[PATCH 15/15] kbuild: Use gendwarfksyms to generate Rust symbol versions
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2024-06-17 17:58:53
Also in:
linux-kbuild, lkml, rust-for-linux
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), rust, the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Miguel Ojeda, Linus Torvalds
Use gendwarfksyms to generate symbol versions for exported Rust symbols, and allow CONFIG_MODVERSIONS to be enabled with CONFIG_RUST, assuming the debugging information needed by gendwarfksyms is also available. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- Makefile | 6 ++++++ init/Kconfig | 2 +- rust/Makefile | 30 ++++++++++++++++++++++++------ 3 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/Makefile b/Makefile
index 14427547dc1e..0701917c5172 100644
--- a/Makefile
+++ b/Makefile@@ -1344,6 +1344,12 @@ prepare: tools/bpf/resolve_btfids endif endif +ifdef CONFIG_MODVERSIONS +ifdef CONFIG_RUST +prepare: tools/gendwarfksyms +endif +endif + PHONY += resolve_btfids_clean resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids
diff --git a/init/Kconfig b/init/Kconfig
index 72404c1f2157..ef29f002e932 100644
--- a/init/Kconfig
+++ b/init/Kconfig@@ -1903,7 +1903,7 @@ config RUST depends on HAVE_RUST depends on RUST_IS_AVAILABLE depends on !CFI_CLANG - depends on !MODVERSIONS + depends on !MODVERSIONS || (DEBUG_INFO && !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT) depends on !GCC_PLUGINS depends on !RANDSTRUCT depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
diff --git a/rust/Makefile b/rust/Makefile
index f70d5e244fee..385cdf5dc320 100644
--- a/rust/Makefile
+++ b/rust/Makefile@@ -356,10 +356,11 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; $(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers.c FORCE $(call if_changed_dep,bindgen) +rust_exports = $(NM) -p --defined-only $(1) | awk '/ (T|R|D) / { printf $(2),$(3) }' + quiet_cmd_exports = EXPORTS $@ cmd_exports = \ - $(NM) -p --defined-only $< \ - | awk '/ (T|R|D) / {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3}' > $@ + $(call rust_exports,$<,"EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3) > $@ $(obj)/exports_core_generated.h: $(obj)/core.o FORCE $(call if_changed,exports)
@@ -420,12 +421,29 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),) __ashlti3 __lshrti3 endif +ifdef CONFIG_MODVERSIONS +# When module versioning is enabled, calculate symbol versions from the DWARF +# debugging information. We can't use a source code parser like genksyms, +# because the source files don't have information about the final structure +# layout and emitted symbols. +gendwarfksyms := $(objtree)/tools/gendwarfksyms/gendwarfksyms + +cmd_gendwarfksyms = \ + $(call rust_exports,$@,"%s %s\n",$$1$(comma)$$3) \ + | $(gendwarfksyms) $@ >> $(dot-target).cmd +endif + +define rule_rustc_library_with_exports + $(call cmd_and_fixdep,rustc_library) + $(call cmd,gendwarfksyms) +endef + $(obj)/core.o: private skip_clippy = 1 $(obj)/core.o: private skip_flags = -Dunreachable_pub $(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym)) $(obj)/core.o: private rustc_target_flags = $(core-cfgs) $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs FORCE - +$(call if_changed_dep,rustc_library) + +$(call if_changed_rule,rustc_library_with_exports) ifdef CONFIG_X86_64 $(obj)/core.o: scripts/target.json endif
@@ -438,7 +456,7 @@ $(obj)/alloc.o: private skip_clippy = 1 $(obj)/alloc.o: private skip_flags = -Dunreachable_pub $(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs) $(obj)/alloc.o: $(RUST_LIB_SRC)/alloc/src/lib.rs $(obj)/compiler_builtins.o FORCE - +$(call if_changed_dep,rustc_library) + +$(call if_changed_rule,rustc_library_with_exports) $(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE +$(call if_changed_dep,rustc_library)
@@ -447,7 +465,7 @@ $(obj)/bindings.o: $(src)/bindings/lib.rs \ $(obj)/compiler_builtins.o \ $(obj)/bindings/bindings_generated.rs \ $(obj)/bindings/bindings_helpers_generated.rs FORCE - +$(call if_changed_dep,rustc_library) + +$(call if_changed_rule,rustc_library_with_exports) $(obj)/uapi.o: $(src)/uapi/lib.rs \ $(obj)/compiler_builtins.o \
@@ -458,6 +476,6 @@ $(obj)/kernel.o: private rustc_target_flags = --extern alloc \ --extern build_error --extern macros --extern bindings --extern uapi $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \ $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE - +$(call if_changed_dep,rustc_library) + +$(call if_changed_rule,rustc_library_with_exports) endif # CONFIG_RUST
--
2.45.2.627.g7a2c4fd464-goog