"
+
+
+#define SPA_PASID_BITS		15
+#define SPA_PASID_MAX		((1 << SPA_PASID_BITS) - 1)
+#define SPA_PE_MASK		SPA_PASID_MAX
+#define SPA_SPA_SIZE_LOG	22 /* Each SPA is 4 Mb */
+
+#define SPA_CFG_SF		(1ull << (63-0))
+#define SPA_CFG_TA		(1ull << (63-1))
+#define SPA_CFG_HV		(1ull << (63-3))
+#define SPA_CFG_UV		(1ull << (63-4))
+#define SPA_CFG_XLAT_hpt	(0ull << (63-6)) /* Hashed page table (HPT) mode */
+#define SPA_CFG_XLAT_roh	(2ull << (63-6)) /* Radix on HPT mode */
+#define SPA_CFG_XLAT_ror	(3ull << (63-6)) /* Radix on Radix mode */
+#define SPA_CFG_PR		(1ull << (63-49))
+#define SPA_CFG_TC		(1ull << (63-54))
+#define SPA_CFG_DR		(1ull << (63-59))
+
+#define SPA_XSL_TF		(1ull << (63-3))  /* Translation fault */
+#define SPA_XSL_S		(1ull << (63-38)) /* Store operation */
+
+#define SPA_PE_VALID		0x80000000
+
+struct ocxl_link;
+
+struct pe_data {
+	struct mm_struct *mm;
+	/* callback to trigger when a translation fault occurs */
+	void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr);
+	/* opaque pointer to be passed to the above callback */
+	void *xsl_err_data;
+	struct rcu_head rcu;
+	struct ocxl_link *link;
+	struct mmu_notifier mmu_notifier;
+};
+
+struct spa {
+	struct ocxl_process_element *spa_mem;
+	int spa_order;
+	struct mutex spa_lock;
+	struct radix_tree_root pe_tree; /* Maps PE handles to pe_data */
+	char *irq_name;
+	int virq;
+	void __iomem *reg_dsisr;
+	void __iomem *reg_dar;
+	void __iomem *reg_tfc;
+	void __iomem *reg_pe_handle;
+	/*
+	 * The following field are used by the memory fault
+	 * interrupt handler. We can only have one interrupt at a
+	 * time. The NPU won't raise another interrupt until the
+	 * previous one has been ack'd by writing to the TFC register
+	 */
+	struct xsl_fault {
+		struct work_struct fault_work;
+		u64 pe;
+		u64 dsisr;
+		u64 dar;
+		struct pe_data pe_data;
+	} xsl_fault;
+};
+
+/*
+ * A opencapi link can be used be by several PCI functions. We have
+ * one link per device slot.
+ *
+ * A linked list of opencapi links should suffice, as there's a
+ * limited number of opencapi slots on a system and lookup is only
+ * done when the device is probed
+ */
+struct ocxl_link {
+	struct list_head list;
+	struct kref ref;
+	int domain;
+	int bus;
+	int dev;
+	void __iomem *arva;     /* ATSD register virtual address */
+	spinlock_t atsd_lock;   /* to serialize shootdowns */
+	atomic_t irq_available;
+	struct spa *spa;
+	void *platform_data;
+};
+static LIST_HEAD(links_list);
+static DEFINE_MUTEX(links_list_lock);
+
+enum xsl_response {
+	CONTINUE,
+	ADDRESS_ERROR,
+	RESTART,
+};
+
+
+static void read_irq(struct spa *spa, u64 *dsisr, u64 *dar, u64 *pe)
+{
+	u64 reg;
+
+	*dsisr = in_be64(spa->reg_dsisr);
+	*dar = in_be64(spa->reg_dar);
+	reg = in_be64(spa->reg_pe_handle);
+	*pe = reg & SPA_PE_MASK;
+}
+
+static void ack_irq(struct spa *spa, enum xsl_response r)
+{
+	u64 reg = 0;
+
+	/* continue is not supported */
+	if (r == RESTART)
+		reg = PPC_BIT(31);
