Merge branch 'rust-device-v6.9-rc3' into rust-pci-v6.9-rc3

Author: metaspace

arch/x86/tools/insn_decoder_test.c

@@ -106,7 +106,7 @@ static void parse_args(int argc, char **argv)
 	}
 }
 
-#define BUFSIZE 256
+#define BUFSIZE 1024
 
 int main(int argc, char **argv)
 {

rust/Makefile

@@ -6,10 +6,24 @@ rustdoc_output := $(objtree)/Documentation/output/rust/rustdoc
 obj-$(CONFIG_RUST) += core.o compiler_builtins.o
 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
+RUST_HELPERS := \
+	bug \
+	build_assert \
+	build_bug \
+	device \
+	err \
+	kunit \
+	mutex \
+	rcu \
+	refcount \
+	signal \
+	spinlock\
+	task \
+	wait \
+	workqueue
+
+export RUST_HELPERS
+obj-y += helpers/
 
 always-$(CONFIG_RUST) += libmacros.so
 no-clean-files += libmacros.so
@@ -339,6 +353,10 @@ quiet_cmd_bindgen = BINDGEN $@
 		-o $@ -- $(bindgen_c_flags_final) -DMODULE \
 		$(bindgen_target_cflags) $(bindgen_target_extra)
 
+quiet_cmd_cat = CAT     $@
+      cmd_cat = \
+	cat $(patsubst %,$(srctree)/$(src)/helpers/%.c, $(RUST_HELPERS)) > $@
+
 $(obj)/bindings/bindings_generated.rs: private bindgen_target_flags = \
     $(shell grep -Ev '^#|^$$' $(srctree)/$(src)/bindgen_parameters)
 $(obj)/bindings/bindings_generated.rs: private bindgen_target_extra = ; \
@@ -353,9 +371,9 @@ $(obj)/uapi/uapi_generated.rs: $(src)/uapi/uapi_helper.h \
     $(src)/bindgen_parameters FORCE
 	$(call if_changed_dep,bindgen)
 
-# See `CFLAGS_REMOVE_helpers.o` above. In addition, Clang on C does not warn
-# with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed here
-# given it is `libclang`; but for consistency, future Clang changes and/or
+# See `ccflags-remove-y` in helpers/Makefile . In addition, Clang on C does not
+# warn with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed
+# here given it is `libclang`; but for consistency, future Clang changes and/or
 # a potential future GCC backend for `bindgen`, we disable it too.
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_flags = \
     --blocklist-type '.*' --allowlist-var '' \
@@ -364,9 +382,13 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
     -I$(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: $(obj)/helpers/helpers_combined.c FORCE
 	$(call if_changed_dep,bindgen)
 
+targets += helpers/helpers_combined.c
+$(obj)/helpers/helpers_combined.c: $(patsubst %,$(src)/helpers/%.c, $(RUST_HELPERS)) FORCE
+	$(call if_changed,cat)
+
 quiet_cmd_exports = EXPORTS $@
       cmd_exports = \
 	$(NM) -p --defined-only $< \

rust/bindings/bindings_helper.h

@@ -7,6 +7,7 @@
  */
 
 #include <kunit/test.h>
+#include <linux/device.h>
 #include <linux/errname.h>
 #include <linux/ethtool.h>
 #include <linux/jiffies.h>

rust/helpers.c

@@ -0,0 +1,7 @@
+
+# Note: `RUST_HELPERS` is defined in `../Makefile`
+
+# Missing prototypes are expected in the helpers since these are exported
+# for Rust only, thus there is no header nor prototypes.
+obj-$(CONFIG_RUST) += $(patsubst %,%.o, $(RUST_HELPERS))
+ccflags-remove-y += -Wmissing-prototypes -Wmissing-declarations

rust/helpers/Makefile

@@ -0,0 +1,18 @@
+# Rust Helpers
+
+Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+cannot be called either. The files in this directory explicitly create functions
+("helpers") that wrap those so that they can be called from Rust.
+
+Even though Rust kernel modules should never use directly the bindings, 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.

rust/helpers/README.md

@@ -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);

rust/helpers/bug.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`"
+);

rust/helpers/build_assert.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);

rust/helpers/build_bug.c

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/device.h>
+
+void *rust_helper_dev_get_drvdata(struct device *dev)
+{
+	return dev_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_get_drvdata);
+
+const char *rust_helper_dev_name(const struct device *dev)
+{
+	return dev_name(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_name);