* [RFC PATCH v2 1/2] kbuild: Build Rust crates as libraries
2023-10-27 0:34 [RFC PATCH v2 0/2] rust: crates in other kernel directories Martin Rodriguez Reboredo
@ 2023-10-27 0:34 ` Martin Rodriguez Reboredo
2023-10-27 0:34 ` [RFC PATCH v2 2/2] samples: rust: Add USB sample bindings Martin Rodriguez Reboredo
1 sibling, 0 replies; 7+ messages in thread
From: Martin Rodriguez Reboredo @ 2023-10-27 0:34 UTC (permalink / raw)
To: Masahiro Yamada, Nathan Chancellor, Nick Desaulniers,
Nicolas Schier, Miguel Ojeda, Alex Gaynor, Wedson Almeida Filho,
Boqun Feng, Gary Guo, Björn Roy Baron, Benno Lossin,
Andreas Hindborg, Alice Ryhl, Andrew Davis, Rob Herring,
Shuah Khan, Andy Shevchenko, Chuck Lever
Cc: linux-kbuild, linux-kernel, rust-for-linux
Enables compiling Rust crates as dependencies of kernel modules. These
are also meant to be used as libraries for other parts of the kernel.
For these crates `bindings` is also exposed to them and they get their
symbols exported for them to be used by other code.
When a composite object depends on an `.rlib` file, which by the way is
a current ar archive, Kbuild will compile it from its base Rust source
and archive it.
This makes possible to have Rust bindings for a subsystem that is
compiled either built-in or as a module. They can also be made into
modules by themselves too.
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
v1 -> v2:
- Fixed kernel compilation.
- Added support for building crates as modules.
.gitignore | 2 ++
Makefile | 4 ++--
scripts/Makefile.build | 49 +++++++++++++++++++++++++++++++++++----
scripts/Makefile.lib | 18 +++++++++++---
scripts/Makefile.modfinal | 7 +++++-
5 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/.gitignore b/.gitignore
index 0bbae167bf93..8353b01e2915 100644
--- a/.gitignore
+++ b/.gitignore
@@ -38,6 +38,7 @@
*.o
*.o.*
*.patch
+*.rlib
*.rmeta
*.rpm
*.rsi
@@ -53,6 +54,7 @@
*.zst
Module.symvers
modules.order
+exports_*_generated.c
#
# Top-level generic files
diff --git a/Makefile b/Makefile
index 8a40530868ff..4113a5b93ddc 100644
--- a/Makefile
+++ b/Makefile
@@ -283,7 +283,7 @@ no-compiler-targets := $(no-dot-config-targets) install dtbs_install \
headers_install modules_install modules_sign kernelrelease image_name
no-sync-config-targets := $(no-dot-config-targets) %install modules_sign kernelrelease \
image_name
-single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rsi %.s %.symtypes %/
+single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rlib %.rsi %.s %.symtypes %/
config-build :=
mixed-build :=
@@ -1919,7 +1919,7 @@ $(clean-dirs):
clean: $(clean-dirs)
$(call cmd,rmfiles)
@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
- \( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \
+ \( -name '*.[aios]' -o -name '*.rlib' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \
-o -name '*.ko.*' \
-o -name '*.dtb' -o -name '*.dtbo' \
-o -name '*.dtb.S' -o -name '*.dtbo.S' \
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index da37bfa97211..11045ddba1a9 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -20,6 +20,7 @@ always-m :=
targets :=
subdir-y :=
subdir-m :=
+rust-libs :=
EXTRA_AFLAGS :=
EXTRA_CFLAGS :=
EXTRA_CPPFLAGS :=
@@ -243,9 +244,13 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
$(call if_changed_rule,cc_o_c)
$(call cmd,force_checksrc)
+mod_objs = $(call real-search, $*.o, .o, -objs -y -m)
+exports_objs = $(foreach m, $(sort $(basename \
+ $(filter $(notdir $(rlib-m)), $(mod_objs)))), exports_$m_generated.o)
