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drm/amdkfd: remove dead kernel-allocated signal page code

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With the KFD_MMAP_TYPE_EVENTS mmap path gone, a kernel-allocated signal
page can no longer be exposed to user space, so allocate_signal_page()
and the related bookkeeping are dead code. The only remaining way to set
up a signal page is kfd_kmap_event_page()/kfd_event_page_set(), where
user space allocates the events page as a BO and passes it via the
event_page_offset of the create event IOCTL.

Remove allocate_signal_page() and require the signal page to be provided
by user space. Drop the now unused kfd_signal_page user mapping
bookkeeping (user_address/need_to_free_pages) and
kfd_event::user_signal_address.

Signed-off-by: Yongqiang Sun <Yongqiang.Sun@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Yongqiang Sun 2026-06-11 15:42:34 -04:00 committed by Alex Deucher
parent 0cfc1e9faf
commit b4f5837f74
2 changed files with 10 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
drivers/gpu/drm/amd/amdkfd/kfd_events.c
View File

@ -55,8 +55,6 @@ struct kfd_event_waiter {
*/
struct kfd_signal_page {
uint64_t *kernel_address;
uint64_t __user *user_address;
bool need_to_free_pages;
};
static uint64_t *page_slots(struct kfd_signal_page *page)
@ -64,49 +62,19 @@ static uint64_t *page_slots(struct kfd_signal_page *page)
return page->kernel_address;
}
static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
{
void *backing_store;
struct kfd_signal_page *page;
page = kzalloc_obj(*page);
if (!page)
return NULL;
backing_store = (void *) __get_free_pages(GFP_KERNEL,
get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
if (!backing_store)
goto fail_alloc_signal_store;
/* Initialize all events to unsignaled */
memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
KFD_SIGNAL_EVENT_LIMIT * 8);
page->kernel_address = backing_store;
page->need_to_free_pages = true;
pr_debug("Allocated new event signal page at %p, for process %p\n",
page, p);
return page;
fail_alloc_signal_store:
kfree(page);
return NULL;
}
static int allocate_event_notification_slot(struct kfd_process *p,
struct kfd_event *ev,
const int *restore_id)
{
int id;
if (!p->signal_page) {
p->signal_page = allocate_signal_page(p);
if (!p->signal_page)
return -ENOMEM;
/* Oldest user mode expects 256 event slots */
p->signal_mapped_size = 256*8;
}
/*
* The signal page is allocated in user mode and mapped to the kernel
* via the event_page_offset of the create event IOCTL. Without it no
* signal events can be created.
*/
if (!p->signal_page)
return -ENOMEM;
if (restore_id) {
id = idr_alloc(&p->event_idr, ev, *restore_id, *restore_id + 1,
@ -212,10 +180,8 @@ static int create_signal_event(struct file *devkfd, struct kfd_process *p,
p->signal_event_count++;
ev->user_signal_address = &p->signal_page->user_address[ev->event_id];
pr_debug("Signal event number %zu created with id %d, address %p\n",
p->signal_event_count, ev->event_id,
ev->user_signal_address);
pr_debug("Signal event number %zu created with id %d\n",
p->signal_event_count, ev->event_id);
return 0;
}
@ -303,12 +269,7 @@ static void shutdown_signal_page(struct kfd_process *p)
{
struct kfd_signal_page *page = p->signal_page;
if (page) {
if (page->need_to_free_pages)
free_pages((unsigned long)page->kernel_address,
get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
kfree(page);
}
kfree(page);
}
void kfd_event_free_process(struct kfd_process *p)

3
drivers/gpu/drm/amd/amdkfd/kfd_events.h
View File

@ -63,9 +63,6 @@ struct kfd_event {
spinlock_t lock;
wait_queue_head_t wq; /* List of event waiters. */
/* Only for signal events. */
uint64_t __user *user_signal_address;
/* type specific data */
union {
struct kfd_hsa_memory_exception_data memory_exception_data;