17 files changed, 296 insertions, 0 deletions
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
new file mode 100644
index 000000000000..d99c965eb59b
--- /dev/null
+++ b/rust/helpers/blk.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/blk-mq.h>
+#include <linux/blkdev.h>
+
+void *rust_helper_blk_mq_rq_to_pdu(struct request *rq)
+{
+	return blk_mq_rq_to_pdu(rq);
+}
+EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_to_pdu);
+
+struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
+{
+	return blk_mq_rq_from_pdu(pdu);
+}
+EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_from_pdu);
diff --git a/rust/helpers/bug.c b/rust/helpers/bug.c
new file mode 100644
index 000000000000..e2afbad23dcd
--- /dev/null
+++ b/rust/helpers/bug.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bug.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+	BUG();
+}
+EXPORT_SYMBOL_GPL(rust_helper_BUG);
diff --git a/rust/helpers/build_assert.c b/rust/helpers/build_assert.c
new file mode 100644
index 000000000000..6a54b2680b14
--- /dev/null
+++ b/rust/helpers/build_assert.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/build_bug.h>
+
+/*
+ * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
+ * use it in contexts where Rust expects a `usize` like slice (array) indices.
+ * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
+ * pointer) but not necessarily the same as `size_t` (can hold the size of any
+ * single object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to add
+ * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+	sizeof(size_t) == sizeof(uintptr_t) &&
+	__alignof__(size_t) == __alignof__(uintptr_t),
+	"Rust code expects C `size_t` to match Rust `usize`"
+);
diff --git a/rust/helpers/build_bug.c b/rust/helpers/build_bug.c
new file mode 100644
index 000000000000..f3106f248485
--- /dev/null
+++ b/rust/helpers/build_bug.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/errname.h>
+
+const char *rust_helper_errname(int err)
+{
+	return errname(err);
+}
+EXPORT_SYMBOL_GPL(rust_helper_errname);
diff --git a/rust/helpers/err.c b/rust/helpers/err.c
new file mode 100644
index 000000000000..fba4e0be64f5
--- /dev/null
+++ b/rust/helpers/err.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <linux/export.h>
+
+__force void *rust_helper_ERR_PTR(long err)
+{
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+	return IS_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+	return PTR_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
new file mode 100644
index 000000000000..2b54f22e8774
--- /dev/null
+++ b/rust/helpers/helpers.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+ * cannot be called either. This file explicitly creates functions ("helpers")
+ * that wrap those so that they can be called from Rust.
+ *
+ * Even though Rust kernel modules should never use the bindings directly, some
+ * of these helpers need to be exported because Rust generics and inlined
+ * functions may not get their code generated in the crate where they are
+ * defined. Other helpers, called from non-inline functions, may not be
+ * exported, in principle. However, in general, the Rust compiler does not
+ * guarantee codegen will be performed for a non-inline function either.
+ * Therefore, this file exports all the helpers. In the future, this may be
+ * revisited to reduce the number of exports after the compiler is informed
+ * about the places codegen is required.
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ *
+ * Sorted alphabetically.