+	else if (r == ADDRESS_ERROR)
+		reg = PPC_BIT(30);
+	else
+		WARN(1, "Invalid irq response %d\n", r);
+
+	if (reg) {
+		trace_ocxl_fault_ack(spa->spa_mem, spa->xsl_fault.pe,
+				spa->xsl_fault.dsisr, spa->xsl_fault.dar, reg);
+		out_be64(spa->reg_tfc, reg);
+	}
+}
+
+static void xsl_fault_handler_bh(struct work_struct *fault_work)
+{
+	vm_fault_t flt = 0;
+	unsigned long access, flags, inv_flags = 0;
+	enum xsl_response r;
+	struct xsl_fault *fault = container_of(fault_work, struct xsl_fault,
+					fault_work);
+	struct spa *spa = container_of(fault, struct spa, xsl_fault);
+
+	int rc;
+
+	/*
+	 * We must release a reference on mm_users whenever exiting this
+	 * function (taken in the memory fault interrupt handler)
+	 */
+	rc = copro_handle_mm_fault(fault->pe_data.mm, fault->dar, fault->dsisr,
+				&flt);
+	if (rc) {
+		pr_debug("copro_handle_mm_fault failed: %d\n", rc);
+		if (fault->pe_data.xsl_err_cb) {
+			fault->pe_data.xsl_err_cb(
+				fault->pe_data.xsl_err_data,
+				fault->dar, fault->dsisr);
+		}
+		r = ADDRESS_ERROR;
+		goto ack;
+	}
+
+	if (!radix_enabled()) {
+		/*
+		 * update_mmu_cache() will not have loaded the hash
+		 * since current->trap is not a 0x400 or 0x300, so
+		 * just call hash_page_mm() here.
+		 */
+		access = _PAGE_PRESENT | _PAGE_READ;
+		if (fault->dsisr & SPA_XSL_S)
+			access |= _PAGE_WRITE;
+
+		if (get_region_id(fault->dar) != USER_REGION_ID)
+			access |= _PAGE_PRIVILEGED;
+
+		local_irq_save(flags);
+		hash_page_mm(fault->pe_data.mm, fault->dar, access, 0x300,
+			inv_flags);
+		local_irq_restore(flags);
+	}
+	r = RESTART;
+ack:
+	mmput(fault->pe_data.mm);
+	ack_irq(spa, r);
+}
+
+static irqreturn_t xsl_fault_handler(int irq, void *data)
+{
+	struct ocxl_link *link = data;
+	struct spa *spa = link->spa;
+	u64 dsisr, dar, pe_handle;
+	struct pe_data *pe_data;
+	struct ocxl_process_element *pe;
+	int pid;
+	bool schedule = false;
+
+	read_irq(spa, &dsisr, &dar, &pe_handle);
+	trace_ocxl_fault(spa->spa_mem, pe_handle, dsisr, dar, -1);
+
+	WARN_ON(pe_handle > SPA_PE_MASK);
+	pe = spa->spa_mem + pe_handle;
+	pid = be32_to_cpu(pe->pid);
+	/* We could be reading all null values here if the PE is being
+	 * removed while an interrupt kicks in. It's not supposed to
+	 * happen if the driver notified the AFU to terminate the
+	 * PASID, and the AFU waited for pending operations before
+	 * acknowledging. But even if it happens, we won't find a
+	 * memory context below and fail silently, so it should be ok.
+	 */
+	if (!(dsisr & SPA_XSL_TF)) {
+		WARN(1, "Invalid xsl interrupt fault register %#llx\n", dsisr);
+		ack_irq(spa, ADDRESS_ERROR);
+		return IRQ_HANDLED;
+	}
+
+	rcu_read_lock();
+	pe_data = radix_tree_lookup(&spa->pe_tree, pe_handle);
+	if (!pe_data) {
+		/*
+		 * Could only happen if the driver didn't notify the
+		 * AFU about PASID termination before removing the PE,
+		 * or the AFU didn't wait for all memory access to
+		 * have completed.
