Commit e26fa546 authored by Gary Guo's avatar Gary Guo Committed by Miguel Ojeda
Browse files

rust: kbuild: auto generate helper exports 



This removes the need to explicitly export all symbols.

Generate helper exports similarly to what's currently done for Rust
crates. These helpers are exclusively called from within Rust code and
therefore can be treated similar as other Rust symbols.

Signed-off-by: default avatarGary Guo <gary@garyguo.net>
Reviewed-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Tested-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240817165302.3852499-1-gary@garyguo.net


[ Fixed dependency path, reworded slightly, edited comment a bit and
  rebased on top of the changes made when applying Andreas' patch
  (e.g. no `README.md` anymore, so moved the edits).  - Miguel ]
Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent c4d7f546

rust/Makefile

+14 −2
Original line number Diff line number Diff line
@@ -16,8 +16,8 @@ no-clean-files += libmacros.so 


always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs

obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o

always-$(CONFIG_RUST) += exports_alloc_generated.h exports_bindings_generated.h \

    exports_kernel_generated.h

always-$(CONFIG_RUST) += exports_alloc_generated.h exports_helpers_generated.h \

    exports_bindings_generated.h exports_kernel_generated.h



always-$(CONFIG_RUST) += uapi/uapi_generated.rs

obj-$(CONFIG_RUST) += uapi.o
@@ -313,6 +313,18 @@ $(obj)/exports_core_generated.h: $(obj)/core.o FORCE 
$(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE

	$(call if_changed,exports)



# Even though Rust kernel modules should never use the bindings directly,

# symbols from the `bindings` crate and the C 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, we export all symbols from helpers and bindings.

# In the future, this may be revisited to reduce the number of exports after

# the compiler is informed about the places codegen is required.

$(obj)/exports_helpers_generated.h: $(obj)/helpers/helpers.o FORCE

	$(call if_changed,exports)



$(obj)/exports_bindings_generated.h: $(obj)/bindings.o FORCE

	$(call if_changed,exports)

rust/exports.c

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include "exports_core_generated.h"

#include "exports_alloc_generated.h"

#include "exports_helpers_generated.h"

#include "exports_bindings_generated.h"

#include "exports_kernel_generated.h"

rust/helpers/blk.c

+0 −2
Original line number Diff line number Diff line
@@ -7,10 +7,8 @@ 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);

rust/helpers/bug.c

+0 −1
Original line number Diff line number Diff line
@@ -6,4 +6,3 @@ __noreturn void rust_helper_BUG(void) 
{

	BUG();

}
 
EXPORT_SYMBOL_GPL(rust_helper_BUG);

rust/helpers/build_bug.c

+0 −1
Original line number Diff line number Diff line
@@ -7,4 +7,3 @@ const char *rust_helper_errname(int err) 
{

	return errname(err);

}
 
EXPORT_SYMBOL_GPL(rust_helper_errname);