blob: d735937d975c8dca1b32f021e04ecb5fb47e703c [file] [log] [blame]
/*
* IOMMU helpers in MMU context.
*
* Copyright (C) 2015 IBM Corp. <aik@ozlabs.ru>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <linux/migrate.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <asm/mmu_context.h>
#include <asm/pte-walk.h>
static DEFINE_MUTEX(mem_list_mutex);
struct mm_iommu_table_group_mem_t {
struct list_head next;
struct rcu_head rcu;
unsigned long used;
atomic64_t mapped;
unsigned int pageshift;
u64 ua; /* userspace address */
u64 entries; /* number of entries in hpas[] */
u64 *hpas; /* vmalloc'ed */
};
static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
unsigned long npages, bool incr)
{
long ret = 0, locked, lock_limit;
if (!npages)
return 0;
down_write(&mm->mmap_sem);
if (incr) {
locked = mm->locked_vm + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
ret = -ENOMEM;
else
mm->locked_vm += npages;
} else {
if (WARN_ON_ONCE(npages > mm->locked_vm))
npages = mm->locked_vm;
mm->locked_vm -= npages;
}
pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
current ? current->pid : 0,
incr ? '+' : '-',
npages << PAGE_SHIFT,
mm->locked_vm << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK));
up_write(&mm->mmap_sem);
return ret;
}
bool mm_iommu_preregistered(struct mm_struct *mm)
{
return !list_empty(&mm->context.iommu_group_mem_list);
}
EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
/*
* Taken from alloc_migrate_target with changes to remove CMA allocations
*/
struct page *new_iommu_non_cma_page(struct page *page, unsigned long private,
int **resultp)
{
gfp_t gfp_mask = GFP_USER;
struct page *new_page;
if (PageCompound(page))
return NULL;
if (PageHighMem(page))
gfp_mask |= __GFP_HIGHMEM;
/*
* We don't want the allocation to force an OOM if possibe
*/
new_page = alloc_page(gfp_mask | __GFP_NORETRY | __GFP_NOWARN);
return new_page;
}
static int mm_iommu_move_page_from_cma(struct page *page)
{
int ret = 0;
LIST_HEAD(cma_migrate_pages);
/* Ignore huge pages for now */
if (PageCompound(page))
return -EBUSY;
lru_add_drain();
ret = isolate_lru_page(page);
if (ret)
return ret;
list_add(&page->lru, &cma_migrate_pages);
put_page(page); /* Drop the gup reference */
ret = migrate_pages(&cma_migrate_pages, new_iommu_non_cma_page,
NULL, 0, MIGRATE_SYNC, MR_CMA);
if (ret) {
if (!list_empty(&cma_migrate_pages))
putback_movable_pages(&cma_migrate_pages);
}
return 0;
}
long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries,
struct mm_iommu_table_group_mem_t **pmem)
{
struct mm_iommu_table_group_mem_t *mem;
long i, j, ret = 0, locked_entries = 0;
unsigned int pageshift;
unsigned long flags;
unsigned long cur_ua;
struct page *page = NULL;
mutex_lock(&mem_list_mutex);
list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list,
next) {
if ((mem->ua == ua) && (mem->entries == entries)) {
++mem->used;
*pmem = mem;
goto unlock_exit;
}
/* Overlap? */
if ((mem->ua < (ua + (entries << PAGE_SHIFT))) &&
(ua < (mem->ua +
(mem->entries << PAGE_SHIFT)))) {
ret = -EINVAL;
goto unlock_exit;
}
}
ret = mm_iommu_adjust_locked_vm(mm, entries, true);
if (ret)
goto unlock_exit;
locked_entries = entries;
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem) {
ret = -ENOMEM;
goto unlock_exit;
}
/*
* For a starting point for a maximum page size calculation
* we use @ua and @entries natural alignment to allow IOMMU pages
* smaller than huge pages but still bigger than PAGE_SIZE.