+		 *
+		 * Either way, we fail early, but we shouldn't log an
+		 * error message, as it is a valid (if unexpected)
+		 * scenario
+		 */
+		rcu_read_unlock();
+		pr_debug("Unknown mm context for xsl interrupt\n");
+		ack_irq(spa, ADDRESS_ERROR);
+		return IRQ_HANDLED;
+	}
+
+	if (!pe_data->mm) {
+		/*
+		 * translation fault from a kernel context - an OpenCAPI
+		 * device tried to access a bad kernel address
+		 */
+		rcu_read_unlock();
+		pr_warn("Unresolved OpenCAPI xsl fault in kernel context\n");
+		ack_irq(spa, ADDRESS_ERROR);
+		return IRQ_HANDLED;
+	}
+	WARN_ON(pe_data->mm->context.id != pid);
+
+	if (mmget_not_zero(pe_data->mm)) {
+			spa->xsl_fault.pe = pe_handle;
+			spa->xsl_fault.dar = dar;
+			spa->xsl_fault.dsisr = dsisr;
+			spa->xsl_fault.pe_data = *pe_data;
+			schedule = true;
+			/* mm_users count released by bottom half */
+	}
+	rcu_read_unlock();
+	if (schedule)
+		schedule_work(&spa->xsl_fault.fault_work);
+	else
+		ack_irq(spa, ADDRESS_ERROR);
+	return IRQ_HANDLED;
+}
+
+static void unmap_irq_registers(struct spa *spa)
+{
+	pnv_ocxl_unmap_xsl_regs(spa->reg_dsisr, spa->reg_dar, spa->reg_tfc,
+				spa->reg_pe_handle);
+}
+
+static int map_irq_registers(struct pci_dev *dev, struct spa *spa)
+{
+	return pnv_ocxl_map_xsl_regs(dev, &spa->reg_dsisr, &spa->reg_dar,
+				&spa->reg_tfc, &spa->reg_pe_handle);
+}
+
+static int setup_xsl_irq(struct pci_dev *dev, struct ocxl_link *link)
+{
+	struct spa *spa = link->spa;
+	int rc;
+	int hwirq;
+
+	rc = pnv_ocxl_get_xsl_irq(dev, &hwirq);
+	if (rc)
+		return rc;
+
+	rc = map_irq_registers(dev, spa);
+	if (rc)
+		return rc;
+
+	spa->irq_name = kasprintf(GFP_KERNEL, "ocxl-xsl-%x-%x-%x",
+				link->domain, link->bus, link->dev);
+	if (!spa->irq_name) {
+		dev_err(&dev->dev, "Can't allocate name for xsl interrupt\n");
+		rc = -ENOMEM;
+		goto err_xsl;
+	}
+	/*
+	 * At some point, we'll need to look into allowing a higher
+	 * number of interrupts. Could we have an IRQ domain per link?
