linuxdebug/drivers/misc/cxl/api.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2014 IBM Corp.
*/
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <misc/cxl.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <linux/sched/mm.h>
#include <linux/mmu_context.h>
#include <linux/irqdomain.h>
#include "cxl.h"
/*
* Since we want to track memory mappings to be able to force-unmap
* when the AFU is no longer reachable, we need an inode. For devices
* opened through the cxl user API, this is not a problem, but a
* userland process can also get a cxl fd through the cxl_get_fd()
* API, which is used by the cxlflash driver.
*
* Therefore we implement our own simple pseudo-filesystem and inode
* allocator. We don't use the anonymous inode, as we need the
* meta-data associated with it (address_space) and it is shared by
* other drivers/processes, so it could lead to cxl unmapping VMAs
* from random processes.
*/
#define CXL_PSEUDO_FS_MAGIC 0x1697697f
static int cxl_fs_cnt;
static struct vfsmount *cxl_vfs_mount;
static int cxl_fs_init_fs_context(struct fs_context *fc)
{
return init_pseudo(fc, CXL_PSEUDO_FS_MAGIC) ? 0 : -ENOMEM;
}
static struct file_system_type cxl_fs_type = {
.name = "cxl",
.owner = THIS_MODULE,
.init_fs_context = cxl_fs_init_fs_context,
.kill_sb = kill_anon_super,
};
void cxl_release_mapping(struct cxl_context *ctx)
{
if (ctx->kernelapi && ctx->mapping)
simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
}
static struct file *cxl_getfile(const char *name,
const struct file_operations *fops,
void *priv, int flags)
{
struct file *file;
struct inode *inode;
int rc;
/* strongly inspired by anon_inode_getfile() */
if (fops->owner && !try_module_get(fops->owner))
return ERR_PTR(-ENOENT);
rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
if (rc < 0) {
pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
file = ERR_PTR(rc);
goto err_module;
}
inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
if (IS_ERR(inode)) {
file = ERR_CAST(inode);
goto err_fs;
}
file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
flags & (O_ACCMODE | O_NONBLOCK), fops);
if (IS_ERR(file))
goto err_inode;
file->private_data = priv;
return file;
err_inode:
iput(inode);
err_fs:
simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
err_module:
module_put(fops->owner);
return file;
}
struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
{
struct cxl_afu *afu;
struct cxl_context *ctx;
int rc;
afu = cxl_pci_to_afu(dev);
if (IS_ERR(afu))
return ERR_CAST(afu);
ctx = cxl_context_alloc();
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->kernelapi = true;
/* Make it a slave context. We can promote it later? */
rc = cxl_context_init(ctx, afu, false);
if (rc)
goto err_ctx;
return ctx;
err_ctx:
kfree(ctx);
return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(cxl_dev_context_init);
struct cxl_context *cxl_get_context(struct pci_dev *dev)
{
return dev->dev.archdata.cxl_ctx;
}
EXPORT_SYMBOL_GPL(cxl_get_context);
int cxl_release_context(struct cxl_context *ctx)
{
if (ctx->status >= STARTED)
return -EBUSY;
cxl_context_free(ctx);
return 0;
}
EXPORT_SYMBOL_GPL(cxl_release_context);
static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
{
__u16 range;
int r;
for (r = 0; r < CXL_IRQ_RANGES; r++) {
range = ctx->irqs.range[r];
if (num < range) {
return ctx->irqs.offset[r] + num;
}
num -= range;
}
return 0;
}
int cxl_set_priv(struct cxl_context *ctx, void *priv)
{
if (!ctx)
return -EINVAL;
ctx->priv = priv;
return 0;
}
EXPORT_SYMBOL_GPL(cxl_set_priv);
void *cxl_get_priv(struct cxl_context *ctx)
{
if (!ctx)
return ERR_PTR(-EINVAL);
return ctx->priv;
}
EXPORT_SYMBOL_GPL(cxl_get_priv);
int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
{
int res;
irq_hw_number_t hwirq;
if (num == 0)
num = ctx->afu->pp_irqs;
res = afu_allocate_irqs(ctx, num);
if (res)
return res;
if (!cpu_has_feature(CPU_FTR_HVMODE)) {
/* In a guest, the PSL interrupt is not multiplexed. It was
* allocated above, and we need to set its handler
*/
hwirq = cxl_find_afu_irq(ctx, 0);
