| Message ID | 20210920141526.3940002-6-memxor@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Support kernel module function calls from eBPF | expand |
On Mon, Sep 20, 2021 at 7:15 AM Kumar Kartikeya Dwivedi <memxor@gmail.com> 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@gmail.com> > --- > 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 >
On Wed, Sep 22, 2021 at 03:48:55AM IST, Andrii Nakryiko wrote: > On Mon, Sep 20, 2021 at 7:15 AM Kumar Kartikeya Dwivedi > <memxor@gmail.com> 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@gmail.com> > > --- > > 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? > Sorry, the first time, I missed that mail, and then it was too late so I decided to put the reason in the commit message above. > > [ resolve_btfids uses --no-fail because some crypto kernel modules > > under arch/x86/crypto generated from ASM do not have the .BTF sections ] I could add a mode that fails only when processing a .BTF section present in object fails, would that be better? -- Kartikeya
On Tue, Sep 21, 2021 at 3:23 PM Kumar Kartikeya Dwivedi <memxor@gmail.com> wrote: > > On Wed, Sep 22, 2021 at 03:48:55AM IST, Andrii Nakryiko wrote: > > On Mon, Sep 20, 2021 at 7:15 AM Kumar Kartikeya Dwivedi > > <memxor@gmail.com> 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@gmail.com> > > > --- > > > 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? > > > > Sorry, the first time, I missed that mail, and then it was too late so I decided > to put the reason in the commit message above. > > > > [ resolve_btfids uses --no-fail because some crypto kernel modules > > > under arch/x86/crypto generated from ASM do not have the .BTF sections ] > > I could add a mode that fails only when processing a .BTF section present in > object fails, would that be better? Oh, missed [ ] part in the commit message. But yeah, it feels like it shouldn't be an error if the module legitimately doesn't have a .BTF section. Is it an error right now? cc Jiri, maybe that was intentional > > -- > Kartikeya
diff --git a/include/linux/btf.h b/include/linux/btf.h index 7884983857d9..f5ae81e225be 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -269,4 +269,8 @@ static inline void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l, struct kfunc_btf_id_set name = { LIST_HEAD_INIT(name.list), (set), \ THIS_MODULE } +extern struct kfunc_btf_id_list bpf_tcp_ca_kfunc_list; + +DECLARE_CHECK_KFUNC_CALLBACK(bpf_tcp_ca); + #endif diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index d17f45b163f5..671b4f713a51 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6394,3 +6394,6 @@ EXPORT_SYMBOL_GPL(unregister_kfunc_btf_id_set); mutex_unlock(&list_name.mutex); \ return false; \ } + +DEFINE_KFUNC_BTF_ID_LIST(bpf_tcp_ca_kfunc_list); +DEFINE_CHECK_KFUNC_CALLBACK(bpf_tcp_ca, bpf_tcp_ca_kfunc_list); diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index b3afd3361f34..c9f1d2dcf67b 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -223,41 +223,13 @@ BTF_ID(func, tcp_reno_cong_avoid) BTF_ID(func, tcp_reno_undo_cwnd) BTF_ID(func, tcp_slow_start) BTF_ID(func, tcp_cong_avoid_ai) -#ifdef CONFIG_X86 -#ifdef CONFIG_DYNAMIC_FTRACE -#if IS_BUILTIN(CONFIG_TCP_CONG_CUBIC) -BTF_ID(func, cubictcp_init) -BTF_ID(func, cubictcp_recalc_ssthresh) -BTF_ID(func, cubictcp_cong_avoid) -BTF_ID(func, cubictcp_state) -BTF_ID(func, cubictcp_cwnd_event) -BTF_ID(func, cubictcp_acked) -#endif -#if IS_BUILTIN(CONFIG_TCP_CONG_DCTCP) -BTF_ID(func, dctcp_init) -BTF_ID(func, dctcp_update_alpha) -BTF_ID(func, dctcp_cwnd_event) -BTF_ID(func, dctcp_ssthresh) -BTF_ID(func, dctcp_cwnd_undo) -BTF_ID(func, dctcp_state) -#endif -#if IS_BUILTIN(CONFIG_TCP_CONG_BBR) -BTF_ID(func, bbr_init) -BTF_ID(func, bbr_main) -BTF_ID(func, bbr_sndbuf_expand) -BTF_ID(func, bbr_undo_cwnd) -BTF_ID(func, bbr_cwnd_event) -BTF_ID(func, bbr_ssthresh) -BTF_ID(func, bbr_min_tso_segs) -BTF_ID(func, bbr_set_state) -#endif -#endif /* CONFIG_DYNAMIC_FTRACE */ -#endif /* CONFIG_X86 */ BTF_SET_END(bpf_tcp_ca_kfunc_ids) static bool bpf_tcp_ca_check_kfunc_call(u32 kfunc_btf_id, struct module *owner) { - return btf_id_set_contains(&bpf_tcp_ca_kfunc_ids, kfunc_btf_id); + if (btf_id_set_contains(&bpf_tcp_ca_kfunc_ids, kfunc_btf_id)) + return true; + return __bpf_check_bpf_tcp_ca_kfunc_call(kfunc_btf_id, owner); } static const struct bpf_verifier_ops bpf_tcp_ca_verifier_ops = { diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index 6274462b86b4..ec5550089b4d 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -56,6 +56,8 @@ * otherwise TCP stack falls back to an internal pacing using one high * resolution timer per TCP socket and may use more resources. */ +#include <linux/btf.h> +#include <linux/btf_ids.h> #include <linux/module.h> #include <net/tcp.h> #include <linux/inet_diag.h> @@ -1152,14 +1154,38 @@ static struct tcp_congestion_ops tcp_bbr_cong_ops __read_mostly = { .set_state = bbr_set_state, }; +BTF_SET_START(tcp_bbr_kfunc_ids) +#ifdef CONFIG_X86 +#ifdef CONFIG_DYNAMIC_FTRACE +BTF_ID(func, bbr_init) +BTF_ID(func, bbr_main) +BTF_ID(func, bbr_sndbuf_expand) +BTF_ID(func, bbr_undo_cwnd) +BTF_ID(func, bbr_cwnd_event) +BTF_ID(func, bbr_ssthresh) +BTF_ID(func, bbr_min_tso_segs) +BTF_ID(func, bbr_set_state) +#endif +#endif +BTF_SET_END(tcp_bbr_kfunc_ids) + +static DEFINE_KFUNC_BTF_ID_SET(&tcp_bbr_kfunc_ids, tcp_bbr_kfunc_btf_set); + static int __init bbr_register(void) { + int ret; + BUILD_BUG_ON(sizeof(struct bbr) > ICSK_CA_PRIV_SIZE); - return tcp_register_congestion_control(&tcp_bbr_cong_ops); + ret = tcp_register_congestion_control(&tcp_bbr_cong_ops); + if (ret) + return ret; + register_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_bbr_kfunc_btf_set); + return 0; } static void __exit bbr_unregister(void) { + unregister_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_bbr_kfunc_btf_set); tcp_unregister_congestion_control(&tcp_bbr_cong_ops); } diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 4a30deaa9a37..5e9d9c51164c 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -25,6 +25,8 @@ */ #include <linux/mm.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> #include <linux/module.h> #include <linux/math64.h> #include <net/tcp.h> @@ -482,8 +484,25 @@ static struct tcp_congestion_ops cubictcp __read_mostly = { .name = "cubic", }; +BTF_SET_START(tcp_cubic_kfunc_ids) +#ifdef CONFIG_X86 +#ifdef CONFIG_DYNAMIC_FTRACE +BTF_ID(func, cubictcp_init) +BTF_ID(func, cubictcp_recalc_ssthresh) +BTF_ID(func, cubictcp_cong_avoid) +BTF_ID(func, cubictcp_state) +BTF_ID(func, cubictcp_cwnd_event) +BTF_ID(func, cubictcp_acked) +#endif +#endif +BTF_SET_END(tcp_cubic_kfunc_ids) + +static DEFINE_KFUNC_BTF_ID_SET(&tcp_cubic_kfunc_ids, tcp_cubic_kfunc_btf_set); + static int __init cubictcp_register(void) { + int ret; + BUILD_BUG_ON(sizeof(struct bictcp) > ICSK_CA_PRIV_SIZE); /* Precompute a bunch of the scaling factors that are used per-packet @@ -514,11 +533,16 @@ static int __init cubictcp_register(void) /* divide by bic_scale and by constant Srtt (100ms) */ do_div(cube_factor, bic_scale * 10); - return tcp_register_congestion_control(&cubictcp); + ret = tcp_register_congestion_control(&cubictcp); + if (ret) + return ret; + register_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_cubic_kfunc_btf_set); + return 0; } static void __exit cubictcp_unregister(void) { + unregister_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_cubic_kfunc_btf_set); tcp_unregister_congestion_control(&cubictcp); } diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c index 79f705450c16..0d7ab3cc7b61 100644 --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -36,6 +36,8 @@ * Glenn Judd <glenn.judd@morganstanley.com> */ +#include <linux/btf.h> +#include <linux/btf_ids.h> #include <linux/module.h> #include <linux/mm.h> #include <net/tcp.h> @@ -236,14 +238,36 @@ static struct tcp_congestion_ops dctcp_reno __read_mostly = { .name = "dctcp-reno", }; +BTF_SET_START(tcp_dctcp_kfunc_ids) +#ifdef CONFIG_X86 +#ifdef CONFIG_DYNAMIC_FTRACE +BTF_ID(func, dctcp_init) +BTF_ID(func, dctcp_update_alpha) +BTF_ID(func, dctcp_cwnd_event) +BTF_ID(func, dctcp_ssthresh) +BTF_ID(func, dctcp_cwnd_undo) +BTF_ID(func, dctcp_state) +#endif +#endif +BTF_SET_END(tcp_dctcp_kfunc_ids) + +static DEFINE_KFUNC_BTF_ID_SET(&tcp_dctcp_kfunc_ids, tcp_dctcp_kfunc_btf_set); + static int __init dctcp_register(void) { + int ret; + BUILD_BUG_ON(sizeof(struct dctcp) > ICSK_CA_PRIV_SIZE); - return tcp_register_congestion_control(&dctcp); + ret = tcp_register_congestion_control(&dctcp); + if (ret) + return ret; + register_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_dctcp_kfunc_btf_set); + return 0; } static void __exit dctcp_unregister(void) { + unregister_kfunc_btf_id_set(&bpf_tcp_ca_kfunc_list, &tcp_dctcp_kfunc_btf_set); tcp_unregister_congestion_control(&dctcp); } 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 $@; \ else \ printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ fi;
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@gmail.com> --- 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(-)