+	 */
+	spa->virq = irq_create_mapping(NULL, hwirq);
+	if (!spa->virq) {
+		dev_err(&dev->dev,
+			"irq_create_mapping failed for translation interrupt\n");
+		rc = -EINVAL;
+		goto err_name;
+	}
+
+	dev_dbg(&dev->dev, "hwirq %d mapped to virq %d\n", hwirq, spa->virq);
+
+	rc = request_irq(spa->virq, xsl_fault_handler, 0, spa->irq_name,
+			link);
+	if (rc) {
+		dev_err(&dev->dev,
+			"request_irq failed for translation interrupt: %d\n",
+			rc);
+		rc = -EINVAL;
+		goto err_mapping;
+	}
+	return 0;
+
+err_mapping:
+	irq_dispose_mapping(spa->virq);
+err_name:
+	kfree(spa->irq_name);
+err_xsl:
+	unmap_irq_registers(spa);
+	return rc;
+}
+
+static void release_xsl_irq(struct ocxl_link *link)
+{
+	struct spa *spa = link->spa;
+
+	if (spa->virq) {
+		free_irq(spa->virq, link);
+		irq_dispose_mapping(spa->virq);
+	}
+	kfree(spa->irq_name);
+	unmap_irq_registers(spa);
+}
+
+static int alloc_spa(struct pci_dev *dev, struct ocxl_link *link)
+{
+	struct spa *spa;
+
+	spa = kzalloc_obj(struct spa);
+	if (!spa)
+		return -ENOMEM;
+
+	mutex_init(&spa->spa_lock);
+	INIT_RADIX_TREE(&spa->pe_tree, GFP_KERNEL);
+	INIT_WORK(&spa->xsl_fault.fault_work, xsl_fault_handler_bh);
+
+	spa->spa_order = SPA_SPA_SIZE_LOG - PAGE_SHIFT;
+	spa->spa_mem = (struct ocxl_process_element *)
+		__get_free_pages(GFP_KERNEL | __GFP_ZERO, spa->spa_order);
+	if (!spa->spa_mem) {
+		dev_err(&dev->dev, "Can't allocate Shared Process Area\n");
+		kfree(spa);
+		return -ENOMEM;
+	}
+	pr_debug("Allocated SPA for %x:%x:%x at %p\n", link->domain, link->bus,
+		link->dev, spa->spa_mem);
+
+	link->spa = spa;
+	return 0;
+}
+
+static void free_spa(struct ocxl_link *link)
+{
+	struct spa *spa = link->spa;
+
+	pr_debug("Freeing SPA for %x:%x:%x\n", link->domain, link->bus,
+		link->dev);
+
+	if (spa && spa->spa_mem) {
+		free_pages((unsigned long) spa->spa_mem, spa->spa_order);
+		kfree(spa);
+		link->spa = NULL;
+	}
+}
+
+static int alloc_link(struct pci_dev *dev, int PE_mask, struct ocxl_link **out_link)
+{
+	struct ocxl_link *link;
+	int rc;
+
+	link = kzalloc_obj(struct ocxl_link);
+	if (!link)
+		return -ENOMEM;
+
+	kref_init(&link->ref);
+	link->domain = pci_domain_nr(dev->bus);
+	link->bus = dev->bus->number;
+	link->dev = PCI_SLOT(dev->devfn);
+	atomic_set(&link->irq_available, MAX_IRQ_PER_LINK);
+	spin_lock_init(&link->atsd_lock);
+
+	rc = alloc_spa(dev, link);
+	if (rc)
+		goto err_free;
+
+	rc = setup_xsl_irq(dev, link);
+	if (rc)
+		goto err_spa;
+
+	/* platform specific hook */
+	rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
+				&link->platform_data);
+	if (rc)
+		goto err_xsl_irq;
+
+	/* if link->arva is not defeined, MMIO registers are not used to
+	 * generate TLB invalidate. PowerBus snooping is enabled.
+	 * Otherwise, PowerBus snooping is disabled. TLB Invalidates are
+	 * initiated using MMIO registers.