if (hwirq)
cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
}
if (ctx->status == STARTED) {
if (cxl_ops->update_ivtes)
cxl_ops->update_ivtes(ctx);
else WARN(1, "BUG: cxl_allocate_afu_irqs must be called prior to starting the context on this platform\n");
}
return res;
}
EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
void cxl_free_afu_irqs(struct cxl_context *ctx)
{
irq_hw_number_t hwirq;
unsigned int virq;
if (!cpu_has_feature(CPU_FTR_HVMODE)) {
hwirq = cxl_find_afu_irq(ctx, 0);
if (hwirq) {
virq = irq_find_mapping(NULL, hwirq);
if (virq)
cxl_unmap_irq(virq, ctx);
}
}
afu_irq_name_free(ctx);
cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
}
EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
int cxl_map_afu_irq(struct cxl_context *ctx, int num,
irq_handler_t handler, void *cookie, char *name)
{
irq_hw_number_t hwirq;
/*
* Find interrupt we are to register.
*/
hwirq = cxl_find_afu_irq(ctx, num);
if (!hwirq)
return -ENOENT;
return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
}
EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
{
irq_hw_number_t hwirq;
unsigned int virq;
hwirq = cxl_find_afu_irq(ctx, num);
if (!hwirq)
return;
virq = irq_find_mapping(NULL, hwirq);
if (virq)
cxl_unmap_irq(virq, cookie);
}
EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
/*
* Start a context
* Code here similar to afu_ioctl_start_work().
*/
int cxl_start_context(struct cxl_context *ctx, u64 wed,
struct task_struct *task)
{
int rc = 0;
bool kernel = true;
pr_devel("%s: pe: %i\n", __func__, ctx->pe);
mutex_lock(&ctx->status_mutex);
if (ctx->status == STARTED)
goto out; /* already started */
/*
* 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)
goto out;
if (task) {
ctx->pid = get_task_pid(task, PIDTYPE_PID);
kernel = false;
/* 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();
/* See the comment in afu_ioctl_start_work() */
smp_mb();
if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
put_pid(ctx->pid);
ctx->pid = NULL;
cxl_adapter_context_put(ctx->afu->adapter);
cxl_ctx_put();
if (task) {
cxl_context_mm_count_put(ctx);
if (ctx->mm)
mm_context_remove_copro(ctx->mm);
}
goto out;
}
ctx->status = STARTED;
out:
mutex_unlock(&ctx->status_mutex);
return rc;
}
EXPORT_SYMBOL_GPL(cxl_start_context);
int cxl_process_element(struct cxl_context *ctx)
{
return ctx->external_pe;
}
EXPORT_SYMBOL_GPL(cxl_process_element);
/* Stop a context. Returns 0 on success, otherwise -Errno */
int cxl_stop_context(struct cxl_context *ctx)
{
return __detach_context(ctx);
}
EXPORT_SYMBOL_GPL(cxl_stop_context);
void cxl_set_master(struct cxl_context *ctx)
{
ctx->master = true;
}
EXPORT_SYMBOL_GPL(cxl_set_master);
/* wrappers around afu_* file ops which are EXPORTED */
int cxl_fd_open(struct inode *inode, struct file *file)
{
return afu_open(inode, file);
}
EXPORT_SYMBOL_GPL(cxl_fd_open);
int cxl_fd_release(struct inode *inode, struct file *file)
{
return afu_release(inode, file);
}
EXPORT_SYMBOL_GPL(cxl_fd_release);
long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return afu_ioctl(file, cmd, arg);
}
EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
{
return afu_mmap(file, vm);
}
EXPORT_SYMBOL_GPL(cxl_fd_mmap);
__poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
{
return afu_poll(file, poll);
}
EXPORT_SYMBOL_GPL(cxl_fd_poll);
ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
loff_t *off)
{
return afu_read(file, buf, count, off);
}
EXPORT_SYMBOL_GPL(cxl_fd_read);
#define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
/* Get a struct file and fd for a context and attach the ops */
struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
int *fd)
{
struct file *file;
int rc, flags, fdtmp;
char *name = NULL;
/* only allow one per context */
if (ctx->mapping)
return ERR_PTR(-EEXIST);
flags = O_RDWR | O_CLOEXEC;
/* This code is similar to anon_inode_getfd() */
rc = get_unused_fd_flags(flags);
if (rc < 0)
return ERR_PTR(rc);
fdtmp = rc;
/*
* Patch the file ops. Needs to be careful that this is rentrant safe.
