--- /dev/null
+/*
+ * 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.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+#include <linux/vmalloc.h>
+#include <linux/mutex.h>
+#include <asm/mmu_context.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;
+ 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->pid,
+ incr ? '+' : '-',
+ npages << PAGE_SHIFT,
+ mm->locked_vm << PAGE_SHIFT,
+ rlimit(RLIMIT_MEMLOCK));
+ up_write(&mm->mmap_sem);
+
+ return ret;
+}
+
+bool mm_iommu_preregistered(void)
+{
+ if (!current || !current->mm)
+ return false;
+
+ return !list_empty(¤t->mm->context.iommu_group_mem_list);
+}
+EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
+
+long mm_iommu_get(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;
+ struct page *page = NULL;
+
+ if (!current || !current->mm)
+ return -ESRCH; /* process exited */
+
+ mutex_lock(&mem_list_mutex);
+
+ list_for_each_entry_rcu(mem, ¤t->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(current->mm, entries, true);
+ if (ret)
+ goto unlock_exit;
+
+ locked_entries = entries;
+
+ mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+ if (!mem) {
+ ret = -ENOMEM;
+ goto unlock_exit;
+ }
+
+ mem->hpas = vzalloc(entries * sizeof(mem->hpas[0]));
+ if (!mem->hpas) {
+ kfree(mem);
+ ret = -ENOMEM;
+ goto unlock_exit;
+ }
+
+ for (i = 0; i < entries; ++i) {
+ if (1 != get_user_pages_fast(ua + (i << PAGE_SHIFT),
+ 1/* pages */, 1/* iswrite */, &page)) {
+ for (j = 0; j < i; ++j)
+ put_page(pfn_to_page(
+ mem->hpas[j] >> PAGE_SHIFT));
+ vfree(mem->hpas);
+ kfree(mem);
+ ret = -EFAULT;
+ goto unlock_exit;
+ }
+
+ 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, ¤t->mm->context.iommu_group_mem_list);
+
+unlock_exit:
+ if (locked_entries && ret)
+ mm_iommu_adjust_locked_vm(current->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);
+ mm_iommu_adjust_locked_vm(current->mm, mem->entries, false);
+ call_rcu(&mem->rcu, mm_iommu_free);
+}
+
+long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
+{
+ long ret = 0;
+
+ if (!current || !current->mm)
+ return -ESRCH; /* process exited */
+
+ 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);
+
+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(unsigned long ua,
+ unsigned long size)
+{
+ struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
+
+ list_for_each_entry_rcu(mem,
+ ¤t->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_find(unsigned long ua,
+ unsigned long entries)
+{
+ struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
+
+ list_for_each_entry_rcu(mem,
+ ¤t->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 long *hpa)
+{
+ const long entry = (ua - mem->ua) >> PAGE_SHIFT;
+ u64 *va = &mem->hpas[entry];
+
+ if (entry >= mem->entries)
+ return -EFAULT;
+
+ *hpa = *va | (ua & ~PAGE_MASK);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);
+
+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(mm_context_t *ctx)
+{
+ INIT_LIST_HEAD_RCU(&ctx->iommu_group_mem_list);
+}
+
+void mm_iommu_cleanup(mm_context_t *ctx)
+{
+ struct mm_iommu_table_group_mem_t *mem, *tmp;
+
+ list_for_each_entry_safe(mem, tmp, &ctx->iommu_group_mem_list, next) {
+ list_del_rcu(&mem->next);
+ mm_iommu_do_free(mem);
+ }
+}
projects / karo-tx-linux.git / commitdiff