+	 */
+	pnv_ocxl_map_lpar(dev, mfspr(SPRN_LPID), 0, &link->arva);
+
+	*out_link = link;
+	return 0;
+
+err_xsl_irq:
+	release_xsl_irq(link);
+err_spa:
+	free_spa(link);
+err_free:
+	kfree(link);
+	return rc;
+}
+
+static void free_link(struct ocxl_link *link)
+{
+	release_xsl_irq(link);
+	free_spa(link);
+	kfree(link);
+}
+
+int ocxl_link_setup(struct pci_dev *dev, int PE_mask, void **link_handle)
+{
+	int rc = 0;
+	struct ocxl_link *link;
+
+	mutex_lock(&links_list_lock);
+	list_for_each_entry(link, &links_list, list) {
+		/* The functions of a device all share the same link */
+		if (link->domain == pci_domain_nr(dev->bus) &&
+			link->bus == dev->bus->number &&
+			link->dev == PCI_SLOT(dev->devfn)) {
+			kref_get(&link->ref);
+			*link_handle = link;
+			goto unlock;
+		}
+	}
+	rc = alloc_link(dev, PE_mask, &link);
+	if (rc)
+		goto unlock;
+
+	list_add(&link->list, &links_list);
+	*link_handle = link;
+unlock:
+	mutex_unlock(&links_list_lock);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ocxl_link_setup);
+
+static void release_xsl(struct kref *ref)
+{
+	struct ocxl_link *link = container_of(ref, struct ocxl_link, ref);
+
+	if (link->arva) {
+		pnv_ocxl_unmap_lpar(link->arva);
+		link->arva = NULL;
+	}
+
+	list_del(&link->list);
+	/* call platform code before releasing data */
+	pnv_ocxl_spa_release(link->platform_data);
+	free_link(link);
+}
+
+void ocxl_link_release(struct pci_dev *dev, void *link_handle)
+{
+	struct ocxl_link *link = link_handle;
+
+	mutex_lock(&links_list_lock);
+	kref_put(&link->ref, release_xsl);
+	mutex_unlock(&links_list_lock);
+}
+EXPORT_SYMBOL_GPL(ocxl_link_release);
+
+static void arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
+					struct mm_struct *mm,
+					unsigned long start, unsigned long end)
+{
+	struct pe_data *pe_data = container_of(mn, struct pe_data, mmu_notifier);
+	struct ocxl_link *link = pe_data->link;
+	unsigned long addr, pid, page_size = PAGE_SIZE;
+
+	pid = mm->context.id;
+	trace_ocxl_mmu_notifier_range(start, end, pid);
+
+	spin_lock(&link->atsd_lock);
+	for (addr = start; addr < end; addr += page_size)
+		pnv_ocxl_tlb_invalidate(link->arva, pid, addr, page_size);
+	spin_unlock(&link->atsd_lock);
+}
+
+static const struct mmu_notifier_ops ocxl_mmu_notifier_ops = {
+	.arch_invalidate_secondary_tlbs = arch_invalidate_secondary_tlbs,
+};
+
+static u64 calculate_cfg_state(bool kernel)
+{
+	u64 state;
+
+	state = SPA_CFG_DR;
+	if (mfspr(SPRN_LPCR) & LPCR_TC)
+		state |= SPA_CFG_TC;
+	if (radix_enabled())
+		state |= SPA_CFG_XLAT_ror;
+	else
+		state |= SPA_CFG_XLAT_hpt;
+	state |= SPA_CFG_HV;
+	if (kernel) {
+		if (mfmsr() & MSR_SF)
+			state |= SPA_CFG_SF;
+	} else {
+		state |= SPA_CFG_PR;
+		if (!test_tsk_thread_flag(current, TIF_32BIT))
+			state |= SPA_CFG_SF;
+	}
+	return state;
+}
+
+int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
+		u64 amr, u16 bdf, struct mm_struct *mm,
+		void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr),
+		void *xsl_err_data)
+{
+	struct ocxl_link *link = link_handle;
+	struct spa *spa = link->spa;
+	struct ocxl_process_element *pe;
+	int pe_handle, rc = 0;
