ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/mm/mmu_notifier.c b/marvell/linux/mm/mmu_notifier.c
new file mode 100644
index 0000000..9a889e4
--- /dev/null
+++ b/marvell/linux/mm/mmu_notifier.c
@@ -0,0 +1,546 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/mm/mmu_notifier.c
+ *
+ * Copyright (C) 2008 Qumranet, Inc.
+ * Copyright (C) 2008 SGI
+ * Christoph Lameter <cl@linux.com>
+ */
+
+#include <linux/rculist.h>
+#include <linux/mmu_notifier.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/err.h>
+#include <linux/srcu.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.h>
+
+/* global SRCU for all MMs */
+DEFINE_STATIC_SRCU(srcu);
+
+#ifdef CONFIG_LOCKDEP
+struct lockdep_map __mmu_notifier_invalidate_range_start_map = {
+ .name = "mmu_notifier_invalidate_range_start"
+};
+#endif
+
+/*
+ * This function can't run concurrently against mmu_notifier_register
+ * because mm->mm_users > 0 during mmu_notifier_register and exit_mmap
+ * runs with mm_users == 0. Other tasks may still invoke mmu notifiers
+ * in parallel despite there being no task using this mm any more,
+ * through the vmas outside of the exit_mmap context, such as with
+ * vmtruncate. This serializes against mmu_notifier_unregister with
+ * the mmu_notifier_mm->lock in addition to SRCU and it serializes
+ * against the other mmu notifiers with SRCU. struct mmu_notifier_mm
+ * can't go away from under us as exit_mmap holds an mm_count pin
+ * itself.
+ */
+void __mmu_notifier_release(struct mm_struct *mm)
+{
+ struct mmu_notifier *mn;
+ int id;
+
+ /*
+ * SRCU here will block mmu_notifier_unregister until
+ * ->release returns.
+ */
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist)
+ /*
+ * If ->release runs before mmu_notifier_unregister it must be
+ * handled, as it's the only way for the driver to flush all
+ * existing sptes and stop the driver from establishing any more
+ * sptes before all the pages in the mm are freed.
+ */
+ if (mn->ops->release)
+ mn->ops->release(mn, mm);
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ while (unlikely(!hlist_empty(&mm->mmu_notifier_mm->list))) {
+ mn = hlist_entry(mm->mmu_notifier_mm->list.first,
+ struct mmu_notifier,
+ hlist);
+ /*
+ * We arrived before mmu_notifier_unregister so
+ * mmu_notifier_unregister will do nothing other than to wait
+ * for ->release to finish and for mmu_notifier_unregister to
+ * return.
+ */
+ hlist_del_init_rcu(&mn->hlist);
+ }
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ srcu_read_unlock(&srcu, id);
+
+ /*
+ * synchronize_srcu here prevents mmu_notifier_release from returning to
+ * exit_mmap (which would proceed with freeing all pages in the mm)
+ * until the ->release method returns, if it was invoked by
+ * mmu_notifier_unregister.
+ *
+ * The mmu_notifier_mm can't go away from under us because one mm_count
+ * is held by exit_mmap.
+ */
+ synchronize_srcu(&srcu);
+}
+
+/*
+ * If no young bitflag is supported by the hardware, ->clear_flush_young can
+ * unmap the address and return 1 or 0 depending if the mapping previously
+ * existed or not.
