[PATCH v4] tools build: Fix rust cross compilation
From: Dmitrii Dolgov
Date: Wed Feb 18 2026 - 10:48:12 EST
Currently no target is specified to compile rust code when needed, which
breaks cross compilation. E.g. for arm64:
LD /tmp/build/tests/workloads/perf-test-in.o
aarch64-linux-gnu-ld: /tmp/build/tests/workloads/code_with_type.a(code_with_type.code_with_type.d12f4324cb53c560-cgu.0.rcgu.o): Relocations in generic ELF (EM: 62)
aarch64-linux-gnu-ld: /tmp/build/tests/workloads/code_with_type.a(code_with_type.code_with_type.d12f4324cb53c560-cgu.0.rcgu.o): Relocations in generic ELF (EM: 62)
[...repeated...]
aarch64-linux-gnu-ld: /tmp/build/tests/workloads/code_with_type.a(code_with_type.code_with_type.d12f4324cb53c560-cgu.0.rcgu.o): Relocations in generic ELF (EM: 62)
aarch64-linux-gnu-ld: /tmp/build/tests/workloads/code_with_type.a(code_with_type.code_with_type.d12f4324cb53c560-cgu.0.rcgu.o): Relocations in generic ELF (EM: 62)
aarch64-linux-gnu-ld: /tmp/build/tests/workloads/code_with_type.a: error adding symbols: file in wrong format
make[5]: *** [/perf/tools/build/Makefile.build:162: /tmp/build/tests/workloads/perf-test-in.o] Error 1
make[4]: *** [/perf/tools/build/Makefile.build:156: workloads] Error 2
make[3]: *** [/perf/tools/build/Makefile.build:156: tests] Error 2
make[2]: *** [Makefile.perf:785: /tmp/build/perf-test-in.o] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [Makefile.perf:289: sub-make] Error 2
make: *** [Makefile:76: all] Error 2
Detect required target and pass it via rust_flags to the compiler.
Note that CROSS_COMPILE might be different from what rust compiler
expects, since it may omit the target vendor value, e.g.
"aarch64-linux-gnu" instead of "aarch64-unknown-linux-gnu". Thus
explicitly map supported CROSS_COMPILE values to corresponding Rust
versions, as suggested by Miguel Ojeda.
Tested using arm64 cross-compilation example from [1].
Fixes: 2e05bb52a12 ("perf test workload: Add code_with_type test workload")
Link: https://perfwiki.github.io/main/arm64-cross-compilation-dockerfile/ [1]
Signed-off-by: Dmitrii Dolgov <9erthalion6@xxxxxxxxx>
---
Changes in v4
- Fixed incorrect target name for riscv
Changes in v3
- Improved commit message, add an example of the compilation failure
Changes in v2:
- Map supported CROSS_COMPILE values to corresponding Rust targets
tools/build/Build.include | 9 +++++++++
tools/perf/Makefile.config | 14 ++++++++++++++
tools/perf/Makefile.perf | 2 +-
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/tools/build/Build.include b/tools/build/Build.include
index e45b2eb0d24..cd0baa7a168 100644
--- a/tools/build/Build.include
+++ b/tools/build/Build.include
@@ -98,6 +98,15 @@ c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
c_flags = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
cxx_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
+###
+# Rust flags to be used on rule definition, includes:
+# - global $(RUST_FLAGS)
+# - per target Rust flags
+# - per object Rust flags
+rust_flags_1 = $(RUST_FLAGS) $(RUST_FLAGS_$(basetarget).o) $(RUST_FLAGS_$(obj))
+rust_flags_2 = $(filter-out $(RUST_FLAGS_REMOVE_$(basetarget).o), $(rust_flags_1))
+rust_flags = $(filter-out $(RUST_FLAGS_REMOVE_$(obj)), $(rust_flags_2))
+
###
## HOSTCC C flags
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index a8dc72cfe48..214d8f6d9b8 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -1163,6 +1163,20 @@ ifndef NO_RUST
CFLAGS += -DHAVE_RUST_SUPPORT
$(call detected,CONFIG_RUST_SUPPORT)
endif
+
+ ifneq ($(CROSS_COMPILE),)
+ RUST_TARGET_FLAGS_arm := arm-unknown-linux-gnueabi
+ RUST_TARGET_FLAGS_arm64 := aarch64-unknown-linux-gnu
+ RUST_TARGET_FLAGS_m68k := m68k-unknown-linux-gnu
+ RUST_TARGET_FLAGS_mips := mipsel-unknown-linux-gnu
+ RUST_TARGET_FLAGS_powerpc := powerpc64le-unknown-linux-gnu
+ RUST_TARGET_FLAGS_riscv := riscv64gc-unknown-linux-gnu
+ RUST_TARGET_FLAGS_s390 := s390x-unknown-linux-gnu
+ RUST_TARGET_FLAGS_x86 := x86_64-unknown-linux-gnu
+ RUST_TARGET_FLAGS_x86_64 := x86_64-unknown-linux-gnu
+
+ RUST_FLAGS += --target=$(RUST_TARGET_FLAGS_$(ARCH))
+ endif
endif
# Among the variables below, these:
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 11b63bafdb2..f7b936deeaa 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -274,7 +274,7 @@ ifeq ($(PYLINT),1)
PYLINT := $(shell which pylint 2> /dev/null)
endif
-export srctree OUTPUT RM CC CXX RUSTC LD AR CFLAGS CXXFLAGS V BISON FLEX AWK
+export srctree OUTPUT RM CC CXX RUSTC LD AR CFLAGS CXXFLAGS RUST_FLAGS V BISON FLEX AWK
export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK MYPY PYLINT
include $(srctree)/tools/build/Makefile.include
base-commit: dbf0108347bdb5d4ccef8910555b16c1f1a505f8
--
2.52.0