+	struct pe_data *pe_data;
+
+	BUILD_BUG_ON(sizeof(struct ocxl_process_element) != 128);
+	if (pasid > SPA_PASID_MAX)
+		return -EINVAL;
+
+	mutex_lock(&spa->spa_lock);
+	pe_handle = pasid & SPA_PE_MASK;
+	pe = spa->spa_mem + pe_handle;
+
+	if (pe->software_state) {
+		rc = -EBUSY;
+		goto unlock;
+	}
+
+	pe_data = kmalloc_obj(*pe_data);
+	if (!pe_data) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+
+	pe_data->mm = mm;
+	pe_data->xsl_err_cb = xsl_err_cb;
+	pe_data->xsl_err_data = xsl_err_data;
+	pe_data->link = link;
+	pe_data->mmu_notifier.ops = &ocxl_mmu_notifier_ops;
+
+	memset(pe, 0, sizeof(struct ocxl_process_element));
+	pe->config_state = cpu_to_be64(calculate_cfg_state(pidr == 0));
+	pe->pasid = cpu_to_be32(pasid << (31 - 19));
+	pe->bdf = cpu_to_be16(bdf);
+	pe->lpid = cpu_to_be32(mfspr(SPRN_LPID));
+	pe->pid = cpu_to_be32(pidr);
+	pe->tid = cpu_to_be32(tidr);
+	pe->amr = cpu_to_be64(amr);
+	pe->software_state = cpu_to_be32(SPA_PE_VALID);
+
+	/*
+	 * For user contexts, register a copro so that TLBIs are seen
+	 * by the nest MMU. If we have a kernel context, TLBIs are
+	 * already global.
+	 */
+	if (mm) {
+		mm_context_add_copro(mm);
+		if (link->arva) {
+			/* Use MMIO registers for the TLB Invalidate
+			 * operations.
+			 */
+			trace_ocxl_init_mmu_notifier(pasid, mm->context.id);
+			mmu_notifier_register(&pe_data->mmu_notifier, mm);
+		}
+	}
+
+	/*
+	 * Barrier is to make sure PE is visible in the SPA before it
+	 * is used by the device. It also helps with the global TLBI
+	 * invalidation
+	 */
+	mb();
+	radix_tree_insert(&spa->pe_tree, pe_handle, pe_data);
+
+	/*
+	 * The mm must stay valid for as long as the device uses it. We
+	 * lower the count when the context is removed from the SPA.
+	 *
+	 * We grab mm_count (and not mm_users), as we don't want to
+	 * end up in a circular dependency if a process mmaps its
+	 * mmio, therefore incrementing the file ref count when
+	 * calling mmap(), and forgets to unmap before exiting. In
+	 * that scenario, when the kernel handles the death of the
+	 * process, the file is not cleaned because unmap was not
+	 * called, and the mm wouldn't be freed because we would still
+	 * have a reference on mm_users. Incrementing mm_count solves
+	 * the problem.
+	 */
+	if (mm)
+		mmgrab(mm);
+	trace_ocxl_context_add(current->pid, spa->spa_mem, pasid, pidr, tidr);
+unlock:
+	mutex_unlock(&spa->spa_lock);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ocxl_link_add_pe);
+
+int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid)
+{
+	struct ocxl_link *link = link_handle;
+	struct spa *spa = link->spa;
+	struct ocxl_process_element *pe;
+	int pe_handle, rc;
+
+	if (pasid > SPA_PASID_MAX)
+		return -EINVAL;
+
+	pe_handle = pasid & SPA_PE_MASK;
+	pe = spa->spa_mem + pe_handle;
+
+	mutex_lock(&spa->spa_lock);
+
+	pe->tid = cpu_to_be32(tid);
+
+	/*
+	 * The barrier makes sure the PE is updated
+	 * before we clear the NPU context cache below, so that the
+	 * old PE cannot be reloaded erroneously.
+	 */
+	mb();
+
+	/*
+	 * hook to platform code
+	 * On powerpc, the entry needs to be cleared from the context
+	 * cache of the NPU.