+
# To make this rule robust against "Argument list too long" error,
# ensure to add $(obj)/ prefix by a shell command.
-cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \
+cmd_mod = printf '%s\n' $(mod_objs) $(exports_objs) | \
$(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@
$(obj)/%.mod: FORCE
@@ -274,7 +279,7 @@ rust_common_cmd = \
-Zcrate-attr='feature($(rust_allowed_features))' \
--extern alloc --extern kernel \
--crate-type rlib -L $(objtree)/rust/ \
- --crate-name $(basename $(notdir $@)) \
+ --crate-name $(basename $(notdir $<)) \
--out-dir $(dir $@) --emit=dep-info=$(depfile)
# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
@@ -285,11 +290,42 @@ rust_common_cmd = \
# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
# would not match each other.
+rlib_obj = $(dir $@)$*.$*.o
+rlib_meta = $(dir $@)$(patsubst %.rlib,%.rmeta,$(notdir $@))
+
quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<
+quiet_cmd_ln_rlib_o = SYMLINK $@
+ cmd_ln_rlib_o = ln -s -f $*.$*.o $@
+
$(obj)/%.o: $(src)/%.rs FORCE
- $(call if_changed_dep,rustc_o_rs)
+ $(if $(findstring $@, $(rlib-y) $(rlib-m)), \
+ $(call if_changed,ln_rlib_o), $(call if_changed_dep,rustc_o_rs))
+
+quiet_cmd_rustc_rlib_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+ cmd_rustc_rlib_rs = $(rust_common_cmd) --extern bindings \
+ --emit=obj=$(rlib_obj) --emit=metadata=$(rlib_meta) $<; \
+ rm -f $@; $(AR) cDPrST $@ $(rlib_obj) $(rlib_meta)
+
+quiet_cmd_rlib_exports = EXPORTS $@
+ cmd_rlib_exports = \
+ echo "\#include <linux/module.h>" > $@; \
+ $(NM) -p --defined-only $(rlib_obj) \
+ | grep -P ' (T|R|D) (?!(init|cleanup)_module)' | cut -d ' ' -f 3 \
+ | xargs -Isymbol \
+ echo 'extern int symbol; EXPORT_SYMBOL_GPL(symbol);' >> $@
+
+$(rlib-m): $(obj)/%.o: $(obj)/exports_%_generated.o $(obj)/lib%.rlib $(src)/%.rs FORCE
+
+$(obj)/lib%.rlib: $(src)/%.rs FORCE
+ $(call if_changed_dep,rustc_rlib_rs)
+
+$(obj)/exports_%_generated.c: $(obj)/lib%.rlib FORCE
+ $(call if_changed,rlib_exports)
+
+$(obj)/exports_%_generated.o: $(obj)/exports_%_generated.c FORCE
+ $(call if_changed,cc_o_c)
quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
cmd_rustc_rsi_rs = \
@@ -394,9 +430,14 @@ $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
# To make this rule robust against "Argument list too long" error,
# remove $(obj)/ prefix, and restore it by a shell command.
+# If we have a .rlib for the archive change it for its object member
+crate-obj = $(foreach m, $1, $(if $(findstring .rlib, $m), \
+ $(basename $(m:lib%=%)).$(m:lib%.rlib=%.o),$m))
+
quiet_cmd_ar_builtin = AR $@
cmd_ar_builtin = rm -f $@; \
- $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \
+ $(if $(real-prereqs), printf "$(obj)/%s " \
+ $(call crate-obj, $(patsubst $(obj)/%,%,$(real-prereqs))) | xargs) \
$(AR) cDPrST $@
$(obj)/built-in.a: $(real-obj-y) FORCE
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 68d0134bdbf9..3454b05dbbdc 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -45,12 +45,17 @@ else
obj-y := $(filter-out %/, $(obj-y))
endif
+rlib-y := $(foreach m, $(filter lib%.rlib, $(obj-y)), $(m:lib%.rlib=%.o))
+rlib-m := $(foreach m, $(filter lib%.rlib, $(obj-m)), $(m:lib%.rlib=%.o))
+
# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
# List composite targets that are constructed by combining other targets
multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
# List primitive targets that are compiled from source files
real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
+# List exported symbols from .rlib targets
+rlib-exports = $(foreach m, $1, $(if $(findstring .rlib, $m),$(m:lib%.rlib=exports_%_generated.o)) $m)
# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
@@ -59,7 +64,7 @@ multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
# Replace multi-part objects by their individual parts,
# including built-in.a from subdirectories
-real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
+real-obj-y := $(call rlib-exports, $(call real-search, $(obj-y), .o, -objs -y))
real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
always-y += $(always-m)
@@ -95,6 +100,8 @@ extra-y := $(addprefix $(obj)/,$(extra-y))
always-y := $(addprefix $(obj)/,$(always-y))
targets := $(addprefix $(obj)/,$(targets))
obj-m := $(addprefix $(obj)/,$(obj-m))
+rlib-y := $(addprefix $(obj)/,$(rlib-y))
+rlib-m := $(addprefix $(obj)/,$(rlib-m))
lib-y := $(addprefix $(obj)/,$(lib-y))
real-obj-y := $(addprefix $(obj)/,$(real-obj-y))
real-obj-m := $(addprefix $(obj)/,$(real-obj-m))
@@ -210,7 +217,11 @@ _cpp_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj)
endif
endif
-part-of-module = $(if $(filter $(basename $@).o, $(real-obj-m)),y)
+_rust_libs = $(foreach l, $(rust-libs), -L $(obj)/$(dir $l) --extern $(notdir $(basename $l)))
+
+part-of-module = \
+ $(if $(or $(filter $(basename $@).o, $(real-obj-m)), \
+ $(filter $(basename $@).rlib, $(real-obj-m))),y)
quiet_modtag = $(if $(part-of-module),[M], )
modkern_cflags = \
@@ -232,7 +243,8 @@ c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_c_flags) $(modkern_cflags) \
$(basename_flags) $(modname_flags)
-rust_flags = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
+rust_flags = $(_rust_flags) $(modkern_rustflags) $(_rust_libs) \
+ @$(objtree)/include/generated/rustc_cfg
a_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_a_flags) $(modkern_aflags)
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index b3a6aa8fbe8c..e05749a5ca0a 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -30,11 +30,16 @@ quiet_cmd_cc_o_c = CC [M] $@
ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
+# Symlinks of foo.o that point to foo.foo.o are members of a .rlib archives,
+# so their exports should be added to the module
+ko_objs = $(foreach o, $(filter %.o, $^),$(if \
+ $(filter-out %$o,$(realpath $o)),$(dir $o)exports_$(notdir $*)_generated.o) $o)
+
quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o += \
$(LD) -r $(KBUILD_LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
- -T scripts/module.lds -o $@ $(filter %.o, $^); \
+ -T scripts/module.lds -o $@ $(ko_objs); \
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
quiet_cmd_btf_ko = BTF [M] $@
--
2.42.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [RFC PATCH v2 2/2] samples: rust: Add USB sample bindings
2023-10-27 0:34 [RFC PATCH v2 0/2] rust: crates in other kernel directories Martin Rodriguez Reboredo
2023-10-27 0:34 ` [RFC PATCH v2 1/2] kbuild: Build Rust crates as libraries Martin Rodriguez Reboredo
@ 2023-10-27 0:34 ` Martin Rodriguez Reboredo
2023-10-27 3:21 ` Martin Rodriguez Reboredo
` (2 more replies)
1 sibling, 3 replies; 7+ messages in thread
From: Martin Rodriguez Reboredo @ 2023-10-27 0:34 UTC (permalink / raw)
To: Greg Kroah-Hartman, Miguel Ojeda, Alex Gaynor,
Wedson Almeida Filho, Boqun Feng, Gary Guo, Björn Roy Baron,
Benno Lossin, Andreas Hindborg, Alice Ryhl
Cc: linux-kbuild, linux-kernel, linux-usb, rust-for-linux
This is a demonstration of the capabilities of doing bindings with
subsystems that may or may not be statically linked.
