diff options
Diffstat (limited to 'drivers/misc/ocxl/link.c')
| -rw-r--r-- | drivers/misc/ocxl/link.c | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c new file mode 100644 index 000000000000..f30790582dc0 --- /dev/null +++ b/drivers/misc/ocxl/link.c @@ -0,0 +1,647 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Copyright 2017 IBM Corp. +#include <linux/sched/mm.h> +#include <linux/mutex.h> +#include <linux/mmu_context.h> +#include <asm/copro.h> +#include <asm/pnv-ocxl.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 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 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 link { + struct list_head list; + struct kref ref; + int domain; + int bus; + int dev; + atomic_t irq_available; + struct spa *spa; + void *platform_data; +}; +static struct list_head links_list = LIST_HEAD_INIT(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) +{ + unsigned int 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 need to release a reference on the mm 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 (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: + mmdrop(fault->pe_data.mm); + ack_irq(spa, r); +} + +static irqreturn_t xsl_fault_handler(int irq, void *data) +{ + struct link *link = (struct link *) data; + struct spa *spa = link->spa; + u64 dsisr, dar, pe_handle; + struct pe_data *pe_data; + struct ocxl_process_element *pe; + int lpid, pid, tid; + + 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; + lpid = be32_to_cpu(pe->lpid); + pid = be32_to_cpu(pe->pid); + tid = be32_to_cpu(pe->tid); + /* 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; + } + WARN_ON(pe_data->mm->context.id != pid); + + spa->xsl_fault.pe = pe_handle; + spa->xsl_fault.dar = dar; + spa->xsl_fault.dsisr = dsisr; + spa->xsl_fault.pe_data = *pe_data; + mmgrab(pe_data->mm); /* mm count is released by bottom half */ + + rcu_read_unlock(); + schedule_work(&spa->xsl_fault.fault_work); + 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 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) { + unmap_irq_registers(spa); + dev_err(&dev->dev, "Can't allocate name for xsl interrupt\n"); + return -ENOMEM; + } + /* + * 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) { + kfree(spa->irq_name); + unmap_irq_registers(spa); + dev_err(&dev->dev, + "irq_create_mapping failed for translation interrupt\n"); + return -EINVAL; + } + + 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) { + irq_dispose_mapping(spa->virq); + kfree(spa->irq_name); + unmap_irq_registers(spa); + dev_err(&dev->dev, + "request_irq failed for translation interrupt: %d\n", + rc); + return -EINVAL; + } + return 0; +} + +static void release_xsl_irq(struct 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 link *link) +{ + struct spa *spa; + + spa = kzalloc(sizeof(struct spa), GFP_KERNEL); + 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 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 link **out_link) +{ + struct link *link; + int rc; + + link = kzalloc(sizeof(struct link), GFP_KERNEL); + 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); + + 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; + + *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 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 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 link *link = container_of(ref, struct link, ref); + + 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 link *link = (struct 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 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, struct mm_struct *mm, + void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr), + void *xsl_err_data) +{ + struct link *link = (struct 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(sizeof(*pe_data), GFP_KERNEL); + 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; + + memset(pe, 0, sizeof(struct ocxl_process_element)); + pe->config_state = cpu_to_be64(calculate_cfg_state(pidr == 0)); + 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); + + mm_context_add_copro(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. + */ + 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_remove_pe(void *link_handle, int pasid) +{ + struct link *link = (struct 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(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 { + 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, u64 *trigger_addr) +{ + struct link *link = (struct link *) link_handle; + int rc, irq; + u64 addr; + + if (atomic_dec_if_positive(&link->irq_available) < 0) + return -ENOSPC; + + rc = pnv_ocxl_alloc_xive_irq(&irq, &addr); + if (rc) { + atomic_inc(&link->irq_available); + return rc; + } + + *hw_irq = irq; + *trigger_addr = addr; + return 0; +} +EXPORT_SYMBOL_GPL(ocxl_link_irq_alloc); + +void ocxl_link_free_irq(void *link_handle, int hw_irq) +{ + struct link *link = (struct link *) link_handle; + + pnv_ocxl_free_xive_irq(hw_irq); + atomic_inc(&link->irq_available); +} +EXPORT_SYMBOL_GPL(ocxl_link_free_irq); |