| Message ID | 20200930093559.2120126-1-jean-philippe@linaro.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3effc06a4dde3e2f6ee3d82e59d97ec357802a4b |
| Headers | show |
| Series | [bpf-next] selftests/bpf: Fix alignment of .BTF_ids | expand |
On Wed, Sep 30, 2020 at 11:36:01AM +0200, Jean-Philippe Brucker wrote: > Fix a build failure on arm64, due to missing alignment information for > the .BTF_ids section: > > resolve_btfids.test.o: in function `test_resolve_btfids': > tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140:(.text+0x29c): relocation truncated to fit: R_AARCH64_LDST32_ABS_LO12_NC against `.BTF_ids' > ld: tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140: warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined > > In vmlinux, the .BTF_ids section is aligned to 4 bytes by vmlinux.lds.h. > In test_progs however, .BTF_ids doesn't have alignment constraints. The > arm64 linker expects the btf_id_set.cnt symbol, a u32, to be naturally > aligned but finds it misaligned and cannot apply the relocation. Enforce > alignment of .BTF_ids to 4 bytes. > > Fixes: cd04b04de119 ("selftests/bpf: Add set test to resolve_btfids") > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > --- > tools/testing/selftests/bpf/prog_tests/resolve_btfids.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c > index 8826c652adad..6ace5e9efec1 100644 > --- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c > +++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c > @@ -28,6 +28,12 @@ struct symbol test_symbols[] = { > { "func", BTF_KIND_FUNC, -1 }, > }; > > +/* Align the .BTF_ids section to 4 bytes */ > +asm ( > +".pushsection " BTF_IDS_SECTION " ,\"a\"; \n" > +".balign 4, 0; \n" > +".popsection; \n"); > + Acked-by: Jiri Olsa <jolsa@redhat.com> thanks, jirka > BTF_ID_LIST(test_list_local) > BTF_ID_UNUSED > BTF_ID(typedef, S) > -- > 2.28.0 >
Hello: This patch was applied to bpf/bpf-next.git (refs/heads/master): On Wed, 30 Sep 2020 11:36:01 +0200 you wrote: > Fix a build failure on arm64, due to missing alignment information for > the .BTF_ids section: > > resolve_btfids.test.o: in function `test_resolve_btfids': > tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140:(.text+0x29c): relocation truncated to fit: R_AARCH64_LDST32_ABS_LO12_NC against `.BTF_ids' > ld: tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140: warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined > > [...] Here is the summary with links: - [bpf-next] selftests/bpf: Fix alignment of .BTF_ids https://git.kernel.org/bpf/bpf-next/c/3effc06a4dde You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c index 8826c652adad..6ace5e9efec1 100644 --- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c +++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c @@ -28,6 +28,12 @@ struct symbol test_symbols[] = { { "func", BTF_KIND_FUNC, -1 }, }; +/* Align the .BTF_ids section to 4 bytes */ +asm ( +".pushsection " BTF_IDS_SECTION " ,\"a\"; \n" +".balign 4, 0; \n" +".popsection; \n"); + BTF_ID_LIST(test_list_local) BTF_ID_UNUSED BTF_ID(typedef, S)
Fix a build failure on arm64, due to missing alignment information for the .BTF_ids section: resolve_btfids.test.o: in function `test_resolve_btfids': tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140:(.text+0x29c): relocation truncated to fit: R_AARCH64_LDST32_ABS_LO12_NC against `.BTF_ids' ld: tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140: warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined In vmlinux, the .BTF_ids section is aligned to 4 bytes by vmlinux.lds.h. In test_progs however, .BTF_ids doesn't have alignment constraints. The arm64 linker expects the btf_id_set.cnt symbol, a u32, to be naturally aligned but finds it misaligned and cannot apply the relocation. Enforce alignment of .BTF_ids to 4 bytes. Fixes: cd04b04de119 ("selftests/bpf: Add set test to resolve_btfids") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> --- tools/testing/selftests/bpf/prog_tests/resolve_btfids.c | 6 ++++++ 1 file changed, 6 insertions(+)