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
drivers/usb/core/Kconfig | 7 +++++++
drivers/usb/core/Makefile | 3 +++
drivers/usb/core/usb.rs | 13 +++++++++++++
samples/rust/Kconfig | 10 ++++++++++
samples/rust/Makefile | 3 +++
samples/rust/rust_usb_simple.rs | 22 ++++++++++++++++++++++
6 files changed, 58 insertions(+)
create mode 100644 drivers/usb/core/usb.rs
create mode 100644 samples/rust/rust_usb_simple.rs
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index 351ede4b5de2..4b5604282129 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -116,3 +116,10 @@ config USB_AUTOSUSPEND_DELAY
The default value Linux has always had is 2 seconds. Change
this value if you want a different delay and cannot modify
the command line or module parameter.
+
+config USB_RUST
+ bool "Rust USB bindings"
+ depends on USB && RUST
+ default n
+ help
+ Enables Rust bindings for USB.
diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 7d338e9c0657..00e116913591 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -11,6 +11,7 @@ usbcore-y += phy.o port.o
usbcore-$(CONFIG_OF) += of.o
usbcore-$(CONFIG_USB_PCI) += hcd-pci.o
usbcore-$(CONFIG_ACPI) += usb-acpi.o
+usbcore-$(CONFIG_USB_RUST) += libusb.rlib
ifdef CONFIG_USB_ONBOARD_HUB
usbcore-y += ../misc/onboard_usb_hub_pdevs.o
@@ -18,4 +19,6 @@ endif
obj-$(CONFIG_USB) += usbcore.o
+rust-libs := ./usb
+
obj-$(CONFIG_USB_LEDS_TRIGGER_USBPORT) += ledtrig-usbport.o
diff --git a/drivers/usb/core/usb.rs b/drivers/usb/core/usb.rs
new file mode 100644
index 000000000000..3f7ad02153f5
--- /dev/null
+++ b/drivers/usb/core/usb.rs
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! USB devices and drivers.
+//!
+//! C header: [`include/linux/usb.h`](../../../../include/linux/usb.h)
+
+use kernel::bindings;
+
+/// Check if USB is disabled.
+pub fn disabled() -> bool {
+ // SAFETY: FFI call.
+ unsafe { bindings::usb_disabled() != 0 }
+}
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index b0f74a81c8f9..12116f6fb526 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -30,6 +30,16 @@ config SAMPLE_RUST_PRINT
If unsure, say N.
+config SAMPLE_RUST_USB_SIMPLE
+ tristate "USB simple device driver"
+ help
+ This option builds the Rust USB simple driver sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_usb_simple.
+
+ If unsure, say N.
+
config SAMPLE_RUST_HOSTPROGS
bool "Host programs"
help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..f1ab58a9ecdd 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -2,5 +2,8 @@
obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o
obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_USB_SIMPLE) += rust_usb_simple.o
+
+rust-libs := ../../drivers/usb/core/usb
subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs
diff --git a/samples/rust/rust_usb_simple.rs b/samples/rust/rust_usb_simple.rs
new file mode 100644
index 000000000000..3523f81d5eb8
--- /dev/null
+++ b/samples/rust/rust_usb_simple.rs
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust USB sample.
+
+use kernel::prelude::*;
+
+module! {
+ type: UsbSimple,
+ name: "rust_usb_simple",
+ author: "Martin Rodriguez Reboredo",
+ description: "Rust USB sample",
+ license: "GPL v2",
+}
+
+struct UsbSimple;
+
+impl kernel::Module for UsbSimple {
+ fn init(_module: &'static ThisModule) -> Result<Self> {
+ pr_info!("usb enabled: {}", !usb::disabled());
+ Ok(UsbSimple)
+ }
+}
--
2.42.0
^ permalink raw reply related [flat|nested] 7+ messages in thread