+ */
+int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct mmu_notifier *mn;
+ int young = 0, id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->clear_flush_young)
+ young |= mn->ops->clear_flush_young(mn, mm, start, end);
+ }
+ srcu_read_unlock(&srcu, id);
+
+ return young;
+}
+
+int __mmu_notifier_clear_young(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct mmu_notifier *mn;
+ int young = 0, id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->clear_young)
+ young |= mn->ops->clear_young(mn, mm, start, end);
+ }
+ srcu_read_unlock(&srcu, id);
+
+ return young;
+}
+
+int __mmu_notifier_test_young(struct mm_struct *mm,
+ unsigned long address)
+{
+ struct mmu_notifier *mn;
+ int young = 0, id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->test_young) {
+ young = mn->ops->test_young(mn, mm, address);
+ if (young)
+ break;
+ }
+ }
+ srcu_read_unlock(&srcu, id);
+
+ return young;
+}
+
+void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address,
+ pte_t pte)
+{
+ struct mmu_notifier *mn;
+ int id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->change_pte)
+ mn->ops->change_pte(mn, mm, address, pte);
+ }
+ srcu_read_unlock(&srcu, id);
+}
+
+int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
+{
+ struct mmu_notifier *mn;
+ int ret = 0;
+ int id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &range->mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->invalidate_range_start) {
+ int _ret;
+
+ if (!mmu_notifier_range_blockable(range))
+ non_block_start();
+ _ret = mn->ops->invalidate_range_start(mn, range);
+ if (!mmu_notifier_range_blockable(range))
+ non_block_end();
+ if (_ret) {
+ pr_info("%pS callback failed with %d in %sblockable context.\n",
+ mn->ops->invalidate_range_start, _ret,
+ !mmu_notifier_range_blockable(range) ? "non-" : "");
+ WARN_ON(mmu_notifier_range_blockable(range) ||
+ _ret != -EAGAIN);
+ ret = _ret;
+ }
+ }
+ }
+ srcu_read_unlock(&srcu, id);
+
+ return ret;
+}
+
+void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range,
+ bool only_end)
+{
+ struct mmu_notifier *mn;
+ int id;
+
+ lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &range->mm->mmu_notifier_mm->list, hlist) {
+ /*
+ * Call invalidate_range here too to avoid the need for the
+ * subsystem of having to register an invalidate_range_end
+ * call-back when there is invalidate_range already. Usually a
+ * subsystem registers either invalidate_range_start()/end() or
+ * invalidate_range(), so this will be no additional overhead
+ * (besides the pointer check).
+ *
+ * We skip call to invalidate_range() if we know it is safe ie
+ * call site use mmu_notifier_invalidate_range_only_end() which
+ * is safe to do when we know that a call to invalidate_range()
+ * already happen under page table lock.
+ */
+ if (!only_end && mn->ops->invalidate_range)
+ mn->ops->invalidate_range(mn, range->mm,
+ range->start,
+ range->end);
+ if (mn->ops->invalidate_range_end) {
+ if (!mmu_notifier_range_blockable(range))
+ non_block_start();
+ mn->ops->invalidate_range_end(mn, range);
+ if (!mmu_notifier_range_blockable(range))
+ non_block_end();
+ }
+ }
+ srcu_read_unlock(&srcu, id);
+ lock_map_release(&__mmu_notifier_invalidate_range_start_map);
+}
+
+void __mmu_notifier_invalidate_range(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct mmu_notifier *mn;
+ int id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->invalidate_range)
+ mn->ops->invalidate_range(mn, mm, start, end);
+ }
+ srcu_read_unlock(&srcu, id);
+}
+
+/*
+ * Same as mmu_notifier_register but here the caller must hold the
+ * mmap_sem in write mode.
+ */
+int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ struct mmu_notifier_mm *mmu_notifier_mm = NULL;
+ int ret;
+
+ lockdep_assert_held_write(&mm->mmap_sem);
+ BUG_ON(atomic_read(&mm->mm_users) <= 0);
+
+ if (IS_ENABLED(CONFIG_LOCKDEP)) {
+ fs_reclaim_acquire(GFP_KERNEL);
+ lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
+ lock_map_release(&__mmu_notifier_invalidate_range_start_map);
+ fs_reclaim_release(GFP_KERNEL);
+ }
+
+ mn->mm = mm;
+ mn->users = 1;
+
+ if (!mm->mmu_notifier_mm) {
+ /*
+ * kmalloc cannot be called under mm_take_all_locks(), but we
+ * know that mm->mmu_notifier_mm can't change while we hold
+ * the write side of the mmap_sem.
+ */
+ mmu_notifier_mm =
+ kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL);
+ if (!mmu_notifier_mm)
+ return -ENOMEM;
+
+ INIT_HLIST_HEAD(&mmu_notifier_mm->list);
+ spin_lock_init(&mmu_notifier_mm->lock);
+ }
+
+ ret = mm_take_all_locks(mm);
+ if (unlikely(ret))
+ goto out_clean;
+
+ /* Pairs with the mmdrop in mmu_notifier_unregister_* */
+ mmgrab(mm);
+
+ /*
+ * Serialize the update against mmu_notifier_unregister. A
+ * side note: mmu_notifier_release can't run concurrently with
+ * us because we hold the mm_users pin (either implicitly as
+ * current->mm or explicitly with get_task_mm() or similar).
