22 files changed, 377 insertions, 0 deletions
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
new file mode 100644
index 000000000000..cc9f4e6a2d23
--- /dev/null
+++ b/rust/helpers/blk.c
@@ -0,0 +1,14 @@
+// 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);
+}
+
+struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
+{
+	return blk_mq_rq_from_pdu(pdu);
+}
diff --git a/rust/helpers/bug.c b/rust/helpers/bug.c
new file mode 100644
index 000000000000..e2d13babc737
--- /dev/null
+++ b/rust/helpers/bug.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bug.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+	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..e994f7b5928c
--- /dev/null
+++ b/rust/helpers/build_bug.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/errname.h>
+
+const char *rust_helper_errname(int err)
+{
+	return errname(err);
+}
diff --git a/rust/helpers/cred.c b/rust/helpers/cred.c
new file mode 100644
index 000000000000..fde7ae20cdd1
--- /dev/null
+++ b/rust/helpers/cred.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cred.h>
+
+const struct cred *rust_helper_get_cred(const struct cred *cred)
+{
+	return get_cred(cred);
+}
+
+void rust_helper_put_cred(const struct cred *cred)
+{
+	put_cred(cred);
+}
diff --git a/rust/helpers/err.c b/rust/helpers/err.c
new file mode 100644
index 000000000000..be3d45ef78a2
--- /dev/null
+++ b/rust/helpers/err.c
@@ -0,0 +1,19 @@
+// 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);
+}
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+	return IS_ERR(ptr);
+}
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+	return PTR_ERR(ptr);
+}
diff --git a/rust/helpers/fs.c b/rust/helpers/fs.c
new file mode 100644
index 000000000000..a75c96763372
--- /dev/null
+++ b/rust/helpers/fs.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2024 Google LLC.
+ */
+
+#include <linux/fs.h>
+
+struct file *rust_helper_get_file(struct file *f)
+{
+	return get_file(f);
+}
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
new file mode 100644
index 000000000000..463b970154de
--- /dev/null
+++ b/rust/helpers/helpers.c
@@ -0,0 +1,30 @@
+// 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.
+ *
+ * Sorted alphabetically.
+ */
+
+#include "blk.c"
+#include "bug.c"
+#include "build_assert.c"
+#include "build_bug.c"
+#include "cred.c"
+#include "err.c"
+#include "fs.c"
+#include "jump_label.c"
+#include "kunit.c"
+#include "mutex.c"
+#include "page.c"
+#include "rbtree.c"
+#include "refcount.c"
+#include "security.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/jump_label.c b/rust/helpers/jump_label.c
new file mode 100644
index 000000000000..fc1f1e0df08e
--- /dev/null
+++ b/rust/helpers/jump_label.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2024 Google LLC.
+ */
+
+#include <linux/jump_label.h>
+
+#ifndef CONFIG_JUMP_LABEL
+int rust_helper_static_key_count(struct static_key *key)
+{
+	return static_key_count(key);
+}
+#endif
diff --git a/rust/helpers/kunit.c b/rust/helpers/kunit.c
new file mode 100644
index 000000000000..9d725067eb3b
--- /dev/null
+++ b/rust/helpers/kunit.c
@@ -0,0 +1,9 @@
+// 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();
+}
diff --git a/rust/helpers/mutex.c b/rust/helpers/mutex.c
new file mode 100644
index 000000000000..a17ca8cdb50c
--- /dev/null
+++ b/rust/helpers/mutex.c
@@ -0,0 +1,15 @@
+// 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);
+}
+
+void rust_helper___mutex_init(struct mutex *mutex, const char *name,
+			      struct lock_class_key *key)
+{
+	__mutex_init(mutex, name, key);
+}
diff --git a/rust/helpers/page.c b/rust/helpers/page.c
new file mode 100644
index 000000000000..b3f2b8fbf87f
--- /dev/null
+++ b/rust/helpers/page.c
@@ -0,0 +1,19 @@
+// 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);
+}
+
+void *rust_helper_kmap_local_page(struct page *page)
+{
+	return kmap_local_page(page);
+}
+
+void rust_helper_kunmap_local(const void *addr)
+{
+	kunmap_local(addr);
+}
diff --git a/rust/helpers/rbtree.c b/rust/helpers/rbtree.c
new file mode 100644
index 000000000000..6d404b84a9b5
--- /dev/null
