[PATCH v4 3/4] tools/build: Allow versioning LLVM readelf
From: James Clark
Date: Wed Jul 15 2026 - 11:39:52 EST
Documentation/kbuild/llvm.rst mentions that readelf is included in the
LLVM toolchain, but it's not currently included in this block.
Add it so that LLVM=... options also apply to readelf. Users in tools/
were Perf which was hardcoding it, and another was the BPF makefile.
Both already include Makefile.include so convert them to use the new
variables.
Where readelf wasn't doing anything arch specific, use HOSTREADELF
because it's more likely to be installed.
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
tools/lib/bpf/Makefile | 8 ++++----
tools/perf/Makefile.perf | 1 -
tools/scripts/Makefile.include | 4 ++++
3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index eca584fb061e16013e76827e4203f6be0477a73e..269fe21fc8da73083367b3c122bdd2b718e12bc5 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -115,12 +115,12 @@ PC_FILE := $(addprefix $(OUTPUT),$(PC_FILE))
TAGS_PROG := $(if $(shell which etags 2>/dev/null),etags,ctags)
-GLOBAL_SYM_COUNT = $(shell readelf -s --wide $(BPF_IN_SHARED) | \
+GLOBAL_SYM_COUNT = $(shell $(HOSTREADELF) -s --wide $(BPF_IN_SHARED) | \
cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' | \
sed 's/\[.*\]//' | \
awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \
sort -u | wc -l)
-VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \
+VERSIONED_SYM_COUNT = $(shell $(HOSTREADELF) --dyn-syms --wide $(OUTPUT)libbpf.so | \
sed 's/\[.*\]//' | \
awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \
grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l)
@@ -183,12 +183,12 @@ check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
"versioned symbols in $^ ($(VERSIONED_SYM_COUNT))." \
"Please make sure all LIBBPF_API symbols are" \
"versioned in $(VERSION_SCRIPT)." >&2; \
- readelf -s --wide $(BPF_IN_SHARED) | \
+ $(HOSTREADELF) -s --wide $(BPF_IN_SHARED) | \
cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' | \
sed 's/\[.*\]//' | \
awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \
sort -u > $(OUTPUT)libbpf_global_syms.tmp; \
- readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \
+ $(HOSTREADELF) --dyn-syms --wide $(OUTPUT)libbpf.so | \
sed 's/\[.*\]//' | \
awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}'| \
grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | \
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 476b8dcaef58cb1f3fa75f46a647c2cfe2352767..4d0d7ae02e06b117487a17691c4e62a138428ac5 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -215,7 +215,6 @@ FLEX ?= flex
BISON ?= bison
STRIP = strip
AWK = awk
-READELF ?= readelf
# include Makefile.config by default and rule out
# non-config cases
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index e81e5b479c563321e458b2a7ad8fca2b4607a254..46a3872b87624a7bf475d9b42a3e471f36789dfd 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -73,6 +73,8 @@ ifneq ($(LLVM),)
$(call allow-override,LLC,$(LLVM_PREFIX)llc$(LLVM_SUFFIX))
$(call allow-override,LLVM_CONFIG,$(LLVM_PREFIX)llvm-config$(LLVM_SUFFIX))
$(call allow-override,LLVM_OBJCOPY,$(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX))
+ $(call allow-override,READELF,$(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX))
+ $(call allow-override,HOSTREADELF,$(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX))
else
# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
$(call allow-override,CC,$(CROSS_COMPILE)gcc)
@@ -80,11 +82,13 @@ else
$(call allow-override,LD,$(CROSS_COMPILE)ld)
$(call allow-override,CXX,$(CROSS_COMPILE)g++)
$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
+ $(call allow-override,READELF,$(CROSS_COMPILE)readelf)
# Host versions aren't prefixed
$(call allow-override,HOSTAR,ar)
$(call allow-override,HOSTCC,gcc)
$(call allow-override,HOSTLD,ld)
+ $(call allow-override,HOSTREADELF,readelf)
# Some tools still require Clang, LLC and/or LLVM utils
$(call allow-override,CLANG,clang)
--
2.34.1