+ * We can't race against any other mmu notifier method either
+ * thanks to mm_take_all_locks().
+ */
+ if (mmu_notifier_mm)
+ mm->mmu_notifier_mm = mmu_notifier_mm;
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ hlist_add_head_rcu(&mn->hlist, &mm->mmu_notifier_mm->list);
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+
+ mm_drop_all_locks(mm);
+ BUG_ON(atomic_read(&mm->mm_users) <= 0);
+ return 0;
+
+out_clean:
+ kfree(mmu_notifier_mm);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__mmu_notifier_register);
+
+/**
+ * mmu_notifier_register - Register a notifier on a mm
+ * @mn: The notifier to attach
+ * @mm: The mm to attach the notifier to
+ *
+ * Must not hold mmap_sem nor any other VM related lock when calling
+ * this registration function. Must also ensure mm_users can't go down
+ * to zero while this runs to avoid races with mmu_notifier_release,
+ * so mm has to be current->mm or the mm should be pinned safely such
+ * as with get_task_mm(). If the mm is not current->mm, the mm_users
+ * pin should be released by calling mmput after mmu_notifier_register
+ * returns.
+ *
+ * mmu_notifier_unregister() or mmu_notifier_put() must be always called to
+ * unregister the notifier.
+ *
+ * While the caller has a mmu_notifier get the mn->mm pointer will remain
+ * valid, and can be converted to an active mm pointer via mmget_not_zero().
+ */
+int mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ int ret;
+
+ down_write(&mm->mmap_sem);
+ ret = __mmu_notifier_register(mn, mm);
+ up_write(&mm->mmap_sem);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_register);
+
+static struct mmu_notifier *
+find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops)
+{
+ struct mmu_notifier *mn;
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ hlist_for_each_entry_rcu (mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops != ops)
+ continue;
+
+ if (likely(mn->users != UINT_MAX))
+ mn->users++;
+ else
+ mn = ERR_PTR(-EOVERFLOW);
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ return mn;
+ }
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ return NULL;
+}
+
+/**
+ * mmu_notifier_get_locked - Return the single struct mmu_notifier for
+ * the mm & ops
+ * @ops: The operations struct being subscribe with
+ * @mm : The mm to attach notifiers too
+ *
+ * This function either allocates a new mmu_notifier via
+ * ops->alloc_notifier(), or returns an already existing notifier on the
+ * list. The value of the ops pointer is used to determine when two notifiers
+ * are the same.
+ *
+ * Each call to mmu_notifier_get() must be paired with a call to
+ * mmu_notifier_put(). The caller must hold the write side of mm->mmap_sem.
+ *
+ * While the caller has a mmu_notifier get the mm pointer will remain valid,
+ * and can be converted to an active mm pointer via mmget_not_zero().
+ */
+struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
+ struct mm_struct *mm)
+{
+ struct mmu_notifier *mn;
+ int ret;
+
+ lockdep_assert_held_write(&mm->mmap_sem);
+
+ if (mm->mmu_notifier_mm) {
+ mn = find_get_mmu_notifier(mm, ops);
+ if (mn)
+ return mn;
+ }
+
+ mn = ops->alloc_notifier(mm);
+ if (IS_ERR(mn))
+ return mn;
+ mn->ops = ops;
+ ret = __mmu_notifier_register(mn, mm);
+ if (ret)
+ goto out_free;
+ return mn;
+out_free:
+ mn->ops->free_notifier(mn);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_get_locked);
+
+/* this is called after the last mmu_notifier_unregister() returned */
+void __mmu_notifier_mm_destroy(struct mm_struct *mm)
+{
+ BUG_ON(!hlist_empty(&mm->mmu_notifier_mm->list));
+ kfree(mm->mmu_notifier_mm);
+ mm->mmu_notifier_mm = LIST_POISON1; /* debug */
+}
+
+/*
+ * This releases the mm_count pin automatically and frees the mm
+ * structure if it was the last user of it. It serializes against
+ * running mmu notifiers with SRCU and against mmu_notifier_unregister
+ * with the unregister lock + SRCU. All sptes must be dropped before
+ * calling mmu_notifier_unregister. ->release or any other notifier
+ * method may be invoked concurrently with mmu_notifier_unregister,
+ * and only after mmu_notifier_unregister returned we're guaranteed
+ * that ->release or any other method can't run anymore.
