From: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Previously, two things stopped Rust from using MODVERSIONS:
1. Rust symbols are occasionally too long to be represented in the
original versions table
2. Rust types cannot be properly hashed by the existing genksyms
approach because:
* Looking up type definitions in Rust is more complex than C
* Type layout is potentially dependent on the compiler in Rust,
not just the source type declaration.
CONFIG_EXTENDED_MODVERSIONS addresses the first point, and
CONFIG_GENDWARFKSYMS the second. If Rust wants to use MODVERSIONS, allow
it to do so by selecting both features.
Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Co-developed-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
Signed-off-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
---
init/Kconfig | 3 ++-
rust/Makefile | 32 ++++++++++++++++++++++++++++++--
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 530a382ee0feb391b4717abdba3672e584a462d0..f5cce579f29b2ed89e97f8075a3bf70e32e71ad0 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1942,7 +1942,8 @@ config RUST
bool "Rust support"
depends on HAVE_RUST
depends on RUST_IS_AVAILABLE
- depends on !MODVERSIONS
+ select EXTENDED_MODVERSIONS if MODVERSIONS
+ depends on (GENDWARFKSYMS || !MODVERSIONS)
depends on !GCC_PLUGIN_RANDSTRUCT
depends on !RANDSTRUCT
depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
diff --git a/rust/Makefile b/rust/Makefile
index b5e0a73b78f3e58fc8fb8c9fab8fb5792406c6d8..b80bc4eb98202f774c493da89c2caee322cffc91 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -303,10 +303,11 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ;
$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
$(call if_changed_dep,bindgen)
+rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ { printf $(2),$(3) }'
+
quiet_cmd_exports = EXPORTS $@
cmd_exports = \
- $(NM) -p --defined-only $< \
- | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ {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
$(call if_changed,exports)
@@ -378,11 +379,35 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),)
__ashlti3 __lshrti3
endif
+ifdef CONFIG_MODVERSIONS
+cmd_gendwarfksyms = $(if $(skip_gendwarfksyms),, \
+ $(call rust_exports,$@,"%s\n",$$3) | \
+ scripts/gendwarfksyms/gendwarfksyms \
+ $(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes),) \
+ $@ >> $(dot-target).cmd)
+endif
+
define rule_rustc_library
$(call cmd_and_fixdep,rustc_library)
$(call cmd,gen_objtooldep)
+ $(call cmd,gendwarfksyms)
endef
+define rule_rust_cc_library
+ $(call if_changed_rule,cc_o_c)
+ $(call cmd,force_checksrc)
+ $(call cmd,gendwarfksyms)
+endef
+
+# helpers.o uses the same export mechanism as Rust libraries, so ensure symbol
+# versions are calculated for the helpers too.
+$(obj)/helpers/helpers.o: $(src)/helpers/helpers.c $(recordmcount_source) FORCE
+ +$(call if_changed_rule,rust_cc_library)
+
+# Disable symbol versioning for exports.o to avoid conflicts with the actual
+# symbol versions generated from Rust objects.
+$(obj)/exports.o: private skip_gendwarfksyms = 1
+
$(obj)/core.o: private skip_clippy = 1
$(obj)/core.o: private skip_flags = -Wunreachable_pub
$(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))
@@ -394,6 +419,7 @@ ifneq ($(or $(CONFIG_X86_64),$(CONFIG_X86_32)),)
$(obj)/core.o: scripts/target.json
endif
+$(obj)/compiler_builtins.o: private skip_gendwarfksyms = 1
$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
+$(call if_changed_rule,rustc_library)
@@ -404,6 +430,7 @@ $(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_rule,rustc_library)
+$(obj)/build_error.o: private skip_gendwarfksyms = 1
$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
+$(call if_changed_rule,rustc_library)
@@ -413,6 +440,7 @@ $(obj)/bindings.o: $(src)/bindings/lib.rs \
$(obj)/bindings/bindings_helpers_generated.rs FORCE
+$(call if_changed_rule,rustc_library)
+$(obj)/uapi.o: private skip_gendwarfksyms = 1
$(obj)/uapi.o: $(src)/uapi/lib.rs \
$(obj)/compiler_builtins.o \
$(obj)/uapi/uapi_generated.rs FORCE
--
2.47.0.105.g07ac214952-goog
