From 88fd9e5352fe05f7fe57778293aebd4cd106960b Mon Sep 17 00:00:00 2001 From: KP Singh Date: Wed, 4 Mar 2020 20:18:47 +0100 Subject: bpf: Refactor trampoline update code As we need to introduce a third type of attachment for trampolines, the flattened signature of arch_prepare_bpf_trampoline gets even more complicated. Refactor the prog and count argument to arch_prepare_bpf_trampoline to use bpf_tramp_progs to simplify the addition and accounting for new attachment types. Signed-off-by: KP Singh Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200304191853.1529-2-kpsingh@chromium.org --- include/linux/bpf.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f13c78c6f29d..98ec10b23dbb 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -433,6 +433,16 @@ struct btf_func_model { */ #define BPF_TRAMP_F_SKIP_FRAME BIT(2) +/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50 + * bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2 + */ +#define BPF_MAX_TRAMP_PROGS 40 + +struct bpf_tramp_progs { + struct bpf_prog *progs[BPF_MAX_TRAMP_PROGS]; + int nr_progs; +}; + /* Different use cases for BPF trampoline: * 1. replace nop at the function entry (kprobe equivalent) * flags = BPF_TRAMP_F_RESTORE_REGS @@ -455,8 +465,7 @@ struct btf_func_model { */ int arch_prepare_bpf_trampoline(void *image, void *image_end, const struct btf_func_model *m, u32 flags, - struct bpf_prog **fentry_progs, int fentry_cnt, - struct bpf_prog **fexit_progs, int fexit_cnt, + struct bpf_tramp_progs *tprogs, void *orig_call); /* these two functions are called from generated trampoline */ u64 notrace __bpf_prog_enter(void); -- cgit v1.2.3