*/
mem->pageshift = __ffs(ua | (entries << PAGE_SHIFT));
mem->hpas = vzalloc(entries * sizeof(mem->hpas[0]));
if (!mem->hpas) {
kfree(mem);
ret = -ENOMEM;
goto unlock_exit;
}
for (i = 0; i < entries; ++i) {
cur_ua = ua + (i << PAGE_SHIFT);
if (1 != get_user_pages_fast(cur_ua,
1/* pages */, 1/* iswrite */, &page)) {
ret = -EFAULT;
for (j = 0; j < i; ++j)
put_page(pfn_to_page(mem->hpas[j] >>
PAGE_SHIFT));
vfree(mem->hpas);
kfree(mem);
goto unlock_exit;
}
/*
* If we get a page from the CMA zone, since we are going to
* be pinning these entries, we might as well move them out
* of the CMA zone if possible. NOTE: faulting in + migration
* can be expensive. Batching can be considered later
*/
if (is_migrate_cma_page(page)) {
if (mm_iommu_move_page_from_cma(page))
goto populate;
if (1 != get_user_pages_fast(cur_ua,
1/* pages */, 1/* iswrite */,
&page)) {
ret = -EFAULT;
for (j = 0; j < i; ++j)
put_page(pfn_to_page(mem->hpas[j] >>
PAGE_SHIFT));
vfree(mem->hpas);
kfree(mem);
goto unlock_exit;
}
}
populate:
pageshift = PAGE_SHIFT;
if (mem->pageshift > PAGE_SHIFT && PageCompound(page)) {
pte_t *pte;
struct page *head = compound_head(page);
unsigned int compshift = compound_order(head);
unsigned int pteshift;
local_irq_save(flags); /* disables as well */
pte = find_linux_pte(mm->pgd, cur_ua, NULL, &pteshift);
/* Double check it is still the same pinned page */
if (pte && pte_page(*pte) == head &&
pteshift == compshift + PAGE_SHIFT)
pageshift = max_t(unsigned int, pteshift,
PAGE_SHIFT);
local_irq_restore(flags);
}
mem->pageshift = min(mem->pageshift, pageshift);
mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT;
}
atomic64_set(&mem->mapped, 1);
mem->used = 1;
mem->ua = ua;
mem->entries = entries;
*pmem = mem;
list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list);
unlock_exit:
if (locked_entries && ret)
mm_iommu_adjust_locked_vm(mm, locked_entries, false);
mutex_unlock(&mem_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_get);
static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
{
long i;
struct page *page = NULL;
for (i = 0; i < mem->entries; ++i) {
if (!mem->hpas[i])
continue;
page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT);
if (!page)
continue;
put_page(page);
mem->hpas[i] = 0;
}
}
static void mm_iommu_do_free(struct mm_iommu_table_group_mem_t *mem)
{
mm_iommu_unpin(mem);
vfree(mem->hpas);
kfree(mem);
}
static void mm_iommu_free(struct rcu_head *head)
{
struct mm_iommu_table_group_mem_t *mem = container_of(head,
struct mm_iommu_table_group_mem_t, rcu);
mm_iommu_do_free(mem);
}
static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem)
{
list_del_rcu(&mem->next);
call_rcu(&mem->rcu, mm_iommu_free);
}
long mm_iommu_put(struct mm_struct *mm, struct mm_iommu_table_group_mem_t *mem)
{
long ret = 0;
mutex_lock(&mem_list_mutex);
if (mem->used == 0) {
ret = -ENOENT;
goto unlock_exit;
}
--mem->used;
/* There are still users, exit */
if (mem->used)
goto unlock_exit;
/* Are there still mappings? */
if (atomic_cmpxchg(&mem->mapped, 1, 0) != 1) {
++mem->used;
ret = -EBUSY;
goto unlock_exit;
}
/* @mapped became 0 so now mappings are disabled, release the region */
mm_iommu_release(mem);
mm_iommu_adjust_locked_vm(mm, mem->entries, false);
unlock_exit:
mutex_unlock(&mem_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_put);
struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
unsigned long ua, unsigned long size)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
if ((mem->ua <= ua) &&
(ua + size <= mem->ua +
(mem->entries << PAGE_SHIFT))) {
ret = mem;
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_lookup);
struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm,
unsigned long ua, unsigned long size)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
list_for_each_entry_lockless(mem, &mm->context.iommu_group_mem_list,
next) {
if ((mem->ua <= ua) &&
(ua + size <= mem->ua +
(mem->entries << PAGE_SHIFT))) {
ret = mem;
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_lookup_rm);
struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
unsigned long ua, unsigned long entries)
{
struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
if ((mem->ua == ua) && (mem->entries == entries)) {
ret = mem;
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_find);
long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
unsigned long ua, unsigned int pageshift, unsigned long *hpa)
{
const long entry = (ua - mem->ua) >> PAGE_SHIFT;
u64 *va = &mem->hpas[entry];
if (entry >= mem->entries)
return -EFAULT;
if (pageshift > mem->pageshift)
return -EFAULT;
*hpa = *va | (ua & ~PAGE_MASK);
return 0;
}
EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);
long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
unsigned long ua, unsigned int pageshift, unsigned long *hpa)
{
const long entry = (ua - mem->ua) >> PAGE_SHIFT;
void *va = &mem->hpas[entry];
unsigned long *pa;
if (entry >= mem->entries)
return -EFAULT;
if (pageshift > mem->pageshift)
return -EFAULT;
pa = (void *) vmalloc_to_phys(va);
if (!pa)
return -EFAULT;
*hpa = *pa | (ua & ~PAGE_MASK);
return 0;
}
EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa_rm);
long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem)
{
if (atomic64_inc_not_zero(&mem->mapped))
return 0;
/* Last mm_iommu_put() has been called, no more mappings allowed() */
return -ENXIO;
}
EXPORT_SYMBOL_GPL(mm_iommu_mapped_inc);
void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem)
{
atomic64_add_unless(&mem->mapped, -1, 1);
}
EXPORT_SYMBOL_GPL(mm_iommu_mapped_dec);
void mm_iommu_init(struct mm_struct *mm)
{
INIT_LIST_HEAD_RCU(&mm->context.iommu_group_mem_list);
}