On Mon, Sep 20, 2021 at 7:15 AM Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> wrote: > > This commit moves BTF ID lookup into the newly added registration > helper, in a way that the bbr, cubic, and dctcp implementation set up > their sets in the bpf_tcp_ca kfunc_btf_set list, while the ones not > dependent on modules are looked up from the wrapper function. > > This lifts the restriction for them to be compiled as built in objects, > and can be loaded as modules if required. Also modify Makefile.modfinal > to resolve_btfids in TCP congestion control modules if the config option > is set, using the base BTF support added in the previous commit. > > See following commits for background on use of: > > CONFIG_X86 ifdef: > 569c484f9995 (bpf: Limit static tcp-cc functions in the .BTF_ids list to x86) > > CONFIG_DYNAMIC_FTRACE ifdef: > 7aae231ac93b (bpf: tcp: Limit calling some tcp cc functions to CONFIG_DYNAMIC_FTRACE) > > [ resolve_btfids uses --no-fail because some crypto kernel modules > under arch/x86/crypto generated from ASM do not have the .BTF sections ] > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> > --- > include/linux/btf.h | 4 ++++ > kernel/bpf/btf.c | 3 +++ > net/ipv4/bpf_tcp_ca.c | 34 +++------------------------------- > net/ipv4/tcp_bbr.c | 28 +++++++++++++++++++++++++++- > net/ipv4/tcp_cubic.c | 26 +++++++++++++++++++++++++- > net/ipv4/tcp_dctcp.c | 26 +++++++++++++++++++++++++- > scripts/Makefile.modfinal | 1 + > 7 files changed, 88 insertions(+), 34 deletions(-) > [...] > diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal > index ff805777431c..b4f83533eda6 100644 > --- a/scripts/Makefile.modfinal > +++ b/scripts/Makefile.modfinal > @@ -41,6 +41,7 @@ quiet_cmd_btf_ko = BTF [M] $@ > cmd_btf_ko = \ > if [ -f vmlinux ]; then \ > LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J --btf_base vmlinux $@; \ > + $(RESOLVE_BTFIDS) --no-fail -s vmlinux $@; \ I think I've asked that before, but I don't remember this being answered. Why is this --no-fail? > else \ > printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ > fi; > -- > 2.33.0 >
