diff options
Diffstat (limited to 'drivers/misc/cxl/file.c')
-rw-r--r-- | drivers/misc/cxl/file.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c new file mode 100644 index 000000000..bd3bd3233 --- /dev/null +++ b/drivers/misc/cxl/file.c @@ -0,0 +1,699 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2014 IBM Corp. + */ + +#include <linux/spinlock.h> +#include <linux/module.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/bitmap.h> +#include <linux/sched/signal.h> +#include <linux/poll.h> +#include <linux/pid.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/sched/mm.h> +#include <linux/mmu_context.h> +#include <asm/cputable.h> +#include <asm/current.h> +#include <asm/copro.h> + +#include "cxl.h" +#include "trace.h" + +#define CXL_NUM_MINORS 256 /* Total to reserve */ + +#define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice)) +#define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1) +#define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2) +#define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu)) +#define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu)) +#define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu)) + +#define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3) + +#define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0) + +static dev_t cxl_dev; + +static struct class *cxl_class; + +static int __afu_open(struct inode *inode, struct file *file, bool master) +{ + struct cxl *adapter; + struct cxl_afu *afu; + struct cxl_context *ctx; + int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev); + int slice = CXL_DEVT_AFU(inode->i_rdev); + int rc = -ENODEV; + + pr_devel("afu_open afu%i.%i\n", slice, adapter_num); + + if (!(adapter = get_cxl_adapter(adapter_num))) + return -ENODEV; + + if (slice > adapter->slices) + goto err_put_adapter; + + spin_lock(&adapter->afu_list_lock); + if (!(afu = adapter->afu[slice])) { + spin_unlock(&adapter->afu_list_lock); + goto err_put_adapter; + } + + /* + * taking a ref to the afu so that it doesn't go away + * for rest of the function. This ref is released before + * we return. + */ + cxl_afu_get(afu); + spin_unlock(&adapter->afu_list_lock); + + if (!afu->current_mode) + goto err_put_afu; + + if (!cxl_ops->link_ok(adapter, afu)) { + rc = -EIO; + goto err_put_afu; + } + + if (!(ctx = cxl_context_alloc())) { + rc = -ENOMEM; + goto err_put_afu; + } + + rc = cxl_context_init(ctx, afu, master); + if (rc) + goto err_put_afu; + + cxl_context_set_mapping(ctx, inode->i_mapping); + + pr_devel("afu_open pe: %i\n", ctx->pe); + file->private_data = ctx; + + /* indicate success */ + rc = 0; + +err_put_afu: + /* release the ref taken earlier */ + cxl_afu_put(afu); +err_put_adapter: + put_device(&adapter->dev); + return rc; +} + +int afu_open(struct inode *inode, struct file *file) +{ + return __afu_open(inode, file, false); +} + +static int afu_master_open(struct inode *inode, struct file *file) +{ + return __afu_open(inode, file, true); +} + +int afu_release(struct inode *inode, struct file *file) +{ + struct cxl_context *ctx = file->private_data; + + pr_devel("%s: closing cxl file descriptor. pe: %i\n", + __func__, ctx->pe); + cxl_context_detach(ctx); + + + /* + * Delete the context's mapping pointer, unless it's created by the + * kernel API, in which case leave it so it can be freed by reclaim_ctx() + */ + if (!ctx->kernelapi) { + mutex_lock(&ctx->mapping_lock); + ctx->mapping = NULL; + mutex_unlock(&ctx->mapping_lock); + } + + /* + * At this this point all bottom halfs have finished and we should be + * getting no more IRQs from the hardware for this context. Once it's + * removed from the IDR (and RCU synchronised) it's safe to free the + * sstp and context. + */ + cxl_context_free(ctx); + + return 0; +} + +static long afu_ioctl_start_work(struct cxl_context *ctx, + struct cxl_ioctl_start_work __user *uwork) +{ + struct cxl_ioctl_start_work work; + u64 amr = 0; + int rc; + + pr_devel("%s: pe: %i\n", __func__, ctx->pe); + + /* Do this outside the status_mutex to avoid a circular dependency with + * the locking in cxl_mmap_fault() */ + if (copy_from_user(&work, uwork, sizeof(work))) + return -EFAULT; + + mutex_lock(&ctx->status_mutex); + if (ctx->status != OPENED) { + rc = -EIO; + goto out; + } + + /* + * if any of the reserved fields are set or any of the unused + * flags are set it's invalid + */ + if (work.reserved1 || work.reserved2 || work.reserved3 || + work.reserved4 || work.reserved5 || + (work.flags & ~CXL_START_WORK_ALL)) { + rc = -EINVAL; + goto out; + } + + if (!