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authorShahab Vahedi <Shahab.Vahedi@synopsys.com>2022-06-08 14:29:28 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2022-06-09 14:01:21 +0200
commit0b817059a8830b8bc3d50bb2402dea923cd89b01 (patch)
tree651904f88b2af707710d468d44eff4fd051a54cd /tools
parentd352bd889b6a9c9749dadb0e17675795ed9cea9e (diff)
downloadlinux-0b817059a8830b8bc3d50bb2402dea923cd89b01.tar.gz
bpftool: Fix bootstrapping during a cross compilation
This change adjusts the Makefile to use "HOSTAR" as the archive tool
to keep the sanity of the build process for the bootstrap part in
check. For the rationale, please continue reading.

When cross compiling bpftool with buildroot, it leads to an invocation
like:

$ AR="/path/to/buildroot/host/bin/arc-linux-gcc-ar" \
  CC="/path/to/buildroot/host/bin/arc-linux-gcc"    \
  ...
  make

Which in return fails while building the bootstrap section:

----------------------------------8<----------------------------------

  make: Entering directory '/src/bpftool-v6.7.0/src'
  ...                        libbfd: [ on  ]
  ...        disassembler-four-args: [ on  ]
  ...                          zlib: [ on  ]
  ...                        libcap: [ OFF ]
  ...               clang-bpf-co-re: [ on  ] <-- triggers bootstrap

  .
  .
  .

    LINK     /src/bpftool-v6.7.0/src/bootstrap/bpftool
  /usr/bin/ld: /src/bpftool-v6.7.0/src/bootstrap/libbpf/libbpf.a:
               error adding symbols: archive has no index; run ranlib
               to add one
  collect2: error: ld returned 1 exit status
  make: *** [Makefile:211: /src/bpftool-v6.7.0/src/bootstrap/bpftool]
            Error 1
  make: *** Waiting for unfinished jobs....
    AR       /src/bpftool-v6.7.0/src/libbpf/libbpf.a
    make[1]: Leaving directory '/src/bpftool-v6.7.0/libbpf/src'
    make: Leaving directory '/src/bpftool-v6.7.0/src'

---------------------------------->8----------------------------------

This occurs because setting "AR" confuses the build process for the
bootstrap section and it calls "arc-linux-gcc-ar" to create and index
"libbpf.a" instead of the host "ar".

Signed-off-by: Shahab Vahedi <shahab@synopsys.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/bpf/8d297f0c-cfd0-ef6f-3970-6dddb3d9a87a@synopsys.com
Diffstat (limited to 'tools')
-rw-r--r--tools/bpf/bpftool/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index c6d2c77d0252..c19e0e4c41bd 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -53,7 +53,7 @@ $(LIBBPF_INTERNAL_HDRS): $(LIBBPF_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_HDRS_
 $(LIBBPF_BOOTSTRAP): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_BOOTSTRAP_OUTPUT)
 	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \
 		DESTDIR=$(LIBBPF_BOOTSTRAP_DESTDIR:/=) prefix= \
-		ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) $@ install_headers
+		ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) AR=$(HOSTAR) $@ install_headers
 
 $(LIBBPF_BOOTSTRAP_INTERNAL_HDRS): $(LIBBPF_BOOTSTRAP_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_BOOTSTRAP_HDRS_DIR)
 	$(call QUIET_INSTALL, $@)