98 lines
2.3 KiB
C
98 lines
2.3 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-only
|
||
|
|
|
||
|
|
#include <linux/pagemap.h>
|
||
|
|
#include <linux/xarray.h>
|
||
|
|
#include <linux/slab.h>
|
||
|
|
#include <linux/swap.h>
|
||
|
|
#include <linux/swapops.h>
|
||
|
|
#include <asm/mte.h>
|
||
|
|
|
||
|
|
static DEFINE_XARRAY(mte_pages);
|
||
|
|
|
||
|
|
void *mte_allocate_tag_storage(void)
|
||
|
|
{
|
||
|
|
/* tags granule is 16 bytes, 2 tags stored per byte */
|
||
|
|
return kmalloc(PAGE_SIZE / 16 / 2, GFP_KERNEL);
|
||
|
|
}
|
||
|
|
|
||
|
|
void mte_free_tag_storage(char *storage)
|
||
|
|
{
|
||
|
|
kfree(storage);
|
||
|
|
}
|
||
|
|
|
||
|
|
int mte_save_tags(struct page *page)
|
||
|
|
{
|
||
|
|
void *tag_storage, *ret;
|
||
|
|
|
||
|
|
if (!test_bit(PG_mte_tagged, &page->flags))
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
tag_storage = mte_allocate_tag_storage();
|
||
|
|
if (!tag_storage)
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
mte_save_page_tags(page_address(page), tag_storage);
|
||
|
|
|
||
|
|
/* page_private contains the swap entry.val set in do_swap_page */
|
||
|
|
ret = xa_store(&mte_pages, page_private(page), tag_storage, GFP_KERNEL);
|
||
|
|
if (WARN(xa_is_err(ret), "Failed to store MTE tags")) {
|
||
|
|
mte_free_tag_storage(tag_storage);
|
||
|
|
return xa_err(ret);
|
||
|
|
} else if (ret) {
|
||
|
|
/* Entry is being replaced, free the old entry */
|
||
|
|
mte_free_tag_storage(ret);
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
bool mte_restore_tags(swp_entry_t entry, struct page *page)
|
||
|
|
{
|
||
|
|
void *tags = xa_load(&mte_pages, entry.val);
|
||
|
|
|
||
|
|
if (!tags)
|
||
|
|
return false;
|
||
|
|
|
||
|
|
page_kasan_tag_reset(page);
|
||
|
|
/*
|
||
|
|
* We need smp_wmb() in between setting the flags and clearing the
|
||
|
|
* tags because if another thread reads page->flags and builds a
|
||
|
|
* tagged address out of it, there is an actual dependency to the
|
||
|
|
* memory access, but on the current thread we do not guarantee that
|
||
|
|
* the new page->flags are visible before the tags were updated.
|
||
|
|
*/
|
||
|
|
smp_wmb();
|
||
|
|
/*
|
||
|
|
* Test PG_mte_tagged again in case it was racing with another
|
||
|
|
* set_pte_at().
|
||
|
|
*/
|
||
|
|
if (!test_and_set_bit(PG_mte_tagged, &page->flags))
|
||
|
|
mte_restore_page_tags(page_address(page), tags);
|
||
|
|
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
void mte_invalidate_tags(int type, pgoff_t offset)
|
||
|
|
{
|
||
|
|
swp_entry_t entry = swp_entry(type, offset);
|
||
|
|
void *tags = xa_erase(&mte_pages, entry.val);
|
||
|
|
|
||
|
|
mte_free_tag_storage(tags);
|
||
|
|
}
|
||
|
|
|
||
|
|
void mte_invalidate_tags_area(int type)
|
||
|
|
{
|
||
|
|
swp_entry_t entry = swp_entry(type, 0);
|
||
|
|
swp_entry_t last_entry = swp_entry(type + 1, 0);
|
||
|
|
void *tags;
|
||
|
|
|
||
|
|
XA_STATE(xa_state, &mte_pages, entry.val);
|
||
|
|
|
||
|
|
xa_lock(&mte_pages);
|
||
|
|
xas_for_each(&xa_state, tags, last_entry.val - 1) {
|
||
|
|
__xa_erase(&mte_pages, xa_state.xa_index);
|
||
|
|
mte_free_tag_storage(tags);
|
||
|
|
}
|
||
|
|
xa_unlock(&mte_pages);
|
||
|
|
}
|