Am 13.09.24 um 23:44 schrieb Alice Ryhl:
On Fri, Sep 13, 2024 at 11:18 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
On Fri, Sep 13, 2024 at 12:08:20AM +0200, Miguel Ojeda wrote:
On Thu, Aug 29, 2024 at 10:23 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote:
Add all of the flags that are needed to support the shadow call stack
(SCS) sanitizer with Rust, and updates Kconfig to allow only
configurations that work.
Applied to `rust-next` -- thanks everyone!
Paul/Palmer/Albert/RISC-V: I think you were not Cc'd (at least in this
version?), so please shout if you have a problem with this.
For some reason I deleted the series from my mailbox, must've been in
dt-binding review mode and hit ctrl + d. I've been away and busy, so my
apologies Alice for not trying this out sooner.
It's sorta annoying to test rust + scs on riscv, cos you need (unless I
am mistaken) llvm-19. llvm-18 + rust built fine, but has no SCS.
llvm-19 + rust failed to build for me riscv, producing:
In file included from /stuff/linux/rust/helpers/helpers.c:22:
/stuff/linux/rust/helpers/spinlock.c:10:23: error: call to undeclared function 'spinlock_check'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
^
/stuff/linux/rust/helpers/spinlock.c:10:23: error: incompatible integer to pointer conversion passing 'int' to parameter of type 'raw_spinlock_t *' (aka 'struct raw_spinlock *') [-Wint-conversion]
__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
^~~~~~~~~~~~~~~~~~~~
/stuff/linux/include/linux/spinlock.h:101:52: note: passing argument to parameter 'lock' here
extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
^
2 errors generated.
This occurs because I have DEBUG_SPINLOCK enabled. I didn't check why,
but Andreas seems to have introduced that code - luckily he's already on
CC here :)
With that disabled, there are dozens of warnings along the lines of:
/stuff/linux/rust/helpers/err.c:6:14: warning: symbol 'rust_helper_ERR_PTR' was not declared. Should it be static?
If those are okay for rust code, it would be rather helpful if the
warnings could be disabled - otherwise they should really be fixed.
Following that, I got a build error:
error[E0425]: cannot find function `__mutex_init` in crate `bindings`
--> /stuff/linux/rust/kernel/sync/lock/mutex.rs:104:28
|
104 | unsafe { bindings::__mutex_init(ptr, name, key) }
| ^^^^^^^^^^^^ help: a function with a similar name exists: `__mutex_rt_init`
|
::: /stuff/brsdk/work/linux/rust/bindings/bindings_generated.rs:12907:5
|
12907 | / pub fn __mutex_rt_init(
12908 | | lock: *mut mutex,
12909 | | name: *const core::ffi::c_char,
12910 | | key: *mut lock_class_key,
12911 | | );
| |_____- similarly named function `__mutex_rt_init` defined here
error: aborting due to 1 previous error
This looks like an unrelated problem to me.
Yes, it is unrelated to this change. It is PREEMPT_RT usage related. I
think we could add something like
#ifdef CONFIG_PREEMPT_RT
void rust_helper___mutex_init(struct mutex *mutex, const char *name,
struct lock_class_key *key)
{
return __mutex_init(mutex, name, key);
}
#endif
to helpers to fix
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/rust/kernel/sync/lock/mutex.rs?&id=6d20d629c6d8575be98eeebe49a16fb2d7b32350
?
Explanation: Looking at
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/mutex.h?#n52
we have (simplified)
#ifndef CONFIG_PREEMPT_RT
extern void __mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
#else
#define __mutex_init(mutex, name, key) \
do { \
rt_mutex_base_init(&(mutex)->rtmutex); \
__mutex_rt_init((mutex), name, key); \
} while (0)
#endif
So in the CONFIG_PREEMPT_RT case bindgen doesn't resolve the macro
what could be fixed by adding a helper.
Dirk
This patch only changes
the rustc flags, but these errors have to do with the Rust
helpers/bindings, which get generated before the rustc flags are used
at all. Most likely, there is a problem under the particular
configuration you are using. Were you able to reproduce these errors
without this patch?
I stopped there, Space Marine 2 awaits.
Hopefully I'll get to say hello next week,
Conor.
Thanks for taking a look, and see you at Plumbers!
Alice
