diff options
Diffstat (limited to 'drivers/misc/ocxl/file.c')
| -rw-r--r-- | drivers/misc/ocxl/file.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c new file mode 100644 index 000000000000..c90c1a578d2f --- /dev/null +++ b/drivers/misc/ocxl/file.c @@ -0,0 +1,432 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Copyright 2017 IBM Corp. +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/sched/signal.h> +#include <linux/uaccess.h> +#include <uapi/misc/ocxl.h> +#include "ocxl_internal.h" + + +#define OCXL_NUM_MINORS 256 /* Total to reserve */ + +static dev_t ocxl_dev; +static struct class *ocxl_class; +static struct mutex minors_idr_lock; +static struct idr minors_idr; + +static struct ocxl_afu *find_and_get_afu(dev_t devno) +{ + struct ocxl_afu *afu; + int afu_minor; + + afu_minor = MINOR(devno); + /* + * We don't declare an RCU critical section here, as our AFU + * is protected by a reference counter on the device. By the time the + * minor number of a device is removed from the idr, the ref count of + * the device is already at 0, so no user API will access that AFU and + * this function can't return it. + */ + afu = idr_find(&minors_idr, afu_minor); + if (afu) + ocxl_afu_get(afu); + return afu; +} + +static int allocate_afu_minor(struct ocxl_afu *afu) +{ + int minor; + + mutex_lock(&minors_idr_lock); + minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL); + mutex_unlock(&minors_idr_lock); + return minor; +} + +static void free_afu_minor(struct ocxl_afu *afu) +{ + mutex_lock(&minors_idr_lock); + idr_remove(&minors_idr, MINOR(afu->dev.devt)); + mutex_unlock(&minors_idr_lock); +} + +static int afu_open(struct inode *inode, struct file *file) +{ + struct ocxl_afu *afu; + struct ocxl_context *ctx; + int rc; + + pr_debug("%s for device %x\n", __func__, inode->i_rdev); + + afu = find_and_get_afu(inode->i_rdev); + if (!afu) + return -ENODEV; + + ctx = ocxl_context_alloc(); + if (!ctx) { + rc = -ENOMEM; + goto put_afu; + } + + rc = ocxl_context_init(ctx, afu, inode->i_mapping); + if (rc) + goto put_afu; + file->private_data = ctx; + ocxl_afu_put(afu); + return 0; + +put_afu: + ocxl_afu_put(afu); + return rc; +} + +static long afu_ioctl_attach(struct ocxl_context *ctx, + struct ocxl_ioctl_attach __user *uarg) +{ + struct ocxl_ioctl_attach arg; + u64 amr = 0; + int rc; + + pr_debug("%s for context %d\n", __func__, ctx->pasid); + + if (copy_from_user(&arg, uarg, sizeof(arg))) + return -EFAULT; + + /* Make sure reserved fields are not set for forward compatibility */ + if (arg.reserved1 || arg.reserved2 || arg.reserved3) + return -EINVAL; + + amr = arg.amr & mfspr(SPRN_UAMOR); + rc = ocxl_context_attach(ctx, amr); + return rc; +} + +#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" : \ + x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" : \ + x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \ + x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \ + "UNKNOWN") + +static long afu_ioctl(struct file *file, unsigned int cmd, + unsigned long args) +{ + struct ocxl_context *ctx = file->private_data; + struct ocxl_ioctl_irq_fd irq_fd; + u64 irq_offset; + long rc; + + pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid, + CMD_STR(cmd)); + + if (ctx->status == CLOSED) + return -EIO; + + switch (cmd) { + case OCXL_IOCTL_ATTACH: + rc = afu_ioctl_attach(ctx, + (struct ocxl_ioctl_attach __user *) args); + break; + + case OCXL_IOCTL_IRQ_ALLOC: + rc = ocxl_afu_irq_alloc(ctx, &irq_offset); + if (!rc) { + rc = copy_to_user((u64 __user *) args, &irq_offset, + sizeof(irq_offset)); + if (rc) + ocxl_afu_irq_free(ctx, irq_offset); + } + break; + + case OCXL_IOCTL_IRQ_FREE: + rc = copy_from_user(&irq_offset, (u64 __user *) args, + sizeof(irq_offset)); + if (rc) + return -EFAULT; + rc = ocxl_afu_irq_free(ctx, irq_offset); + break; + + case OCXL_IOCTL_IRQ_SET_FD: + rc = copy_from_user(&irq_fd, (u64 __user *) args, + sizeof(irq_fd)); + if (rc) + return -EFAULT; + if (irq_fd.reserved) + return -EINVAL; + rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset, + irq_fd.eventfd); + break; + + default: + rc = -EINVAL; + } + return rc; +} + +static long afu_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long args) +{ + return afu_ioctl(file, cmd, args); +} + +static int afu_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct ocxl_context *ctx = file->private_data; + + pr_debug("%s for context %d\n", __func__, ctx->pasid); + return ocxl_context_mmap(ctx, vma); +} + +static bool has_xsl_error(struct ocxl_context *ctx) +{ + bool ret; + + mutex_lock(&ctx->xsl_error_lock); + ret = !!ctx->xsl_error.addr; + mutex_unlock(&ctx->xsl_error_lock); + + return ret; +} + +/* + * Are there any events pending on the AFU + * ctx: The AFU context + * Returns: true if there are events pending + */ +static bool afu_events_pending(struct ocxl_context *ctx) +{ + if (has_xsl_error(ctx)) + return true; + return false; +} + +static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait) +{ + struct ocxl_context *ctx = file->private_data; + unsigned int mask = 0; + bool closed; + + pr_debug("%s for context %d\n", __func__, ctx->pasid); + + poll_wait(file, &ctx->events_wq, wait); + + mutex_lock(&ctx->status_mutex); + closed = (ctx->status == CLOSED); + mutex_unlock(&ctx->status_mutex); + + if (afu_events_pending(ctx)) + mask = POLLIN | POLLRDNORM; + else if (closed) + mask = POLLERR; + + return mask; +} + +/* + * Populate the supplied buffer with a single XSL error + * ctx: The AFU context to report the error from + * header: the event header to populate + * buf: The buffer to write the body into (should be at least + * AFU_EVENT_BODY_XSL_ERROR_SIZE) + * Return: the amount of buffer that was populated + */ +static ssize_t append_xsl_error(struct ocxl_context *ctx, + struct ocxl_kernel_event_header *header, + char __user *buf) +{ + struct ocxl_kernel_event_xsl_fault_error body; + + memset(&body, 0, sizeof(body)); + + mutex_lock(&ctx->xsl_error_lock); + if (!ctx->xsl_error.addr) { + mutex_unlock(&ctx->xsl_error_lock); + return 0; + } + + body.addr = ctx->xsl_error.addr; + body.dsisr = ctx->xsl_error.dsisr; + body.count = ctx->xsl_error.count; + + ctx->xsl_error.addr = 0; + ctx->xsl_error.dsisr = 0; + ctx->xsl_error.count = 0; + + mutex_unlock(&ctx->xsl_error_lock); + + header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR; + + if (copy_to_user(buf, &body, sizeof(body))) + return -EFAULT; + + return sizeof(body); +} + +#define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error) + +/* + * Reports events on the AFU + * Format: + * Header (struct ocxl_kernel_event_header) + * Body (struct ocxl_kernel_event_*) + * Header... + */ +static ssize_t afu_read(struct file *file, char __user *buf, size_t count, + loff_t *off) +{ + struct ocxl_context *ctx = file->private_data; + struct ocxl_kernel_event_header header; + ssize_t rc; + size_t used = 0; + DEFINE_WAIT(event_wait); + + memset(&header, 0, sizeof(header)); + + /* Require offset to be 0 */ + if (*off != 0) + return -EINVAL; + + if (count < (sizeof(struct ocxl_kernel_event_header) + + AFU_EVENT_BODY_MAX_SIZE)) + return -EINVAL; + + for (;;) { + prepare_to_wait(&ctx->events_wq, &event_wait, + TASK_INTERRUPTIBLE); + + if (afu_events_pending(ctx)) + break; + + if (ctx->status == CLOSED) + break; + + if (file->f_flags & O_NONBLOCK) { + finish_wait(&ctx->events_wq, &event_wait); + return -EAGAIN; + } + + if (signal_pending(current)) { + finish_wait(&ctx->events_wq, &event_wait); + return -ERESTARTSYS; + } + + schedule(); + } + + finish_wait(&ctx->events_wq, &event_wait); + + if (has_xsl_error(ctx)) { + used = append_xsl_error(ctx, &header, buf + sizeof(header)); + if (used < 0) + return used; + } + + if (!afu_events_pending(ctx)) + header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST; + + if (copy_to_user(buf, &header, sizeof(header))) + return -EFAULT; + + used += sizeof(header); + + rc = (ssize_t) used; + return rc; +} + +static int afu_release(struct inode *inode, struct file *file) +{ + struct ocxl_context *ctx = file->private_data; + int rc; + + pr_debug("%s for device %x\n", __func__, inode->i_rdev); + rc = ocxl_context_detach(ctx); + mutex_lock(&ctx->mapping_lock); + ctx->mapping = NULL; + mutex_unlock(&ctx->mapping_lock); + wake_up_all(&ctx->events_wq); + if (rc != -EBUSY) + ocxl_context_free(ctx); + return 0; +} + +static const struct file_operations ocxl_afu_fops = { + .owner = THIS_MODULE, + .open = afu_open, + .unlocked_ioctl = afu_ioctl, + .compat_ioctl = afu_compat_ioctl, + .mmap = afu_mmap, + .poll = afu_poll, + .read = afu_read, + .release = afu_release, +}; + +int ocxl_create_cdev(struct ocxl_afu *afu) +{ + int rc; + + cdev_init(&afu->cdev, &ocxl_afu_fops); + rc = cdev_add(&afu->cdev, afu->dev.devt, 1); + if (rc) { + dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc); + return rc; + } + return 0; +} + +void ocxl_destroy_cdev(struct ocxl_afu *afu) +{ + cdev_del(&afu->cdev); +} + +int ocxl_register_afu(struct ocxl_afu *afu) +{ + int minor; + + minor = allocate_afu_minor(afu); + if (minor < 0) + return minor; + afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor); + afu->dev.class = ocxl_class; + return device_register(&afu->dev); +} + +void ocxl_unregister_afu(struct ocxl_afu *afu) +{ + free_afu_minor(afu); +} + +static char *ocxl_devnode(struct device *dev, umode_t *mode) +{ + return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev)); +} + +int ocxl_file_init(void) +{ + int rc; + + mutex_init(&minors_idr_lock); + idr_init(&minors_idr); + + rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl"); + if (rc) { + pr_err("Unable to allocate ocxl major number: %d\n", rc); + return rc; + } + + ocxl_class = class_create(THIS_MODULE, "ocxl"); + if (IS_ERR(ocxl_class)) { + pr_err("Unable to create ocxl class\n"); + unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS); + return PTR_ERR(ocxl_class); + } + + ocxl_class->devnode = ocxl_devnode; + return 0; +} + +void ocxl_file_exit(void) +{ + class_destroy(ocxl_class); + unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS); + idr_destroy(&minors_idr); +} |