(work.flags & CXL_START_WORK_NUM_IRQS)) + work.num_interrupts = ctx->afu->pp_irqs; + else if ((work.num_interrupts < ctx->afu->pp_irqs) || + (work.num_interrupts > ctx->afu->irqs_max)) { + rc = -EINVAL; + goto out; + } + + if ((rc = afu_register_irqs(ctx, work.num_interrupts))) + goto out; + + if (work.flags & CXL_START_WORK_AMR) + amr = work.amr & mfspr(SPRN_UAMOR); + + if (work.flags & CXL_START_WORK_TID) + ctx->assign_tidr = true; + + ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF); + + /* + * Increment the mapped context count for adapter. This also checks + * if adapter_context_lock is taken. + */ + rc = cxl_adapter_context_get(ctx->afu->adapter); + if (rc) { + afu_release_irqs(ctx, ctx); + goto out; + } + + /* + * We grab the PID here and not in the file open to allow for the case + * where a process (master, some daemon, etc) has opened the chardev on + * behalf of another process, so the AFU's mm gets bound to the process + * that performs this ioctl and not the process that opened the file. + * Also we grab the PID of the group leader so that if the task that + * has performed the attach operation exits the mm context of the + * process is still accessible. + */ + ctx->pid = get_task_pid(current, PIDTYPE_PID); + + /* acquire a reference to the task's mm */ + ctx->mm = get_task_mm(current); + + /* ensure this mm_struct can't be freed */ + cxl_context_mm_count_get(ctx); + + if (ctx->mm) { + /* decrement the use count from above */ + mmput(ctx->mm); + /* make TLBIs for this context global */ + mm_context_add_copro(ctx->mm); + } + + /* + * Increment driver use count. Enables global TLBIs for hash + * and callbacks to handle the segment table + */ + cxl_ctx_get(); + + /* + * A barrier is needed to make sure all TLBIs are global + * before we attach and the context starts being used by the + * adapter. + * + * Needed after mm_context_add_copro() for radix and + * cxl_ctx_get() for hash/p8. + * + * The barrier should really be mb(), since it involves a + * device. However, it's only useful when we have local + * vs. global TLBIs, i.e SMP=y. So keep smp_mb(). + */ + smp_mb(); + + trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr); + + if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor, + amr))) { + afu_release_irqs(ctx, ctx); + cxl_adapter_context_put(ctx->afu->adapter); + put_pid(ctx->pid); + ctx->pid = NULL; + cxl_ctx_put(); + cxl_context_mm_count_put(ctx); + if (ctx->mm) + mm_context_remove_copro(ctx->mm); + goto out; + } + + rc = 0; + if (work.flags & CXL_START_WORK_TID) { + work.tid = ctx->tidr; + if (copy_to_user(uwork, &work, sizeof(work))) + rc = -EFAULT; + } + + ctx->status = STARTED; + +out: + mutex_unlock(&ctx->status_mutex); + return rc; +} + +static long afu_ioctl_process_element(struct cxl_context *ctx, + int __user *upe) +{ + pr_devel("%s: pe: %i\n", __func__, ctx->pe); + + if (copy_to_user(upe, &ctx->external_pe, sizeof(__u32))) + return -EFAULT; + + return 0; +} + +static long afu_ioctl_get_afu_id(struct cxl_context *ctx, + struct cxl_afu_id __user *upafuid) +{ + struct cxl_afu_id afuid = { 0 }; + + afuid.card_id = ctx->afu->adapter->adapter_num; + afuid.afu_offset = ctx->afu->slice; + afuid.afu_mode = ctx->afu->current_mode; + + /* set the flag bit in case the afu is a slave */ + if (ctx->afu->current_mode == CXL_MODE_DIRECTED && !ctx->master) + afuid.flags |= CXL_AFUID_FLAG_SLAVE; + + if (copy_to_user(upafuid, &afuid, sizeof(afuid))) + return -EFAULT; + + return 0; +} + +long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct cxl_context *ctx = file->private_data; + + if (ctx->status == CLOSED) + return -EIO; + + if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) + return -EIO; + + pr_devel("afu_ioctl\n"); + switch (cmd) { + case CXL_IOCTL_START_WORK: + return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg); + case CXL_IOCTL_GET_PROCESS_ELEMENT: + return afu_ioctl_process_element(ctx, (__u32 __user *)arg); + case CXL_IOCTL_GET_AFU_ID: + return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *) + arg); + } + return -EINVAL; +} + +static long afu_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return afu_ioctl(file, cmd, arg); +} + +int afu_mmap(struct file *file, struct vm_area_struct *vm) +{ + struct cxl_context *ctx = file->private_data; + + /* AFU must be started before we can MMIO */ + if (ctx->status != STARTED) + return -EIO; + + if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) + return -EIO; + + return