linux/drivers/misc/ocxl/file.c
Alastair D'Silva 75ca758adb ocxl: Create a clear delineation between ocxl backend & frontend
The OCXL driver contains both frontend code for interacting with userspace,
as well as backend code for interacting with the hardware.

This patch separates the backend code from the frontend so that it can be
used by other device drivers that communicate via OpenCAPI.

Relocate dev, cdev & sysfs files to the frontend code to allow external
drivers to maintain their own devices.

Reference counting on the device in the backend is replaced with kref
counting.

Move file & sysfs layer initialisation from core.c (backend) to
pci.c (frontend).

Create an ocxl_function oriented interface for initing devices &
enumerating AFUs.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03 02:55:01 +10:00

599 lines
13 KiB
C

// 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 <asm/reg.h>
#include <asm/switch_to.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_file_info *find_file_info(dev_t devno)
{
struct ocxl_file_info *info;
/*
* 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
* info reference 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.
*/
info = idr_find(&minors_idr, MINOR(devno));
return info;
}
static int allocate_minor(struct ocxl_file_info *info)
{
int minor;
mutex_lock(&minors_idr_lock);
minor = idr_alloc(&minors_idr, info, 0, OCXL_NUM_MINORS, GFP_KERNEL);
mutex_unlock(&minors_idr_lock);
return minor;
}
static void free_minor(struct ocxl_file_info *info)
{
mutex_lock(&minors_idr_lock);
idr_remove(&minors_idr, MINOR(info->dev.devt));
mutex_unlock(&minors_idr_lock);
}
static int afu_open(struct inode *inode, struct file *file)
{
struct ocxl_file_info *info;
struct ocxl_context *ctx;
int rc;
pr_debug("%s for device %x\n", __func__, inode->i_rdev);
info = find_file_info(inode->i_rdev);
if (!info)
return -ENODEV;
ctx = ocxl_context_alloc();
if (!ctx)
return -ENOMEM;
rc = ocxl_context_init(ctx, info->afu, inode->i_mapping);
if (rc)
return rc;
file->private_data = ctx;
return 0;
}
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;
}
static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
struct ocxl_ioctl_metadata __user *uarg)
{
struct ocxl_ioctl_metadata arg;
memset(&arg, 0, sizeof(arg));
arg.version = 0;
arg.afu_version_major = ctx->afu->config.version_major;
arg.afu_version_minor = ctx->afu->config.version_minor;
arg.pasid = ctx->pasid;
arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
arg.global_mmio_size = ctx->afu->config.global_mmio_size;
if (copy_to_user(uarg, &arg, sizeof(arg)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_PPC64
static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
struct ocxl_ioctl_p9_wait __user *uarg)
{
struct ocxl_ioctl_p9_wait arg;
memset(&arg, 0, sizeof(arg));
if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
enum ocxl_context_status status;
// Locks both status & tidr
mutex_lock(&ctx->status_mutex);
if (!ctx->tidr) {
if (set_thread_tidr(current)) {
mutex_unlock(&ctx->status_mutex);
return -ENOENT;
}
ctx->tidr = current->thread.tidr;
}
status = ctx->status;
mutex_unlock(&ctx->status_mutex);
if (status == ATTACHED) {
int rc = ocxl_link_update_pe(ctx->afu->fn->link,
ctx->pasid, ctx->tidr);
if (rc)
return rc;
}
arg.thread_id = ctx->tidr;
} else
return -ENOENT;
if (copy_to_user(uarg, &arg, sizeof(arg)))
return -EFAULT;
return 0;
}
#endif
static long afu_ioctl_get_features(struct ocxl_context *ctx,
struct ocxl_ioctl_features __user *uarg)
{
struct ocxl_ioctl_features arg;
memset(&arg, 0, sizeof(arg));
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_P9_TIDR))
arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
#endif
if (copy_to_user(uarg, &arg, sizeof(arg)))
return -EFAULT;
return 0;
}
#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" : \
x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" : \
x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
"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;
bool closed;
pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
CMD_STR(cmd));
mutex_lock(&ctx->status_mutex);
closed = (ctx->status == CLOSED);
mutex_unlock(&ctx->status_mutex);
if (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;
case OCXL_IOCTL_GET_METADATA:
rc = afu_ioctl_get_metadata(ctx,
(struct ocxl_ioctl_metadata __user *) args);
break;
#ifdef CONFIG_PPC64
case OCXL_IOCTL_ENABLE_P9_WAIT:
rc = afu_ioctl_enable_p9_wait(ctx,
(struct ocxl_ioctl_p9_wait __user *) args);
break;
#endif
case OCXL_IOCTL_GET_FEATURES:
rc = afu_ioctl_get_features(ctx,
(struct ocxl_ioctl_features __user *) args);
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,
};
// Free the info struct
static void info_release(struct device *dev)
{
struct ocxl_file_info *info = container_of(dev, struct ocxl_file_info, dev);
free_minor(info);
ocxl_afu_put(info->afu);
kfree(info);
}
static int ocxl_file_make_visible(struct ocxl_file_info *info)
{
int rc;
cdev_init(&info->cdev, &ocxl_afu_fops);
rc = cdev_add(&info->cdev, info->dev.devt, 1);
if (rc) {
dev_err(&info->dev, "Unable to add afu char device: %d\n", rc);
return rc;
}
return 0;
}
static void ocxl_file_make_invisible(struct ocxl_file_info *info)
{
cdev_del(&info->cdev);
}
int ocxl_file_register_afu(struct ocxl_afu *afu)
{
int minor;
int rc;
struct ocxl_file_info *info;
struct ocxl_fn *fn = afu->fn;
struct pci_dev *pci_dev = to_pci_dev(fn->dev.parent);
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (info == NULL)
return -ENOMEM;
minor = allocate_minor(info);
if (minor < 0) {
kfree(info);
return minor;
}
info->dev.parent = &fn->dev;
info->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
info->dev.class = ocxl_class;
info->dev.release = info_release;
info->afu = afu;
ocxl_afu_get(afu);
rc = dev_set_name(&info->dev, "%s.%s.%hhu",
afu->config.name, dev_name(&pci_dev->dev), afu->config.idx);
if (rc)
goto err_put;
rc = device_register(&info->dev);
if (rc)
goto err_put;
rc = ocxl_sysfs_register_afu(info);
if (rc)
goto err_unregister;
rc = ocxl_file_make_visible(info);
if (rc)
goto err_unregister;
ocxl_afu_set_private(afu, info);
return 0;
err_unregister:
ocxl_sysfs_unregister_afu(info); // safe to call even if register failed
device_unregister(&info->dev);
err_put:
ocxl_afu_put(afu);
free_minor(info);
kfree(info);
return rc;
}
void ocxl_file_unregister_afu(struct ocxl_afu *afu)
{
struct ocxl_file_info *info = ocxl_afu_get_private(afu);
if (!info)
return;
ocxl_file_make_invisible(info);
ocxl_sysfs_unregister_afu(info);
device_unregister(&info->dev);
}
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);
}