*/
if (fops) {
PATCH_FOPS(open);
PATCH_FOPS(poll);
PATCH_FOPS(read);
PATCH_FOPS(release);
PATCH_FOPS(unlocked_ioctl);
PATCH_FOPS(compat_ioctl);
PATCH_FOPS(mmap);
} else /* use default ops */
fops = (struct file_operations *)&afu_fops;
name = kasprintf(GFP_KERNEL, "cxl:%d", ctx->pe);
file = cxl_getfile(name, fops, ctx, flags);
kfree(name);
if (IS_ERR(file))
goto err_fd;
cxl_context_set_mapping(ctx, file->f_mapping);
*fd = fdtmp;
return file;
err_fd:
put_unused_fd(fdtmp);
return NULL;
}
EXPORT_SYMBOL_GPL(cxl_get_fd);
struct cxl_context *cxl_fops_get_context(struct file *file)
{
return file->private_data;
}
EXPORT_SYMBOL_GPL(cxl_fops_get_context);
void cxl_set_driver_ops(struct cxl_context *ctx,
struct cxl_afu_driver_ops *ops)
{
WARN_ON(!ops->fetch_event || !ops->event_delivered);
atomic_set(&ctx->afu_driver_events, 0);
ctx->afu_driver_ops = ops;
}
EXPORT_SYMBOL_GPL(cxl_set_driver_ops);
void cxl_context_events_pending(struct cxl_context *ctx,
unsigned int new_events)
{
atomic_add(new_events, &ctx->afu_driver_events);
wake_up_all(&ctx->wq);
}
EXPORT_SYMBOL_GPL(cxl_context_events_pending);
int cxl_start_work(struct cxl_context *ctx,
struct cxl_ioctl_start_work *work)
{
int rc;
/* code taken from afu_ioctl_start_work */
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)) {
return -EINVAL;
}
rc = afu_register_irqs(ctx, work->num_interrupts);
if (rc)
return rc;
rc = cxl_start_context(ctx, work->work_element_descriptor, current);
if (rc < 0) {
afu_release_irqs(ctx, ctx);
return rc;
}
return 0;
}
EXPORT_SYMBOL_GPL(cxl_start_work);
void __iomem *cxl_psa_map(struct cxl_context *ctx)
{
if (ctx->status != STARTED)
return NULL;
pr_devel("%s: psn_phys%llx size:%llx\n",
__func__, ctx->psn_phys, ctx->psn_size);
return ioremap(ctx->psn_phys, ctx->psn_size);
}
EXPORT_SYMBOL_GPL(cxl_psa_map);
void cxl_psa_unmap(void __iomem *addr)
{
iounmap(addr);
}
EXPORT_SYMBOL_GPL(cxl_psa_unmap);
int cxl_afu_reset(struct cxl_context *ctx)
{
struct cxl_afu *afu = ctx->afu;
int rc;
rc = cxl_ops->afu_reset(afu);
if (rc)
return rc;
return cxl_ops->afu_check_and_enable(afu);
}
EXPORT_SYMBOL_GPL(cxl_afu_reset);
void cxl_perst_reloads_same_image(struct cxl_afu *afu,
bool perst_reloads_same_image)
{
afu->adapter->perst_same_image = perst_reloads_same_image;
}
EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
{
struct cxl_afu *afu = cxl_pci_to_afu(dev);
if (IS_ERR(afu))
return -ENODEV;
return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
}
EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);