cxl_context_iomap(ctx, vm); +} + +static inline bool ctx_event_pending(struct cxl_context *ctx) +{ + if (ctx->pending_irq || ctx->pending_fault || ctx->pending_afu_err) + return true; + + if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events)) + return true; + + return false; +} + +__poll_t afu_poll(struct file *file, struct poll_table_struct *poll) +{ + struct cxl_context *ctx = file->private_data; + __poll_t mask = 0; + unsigned long flags; + + + poll_wait(file, &ctx->wq, poll); + + pr_devel("afu_poll wait done pe: %i\n", ctx->pe); + + spin_lock_irqsave(&ctx->lock, flags); + if (ctx_event_pending(ctx)) + mask |= EPOLLIN | EPOLLRDNORM; + else if (ctx->status == CLOSED) + /* Only error on closed when there are no futher events pending + */ + mask |= EPOLLERR; + spin_unlock_irqrestore(&ctx->lock, flags); + + pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask); + + return mask; +} + +static ssize_t afu_driver_event_copy(struct cxl_context *ctx, + char __user *buf, + struct cxl_event *event, + struct cxl_event_afu_driver_reserved *pl) +{ + /* Check event */ + if (!pl) { + ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL); + return -EFAULT; + } + + /* Check event size */ + event->header.size += pl->data_size; + if (event->header.size > CXL_READ_MIN_SIZE) { + ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL); + return -EFAULT; + } + + /* Copy event header */ + if (copy_to_user(buf, event, sizeof(struct cxl_event_header))) { + ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT); + return -EFAULT; + } + + /* Copy event data */ + buf += sizeof(struct cxl_event_header); + if (copy_to_user(buf, &pl->data, pl->data_size)) { + ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT); + return -EFAULT; + } + + ctx->afu_driver_ops->event_delivered(ctx, pl, 0); /* Success */ + return event->header.size; +} + +ssize_t afu_read(struct file *file, char __user *buf, size_t count, + loff_t *off) +{ + struct cxl_context *ctx = file->private_data; + struct cxl_event_afu_driver_reserved *pl = NULL; + struct cxl_event event; + unsigned long flags; + int rc; + DEFINE_WAIT(wait); + + if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) + return -EIO; + + if (count < CXL_READ_MIN_SIZE) + return -EINVAL; + + spin_lock_irqsave(&ctx->lock, flags); + + for (;;) { + prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE); + if (ctx_event_pending(ctx) || (ctx->status == CLOSED)) + break; + + if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) { + rc = -EIO; + goto out; + } + + if (file->f_flags & O_NONBLOCK) { + rc = -EAGAIN; + goto out; + } + + if (signal_pending(current)) { + rc = -ERESTARTSYS; + goto out; + } + + spin_unlock_irqrestore(&ctx->lock, flags); + pr_devel("afu_read going to sleep...\n"); + schedule(); + pr_devel("afu_read woken up\n"); + spin_lock_irqsave(&ctx->lock, flags); + } + + finish_wait(&ctx->wq, &wait); + + memset(&event, 0, sizeof(event)); + event.header.process_element = ctx->pe; + event.header.size = sizeof(struct cxl_event_header); + if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events)) { + pr_devel("afu_read delivering AFU driver specific event\n"); + pl = ctx->afu_driver_ops->fetch_event(ctx); + atomic_dec(&ctx->afu_driver_events); + event.header.type = CXL_EVENT_AFU_DRIVER; + } else if (ctx->pending_irq) { + pr_devel("afu_read delivering AFU interrupt\n"); + event.header.size += sizeof(struct cxl_event_afu_interrupt); + event.header.type = CXL_EVENT_AFU_INTERRUPT; + event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1; + clear_bit(event.irq.irq - 1, ctx->irq_bitmap); + if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count)) + ctx->pending_irq = false; + } else if (ctx->pending_fault) { + pr_devel("afu_read delivering data storage fault\n"); + event.header.size += sizeof(struct cxl_event_data_storage); + event.header.type = CXL_EVENT_DATA_STORAGE; + event.fault.addr = ctx->fault_addr; + event.fault.dsisr = ctx->fault_dsisr; + ctx->pending_fault = false; + } else if (ctx->pending_afu_err) { + pr_devel("afu_read delivering afu error\n"); + event.header.size += sizeof(struct cxl_event_afu_error); + event.header.type = CXL_EVENT_AFU_ERROR; + event.afu_error.error = ctx->afu_err; + ctx->pending_afu_err = false; + } else if (ctx->status == CLOSED) { + pr_devel("afu_read fatal error\n"); + spin_unlock_irqrestore(&ctx->lock, flags); + return -EIO; + } else + WARN(1, "afu_read must be buggy\n"); + + spin_unlock_irqrestore(&ctx->lock, flags); + + if (event.header.type == CXL_EVENT_AFU_DRIVER) + return