+	 */
+	rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
+	WARN_ON(rc);
+
+	mutex_unlock(&spa->spa_lock);
+	return rc;
+}
+
+int ocxl_link_remove_pe(void *link_handle, int pasid)
+{
+	struct ocxl_link *link = link_handle;
+	struct spa *spa = link->spa;
+	struct ocxl_process_element *pe;
+	struct pe_data *pe_data;
+	int pe_handle, rc;
+
+	if (pasid > SPA_PASID_MAX)
+		return -EINVAL;
+
+	/*
+	 * About synchronization with our memory fault handler:
+	 *
+	 * Before removing the PE, the driver is supposed to have
+	 * notified the AFU, which should have cleaned up and make
+	 * sure the PASID is no longer in use, including pending
+	 * interrupts. However, there's no way to be sure...
+	 *
+	 * We clear the PE and remove the context from our radix
+	 * tree. From that point on, any new interrupt for that
+	 * context will fail silently, which is ok. As mentioned
+	 * above, that's not expected, but it could happen if the
+	 * driver or AFU didn't do the right thing.
+	 *
+	 * There could still be a bottom half running, but we don't
+	 * need to wait/flush, as it is managing a reference count on
+	 * the mm it reads from the radix tree.
+	 */
+	pe_handle = pasid & SPA_PE_MASK;
+	pe = spa->spa_mem + pe_handle;
+
+	mutex_lock(&spa->spa_lock);
+
+	if (!(be32_to_cpu(pe->software_state) & SPA_PE_VALID)) {
+		rc = -EINVAL;
+		goto unlock;
+	}
+
+	trace_ocxl_context_remove(current->pid, spa->spa_mem, pasid,
+				be32_to_cpu(pe->pid), be32_to_cpu(pe->tid));
+
+	memset(pe, 0, sizeof(struct ocxl_process_element));
+	/*
+	 * The barrier makes sure the PE is removed from the SPA
+	 * before we clear the NPU context cache below, so that the
+	 * old PE cannot be reloaded erroneously.
+	 */
+	mb();
+
+	/*
+	 * hook to platform code
+	 * On powerpc, the entry needs to be cleared from the context
+	 * cache of the NPU.
+	 */
+	rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, pe_handle);
+	WARN_ON(rc);
+
+	pe_data = radix_tree_delete(&spa->pe_tree, pe_handle);
+	if (!pe_data) {
+		WARN(1, "Couldn't find pe data when removing PE\n");
+	} else {
+		if (pe_data->mm) {
+			if (link->arva) {
+				trace_ocxl_release_mmu_notifier(pasid,
+								pe_data->mm->context.id);
+				mmu_notifier_unregister(&pe_data->mmu_notifier,
+							pe_data->mm);
+				spin_lock(&link->atsd_lock);
+				pnv_ocxl_tlb_invalidate(link->arva,
+							pe_data->mm->context.id,
+							0ull,
+							PAGE_SIZE);
+				spin_unlock(&link->atsd_lock);
+			}
+			mm_context_remove_copro(pe_data->mm);
+			mmdrop(pe_data->mm);
+		}
+		kfree_rcu(pe_data, rcu);
+	}
+unlock:
+	mutex_unlock(&spa->spa_lock);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ocxl_link_remove_pe);
+
+int ocxl_link_irq_alloc(void *link_handle, int *hw_irq)
+{
+	struct ocxl_link *link = link_handle;
+	int irq;
+
+	if (atomic_dec_if_positive(&link->irq_available) < 0)
+		return -ENOSPC;
+
+	irq = xive_native_alloc_irq();
+	if (!irq) {
+		atomic_inc(&link->irq_available);
+		return -ENXIO;
+	}
+
+	*hw_irq = irq;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ocxl_link_irq_alloc);
+
+void ocxl_link_free_irq(void *link_handle, int hw_irq)
+{
+	struct ocxl_link *link = link_handle;
+
+	xive_native_free_irq(hw_irq);
+	atomic_inc(&link->irq_available);
+}
+EXPORT_SYMBOL_GPL(ocxl_link_free_irq);