+ */
+
+#include "blk.c"
+#include "bug.c"
+#include "build_assert.c"
+#include "build_bug.c"
+#include "err.c"
+#include "kunit.c"
+#include "mutex.c"
+#include "page.c"
+#include "refcount.c"
+#include "signal.c"
+#include "slab.c"
+#include "spinlock.c"
+#include "task.c"
+#include "uaccess.c"
+#include "wait.c"
+#include "workqueue.c"
diff --git a/rust/helpers/kunit.c b/rust/helpers/kunit.c
new file mode 100644
index 000000000000..905e4ff4424a
--- /dev/null
+++ b/rust/helpers/kunit.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <kunit/test-bug.h>
+#include <linux/export.h>
+
+struct kunit *rust_helper_kunit_get_current_test(void)
+{
+	return kunit_get_current_test();
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
diff --git a/rust/helpers/mutex.c b/rust/helpers/mutex.c
new file mode 100644
index 000000000000..29fd141c387d
--- /dev/null
+++ b/rust/helpers/mutex.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/mutex.h>
+
+void rust_helper_mutex_lock(struct mutex *lock)
+{
+	mutex_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
diff --git a/rust/helpers/page.c b/rust/helpers/page.c
new file mode 100644
index 000000000000..7fd333411a88
--- /dev/null
+++ b/rust/helpers/page.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	return alloc_pages(gfp_mask, order);
+}
+EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
+
+void *rust_helper_kmap_local_page(struct page *page)
+{
+	return kmap_local_page(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kmap_local_page);
+
+void rust_helper_kunmap_local(const void *addr)
+{
+	kunmap_local(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunmap_local);
diff --git a/rust/helpers/refcount.c b/rust/helpers/refcount.c
new file mode 100644
index 000000000000..13ab64805f77
--- /dev/null
+++ b/rust/helpers/refcount.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/refcount.h>
+
+refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+	return (refcount_t)REFCOUNT_INIT(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
diff --git a/rust/helpers/signal.c b/rust/helpers/signal.c
new file mode 100644
index 000000000000..d44e8096b8a9
--- /dev/null
+++ b/rust/helpers/signal.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/sched/signal.h>
+
+int rust_helper_signal_pending(struct task_struct *t)
+{
+	return signal_pending(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
diff --git a/rust/helpers/slab.c b/rust/helpers/slab.c
new file mode 100644
index 000000000000..3e0a1a173d8a
--- /dev/null
+++ b/rust/helpers/slab.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/slab.h>
+
+void * __must_check __realloc_size(2)
+rust_helper_krealloc(const void *objp, size_t new_size, gfp_t flags)
+{
+	return krealloc(objp, new_size, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_krealloc);
diff --git a/rust/helpers/spinlock.c b/rust/helpers/spinlock.c
new file mode 100644
index 000000000000..04fd8ddb4986
--- /dev/null
+++ b/rust/helpers/spinlock.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/spinlock.h>
+
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+				  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+#else
+	spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
diff --git a/rust/helpers/task.c b/rust/helpers/task.c
new file mode 100644
index 000000000000..b176c347f0d4
--- /dev/null
+++ b/rust/helpers/task.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/sched/task.h>
+
+struct task_struct *rust_helper_get_current(void)
+{
+	return current;
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_current);
+
+void rust_helper_get_task_struct(struct task_struct *t)
+{
+	get_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
+
+void rust_helper_put_task_struct(struct task_struct *t)
+{
+	put_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
diff --git a/rust/helpers/uaccess.c b/rust/helpers/uaccess.c
new file mode 100644
index 000000000000..3d004ac1c180
--- /dev/null
+++ b/rust/helpers/uaccess.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/uaccess.h>
+
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from,
+					 unsigned long n)
+{
+	return copy_from_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from,
+				       unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
diff --git a/rust/helpers/wait.c b/rust/helpers/wait.c
new file mode 100644
index 000000000000..bf361f40c7cb
--- /dev/null
+++ b/rust/helpers/wait.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/wait.h>
+
+void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
+{
+	init_wait(wq_entry);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_wait);
diff --git a/rust/helpers/workqueue.c b/rust/helpers/workqueue.c
new file mode 100644
index 000000000000..12e2ee66aa4f
--- /dev/null
+++ b/rust/helpers/workqueue.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/workqueue.h>
+
+void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
+				    bool onstack, const char *name,
+				    struct lock_class_key *key)
+{
+	__init_work(work, onstack);
+	work->data = (atomic_long_t)WORK_DATA_INIT();
+	lockdep_init_map(&work->lockdep_map, name, key, 0);
+	INIT_LIST_HEAD(&work->entry);
+	work->func = func;
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_work_with_key);