afu_driver_event_copy(ctx, buf, &event, pl); + + if (copy_to_user(buf, &event, event.header.size)) + return -EFAULT; + return event.header.size; + +out: + finish_wait(&ctx->wq, &wait); + spin_unlock_irqrestore(&ctx->lock, flags); + return rc; +} + +/* + * Note: if this is updated, we need to update api.c to patch the new ones in + * too + */ +const struct file_operations afu_fops = { + .owner = THIS_MODULE, + .open = afu_open, + .poll = afu_poll, + .read = afu_read, + .release = afu_release, + .unlocked_ioctl = afu_ioctl, + .compat_ioctl = afu_compat_ioctl, + .mmap = afu_mmap, +}; + +static const struct file_operations afu_master_fops = { + .owner = THIS_MODULE, + .open = afu_master_open, + .poll = afu_poll, + .read = afu_read, + .release = afu_release, + .unlocked_ioctl = afu_ioctl, + .compat_ioctl = afu_compat_ioctl, + .mmap = afu_mmap, +}; + + +static char *cxl_devnode(struct device *dev, umode_t *mode) +{ + if (cpu_has_feature(CPU_FTR_HVMODE) && + CXL_DEVT_IS_CARD(dev->devt)) { + /* + * These minor numbers will eventually be used to program the + * PSL and AFUs once we have dynamic reprogramming support + */ + return NULL; + } + return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev)); +} + +extern struct class *cxl_class; + +static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev, + struct device **chardev, char *postfix, char *desc, + const struct file_operations *fops) +{ + struct device *dev; + int rc; + + cdev_init(cdev, fops); + if ((rc = cdev_add(cdev, devt, 1))) { + dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc); + return rc; + } + + dev = device_create(cxl_class, &afu->dev, devt, afu, + "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix); + if (IS_ERR(dev)) { + dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc); + rc = PTR_ERR(dev); + goto err; + } + + *chardev = dev; + + return 0; +err: + cdev_del(cdev); + return rc; +} + +int cxl_chardev_d_afu_add(struct cxl_afu *afu) +{ + return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d, + &afu->chardev_d, "d", "dedicated", + &afu_master_fops); /* Uses master fops */ +} + +int cxl_chardev_m_afu_add(struct cxl_afu *afu) +{ + return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m, + &afu->chardev_m, "m", "master", + &afu_master_fops); +} + +int cxl_chardev_s_afu_add(struct cxl_afu *afu) +{ + return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s, + &afu->chardev_s, "s", "shared", + &afu_fops); +} + +void cxl_chardev_afu_remove(struct cxl_afu *afu) +{ + if (afu->chardev_d) { + cdev_del(&afu->afu_cdev_d); + device_unregister(afu->chardev_d); + afu->chardev_d = NULL; + } + if (afu->chardev_m) { + cdev_del(&afu->afu_cdev_m); + device_unregister(afu->chardev_m); + afu->chardev_m = NULL; + } + if (afu->chardev_s) { + cdev_del(&afu->afu_cdev_s); + device_unregister(afu->chardev_s); + afu->chardev_s = NULL; + } +} + +int cxl_register_afu(struct cxl_afu *afu) +{ + afu->dev.class = cxl_class; + + return device_register(&afu->dev); +} + +int cxl_register_adapter(struct cxl *adapter) +{ + adapter->dev.class = cxl_class; + + /* + * Future: When we support dynamically reprogramming the PSL & AFU we + * will expose the interface to do that via a chardev: + * adapter->dev.devt = CXL_CARD_MKDEV(adapter); + */ + + return device_register(&adapter->dev); +} + +dev_t cxl_get_dev(void) +{ + return cxl_dev; +} + +int __init cxl_file_init(void) +{ + int rc; + + /* + * If these change we really need to update API. Either change some + * flags or update API version number CXL_API_VERSION. + */ + BUILD_BUG_ON(CXL_API_VERSION != 3); + BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64); + BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8); + BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8); + BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32); + BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16); + + if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) { + pr_err("Unable to allocate CXL major number: %i\n", rc); + return rc; + } + + pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev)); + + cxl_class = class_create(THIS_MODULE, "cxl"); + if (IS_ERR(cxl_class)) { + pr_err("Unable to create CXL class\n"); + rc = PTR_ERR(cxl_class); + goto err; + } + cxl_class->devnode = cxl_devnode; + + return 0; + +err: + unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS); + return rc; +} + +void cxl_file_exit(void) +{ + unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS); + class_destroy(cxl_class); +} |