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rust: kbuild: split up helpers.c

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This patch splits up the rust helpers C file. When rebasing patch sets on
upstream linux, merge conflicts in helpers.c is common and time consuming
[1]. Thus, split the file so that each kernel component can live in a
separate file.

This patch lists helper files explicitly and thus conflicts in the file
list is still likely. However, they should be more simple to resolve than
the conflicts usually seen in helpers.c.

[ Removed `README.md` and undeleted the original comment since now,
  in v3 of the series, we have a `helpers.c` again; which also allows
  us to keep the "Sorted alphabetically" line and makes the diff easier.

  In addition, updated the Documentation/ mentions of the file, reworded
  title and removed blank lines at the end of `page.c`.  - Miguel ]

Link: https://rust-for-linux.zulipchat.com/#narrow/stream/288089-General/topic/Splitting.20up.20helpers.2Ec/near/426694012 [1]
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240815103016.2771842-1-nmi@metaspace.dk
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Andreas Hindborg 2024-08-15 10:30:26 +00:00 committed by Miguel Ojeda
parent f1385dc670
commit 876346536c
20 changed files with 301 additions and 244 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/rust/general-information.rst
View File

@ -75,7 +75,7 @@ should provide as-safe-as-possible abstractions as needed.
.. code-block::
rust/bindings/
(rust/helpers.c)
(rust/helpers/)
include/ -----+ <-+
| |
@ -112,7 +112,7 @@ output files in the ``rust/bindings/`` directory.
For parts of the C header that ``bindgen`` does not auto generate, e.g. C
``inline`` functions or non-trivial macros, it is acceptable to add a small
wrapper function to ``rust/helpers.c`` to make it available for the Rust side as
wrapper function to ``rust/helpers/`` to make it available for the Rust side as
well.
Abstractions

6
rust/Makefile
View File

@ -8,8 +8,8 @@ always-$(CONFIG_RUST) += exports_core_generated.h
# Missing prototypes are expected in the helpers since these are exported
# for Rust only, thus there is no header nor prototypes.
obj-$(CONFIG_RUST) += helpers.o
CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations
obj-$(CONFIG_RUST) += helpers/helpers.o
CFLAGS_REMOVE_helpers/helpers.o = -Wmissing-prototypes -Wmissing-declarations
always-$(CONFIG_RUST) += libmacros.so
no-clean-files += libmacros.so
@ -299,7 +299,7 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
-I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n pub fn \1/g' $@
$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers.c FORCE
$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
$(call if_changed_dep,bindgen)
quiet_cmd_exports = EXPORTS $@

239
rust/helpers.c
View File

@ -1,239 +0,0 @@
// 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 <kunit/test-bug.h>
#include <linux/bug.h>
#include <linux/build_bug.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errname.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
__noreturn void rust_helper_BUG(void)
{
BUG();
}
EXPORT_SYMBOL_GPL(rust_helper_BUG);
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);
void rust_helper_mutex_lock(struct mutex *lock)
{
mutex_lock(lock);
}
EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
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);
void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
{
init_wait(wq_entry);
}
EXPORT_SYMBOL_GPL(rust_helper_init_wait);
int rust_helper_signal_pending(struct task_struct *t)
{
return signal_pending(t);
}
EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
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);
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);
__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);
const char *rust_helper_errname(int err)
{
return errname(err);
}
EXPORT_SYMBOL_GPL(rust_helper_errname);
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);
struct kunit *rust_helper_kunit_get_current_test(void)
{
return kunit_get_current_test();
}
EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
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);
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);
/*
* `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`"
);
// This will soon be moved to a separate file, so no need to merge with above.
#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);

16
rust/helpers/blk.c Normal file
View File

@ -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);

9
rust/helpers/bug.c Normal file
View File

@ -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);

25
rust/helpers/build_assert.c Normal file
View File

@ -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`"
);

10
rust/helpers/build_bug.c Normal file
View File

@ -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);

22
rust/helpers/err.c Normal file
View File

@ -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);

38
rust/helpers/helpers.c Normal file
View File

@ -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"

10
rust/helpers/kunit.c Normal file
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@ -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);

10
rust/helpers/mutex.c Normal file
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@ -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);

22
rust/helpers/page.c Normal file
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@ -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);

22
rust/helpers/refcount.c Normal file
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@ -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);

10
rust/helpers/signal.c Normal file
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@ -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);

10
rust/helpers/slab.c Normal file
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@ -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);

27
rust/helpers/spinlock.c Normal file
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@ -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);

22
rust/helpers/task.c Normal file
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@ -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);

17
rust/helpers/uaccess.c Normal file
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@ -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);

10
rust/helpers/wait.c Normal file
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@ -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);

16
rust/helpers/workqueue.c Normal file
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@ -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);