+++ b/rust/helpers/rbtree.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/rbtree.h>
+
+void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
+			      struct rb_node **rb_link)
+{
+	rb_link_node(node, parent, rb_link);
+}
diff --git a/rust/helpers/refcount.c b/rust/helpers/refcount.c
new file mode 100644
index 000000000000..f47afc148ec3
--- /dev/null
+++ b/rust/helpers/refcount.c
@@ -0,0 +1,19 @@
+// 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);
+}
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}
diff --git a/rust/helpers/security.c b/rust/helpers/security.c
new file mode 100644
index 000000000000..239e5b4745fe
--- /dev/null
+++ b/rust/helpers/security.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/security.h>
+
+#ifndef CONFIG_SECURITY
+void rust_helper_security_cred_getsecid(const struct cred *c, u32 *secid)
+{
+	security_cred_getsecid(c, secid);
+}
+
+int rust_helper_security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+{
+	return security_secid_to_secctx(secid, secdata, seclen);
+}
+
+void rust_helper_security_release_secctx(char *secdata, u32 seclen)
+{
+	security_release_secctx(secdata, seclen);
+}
+#endif
diff --git a/rust/helpers/signal.c b/rust/helpers/signal.c
new file mode 100644
index 000000000000..63c407f80c26
--- /dev/null
+++ b/rust/helpers/signal.c
@@ -0,0 +1,9 @@
+// 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);
+}
diff --git a/rust/helpers/slab.c b/rust/helpers/slab.c
new file mode 100644
index 000000000000..f043e087f9d6
--- /dev/null
+++ b/rust/helpers/slab.c
@@ -0,0 +1,9 @@
+// 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);
+}
diff --git a/rust/helpers/spinlock.c b/rust/helpers/spinlock.c
new file mode 100644
index 000000000000..92f7fc418425
--- /dev/null
+++ b/rust/helpers/spinlock.c
@@ -0,0 +1,28 @@
+// 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
+# if defined(CONFIG_PREEMPT_RT)
+	__spin_lock_init(lock, name, key, false);
+# else /*!CONFIG_PREEMPT_RT */
+	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+# endif /* CONFIG_PREEMPT_RT */
+#else /* !CONFIG_DEBUG_SPINLOCK */
+	spin_lock_init(lock);
+#endif /* CONFIG_DEBUG_SPINLOCK */
+}
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}
diff --git a/rust/helpers/task.c b/rust/helpers/task.c
new file mode 100644
index 000000000000..7d66487db831
--- /dev/null
+++ b/rust/helpers/task.c
@@ -0,0 +1,57 @@
+// 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;
+}
+
+void rust_helper_get_task_struct(struct task_struct *t)
+{
+	get_task_struct(t);
+}
+
+void rust_helper_put_task_struct(struct task_struct *t)
+{
+	put_task_struct(t);
+}
+
+kuid_t rust_helper_task_uid(struct task_struct *task)
+{
+	return task_uid(task);
+}
+
+kuid_t rust_helper_task_euid(struct task_struct *task)
+{
+	return task_euid(task);
+}
+
+#ifndef CONFIG_USER_NS
+uid_t rust_helper_from_kuid(struct user_namespace *to, kuid_t uid)
+{
+	return from_kuid(to, uid);
+}
+#endif /* CONFIG_USER_NS */
+
+bool rust_helper_uid_eq(kuid_t left, kuid_t right)
+{
+	return uid_eq(left, right);
+}
+
+kuid_t rust_helper_current_euid(void)
+{
+	return current_euid();
+}
+
+struct user_namespace *rust_helper_current_user_ns(void)
+{
+	return current_user_ns();
+}
+
+pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk,
+				  struct pid_namespace *ns)
+{
+	return task_tgid_nr_ns(tsk, ns);
+}
diff --git a/rust/helpers/uaccess.c b/rust/helpers/uaccess.c
new file mode 100644
index 000000000000..f49076f813cd
--- /dev/null
+++ b/rust/helpers/uaccess.c
@@ -0,0 +1,15 @@
+// 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);
+}
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from,
+				       unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}
diff --git a/rust/helpers/wait.c b/rust/helpers/wait.c
new file mode 100644
index 000000000000..c7336bbf2750
--- /dev/null
+++ b/rust/helpers/wait.c
@@ -0,0 +1,9 @@
+// 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);
+}
diff --git a/rust/helpers/workqueue.c b/rust/helpers/workqueue.c
new file mode 100644
index 000000000000..f59427acc323
--- /dev/null
+++ b/rust/helpers/workqueue.c
@@ -0,0 +1,15 @@
+// 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;
+}