+ */
+void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ BUG_ON(atomic_read(&mm->mm_count) <= 0);
+
+ if (!hlist_unhashed(&mn->hlist)) {
+ /*
+ * SRCU here will force exit_mmap to wait for ->release to
+ * finish before freeing the pages.
+ */
+ int id;
+
+ id = srcu_read_lock(&srcu);
+ /*
+ * exit_mmap will block in mmu_notifier_release to guarantee
+ * that ->release is called before freeing the pages.
+ */
+ if (mn->ops->release)
+ mn->ops->release(mn, mm);
+ srcu_read_unlock(&srcu, id);
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ /*
+ * Can not use list_del_rcu() since __mmu_notifier_release
+ * can delete it before we hold the lock.
+ */
+ hlist_del_init_rcu(&mn->hlist);
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ }
+
+ /*
+ * Wait for any running method to finish, of course including
+ * ->release if it was run by mmu_notifier_release instead of us.
+ */
+ synchronize_srcu(&srcu);
+
+ BUG_ON(atomic_read(&mm->mm_count) <= 0);
+
+ mmdrop(mm);
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_unregister);
+
+static void mmu_notifier_free_rcu(struct rcu_head *rcu)
+{
+ struct mmu_notifier *mn = container_of(rcu, struct mmu_notifier, rcu);
+ struct mm_struct *mm = mn->mm;
+
+ mn->ops->free_notifier(mn);
+ /* Pairs with the get in __mmu_notifier_register() */
+ mmdrop(mm);
+}
+
+/**
+ * mmu_notifier_put - Release the reference on the notifier
+ * @mn: The notifier to act on
+ *
+ * This function must be paired with each mmu_notifier_get(), it releases the
+ * reference obtained by the get. If this is the last reference then process
+ * to free the notifier will be run asynchronously.
+ *
+ * Unlike mmu_notifier_unregister() the get/put flow only calls ops->release
+ * when the mm_struct is destroyed. Instead free_notifier is always called to
+ * release any resources held by the user.
+ *
+ * As ops->release is not guaranteed to be called, the user must ensure that
+ * all sptes are dropped, and no new sptes can be established before
+ * mmu_notifier_put() is called.
+ *
+ * This function can be called from the ops->release callback, however the
+ * caller must still ensure it is called pairwise with mmu_notifier_get().
+ *
+ * Modules calling this function must call mmu_notifier_synchronize() in
+ * their __exit functions to ensure the async work is completed.
+ */
+void mmu_notifier_put(struct mmu_notifier *mn)
+{
+ struct mm_struct *mm = mn->mm;
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ if (WARN_ON(!mn->users) || --mn->users)
+ goto out_unlock;
+ hlist_del_init_rcu(&mn->hlist);
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+
+ call_srcu(&srcu, &mn->rcu, mmu_notifier_free_rcu);
+ return;
+
+out_unlock:
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_put);
+
+/**
+ * mmu_notifier_synchronize - Ensure all mmu_notifiers are freed
+ *
+ * This function ensures that all outstanding async SRU work from
+ * mmu_notifier_put() is completed. After it returns any mmu_notifier_ops
+ * associated with an unused mmu_notifier will no longer be called.
+ *
+ * Before using the caller must ensure that all of its mmu_notifiers have been
+ * fully released via mmu_notifier_put().
+ *
+ * Modules using the mmu_notifier_put() API should call this in their __exit
+ * function to avoid module unloading races.
+ */
+void mmu_notifier_synchronize(void)
+{
+ synchronize_srcu(&srcu);
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_synchronize);
+
+bool
+mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range)
+{
+ if (!range->vma || range->event != MMU_NOTIFY_PROTECTION_VMA)
+ return false;
+ /* Return true if the vma still have the read flag set. */
+ return range->vma->vm_flags & VM_READ;
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_range_update_to_read_only);