blob: 337462e1569fee2628fc6126c29c3acc9cc904ae [file] [log] [blame]
// 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);
return -EFAULT;
}
}
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 = EPOLLIN | EPOLLRDNORM;
else if (closed)
mask = EPOLLERR;
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;
ssize_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 = 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);
}