Commit c941ce9c authored by Quentin Monnet's avatar Quentin Monnet Committed by Daniel Borkmann
Browse files

bpf: add verifier callback to get stack usage info for offloaded progs 



In preparation for BPF-to-BPF calls in offloaded programs, add a new
function attribute to the struct bpf_prog_offload_ops so that drivers
supporting eBPF offload can hook at the end of program verification, and
potentially extract information collected by the verifier.

Implement a minimal callback (returning 0) in the drivers providing the
structs, namely netdevsim and nfp.

This will be useful in the nfp driver, in later commits, to extract the
number of subprograms as well as the stack depth for those subprograms.

Signed-off-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: default avatarJiong Wang <jiong.wang@netronome.com>
Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 31ce8c4a

drivers/net/ethernet/netronome/nfp/bpf/verifier.c

+7 −1
Original line number Diff line number Diff line
@@ -640,6 +640,12 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx) 
	return 0;

}



static int nfp_bpf_finalize(struct bpf_verifier_env *env)

{

	return 0;

}



const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops = {

	.insn_hook	= nfp_verify_insn,

	.finalize	= nfp_bpf_finalize,

};

drivers/net/netdevsim/bpf.c

+7 −1
Original line number Diff line number Diff line
@@ -86,8 +86,14 @@ nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn) 
	return 0;

}



static int nsim_bpf_finalize(struct bpf_verifier_env *env)

{

	return 0;

}



static const struct bpf_prog_offload_ops nsim_bpf_analyzer_ops = {

	.insn_hook	= nsim_bpf_verify_insn,

	.finalize	= nsim_bpf_finalize,

};



static bool nsim_xdp_offload_active(struct netdevsim *ns)

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -263,6 +263,7 @@ struct bpf_verifier_ops { 
struct bpf_prog_offload_ops {

	int (*insn_hook)(struct bpf_verifier_env *env,

			 int insn_idx, int prev_insn_idx);

	int (*finalize)(struct bpf_verifier_env *env);

};



struct bpf_prog_offload {

include/linux/bpf_verifier.h

+1 −0
Original line number Diff line number Diff line
@@ -245,5 +245,6 @@ static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env) 
int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env);

int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,

				 int insn_idx, int prev_insn_idx);

int bpf_prog_offload_finalize(struct bpf_verifier_env *env);



#endif /* _LINUX_BPF_VERIFIER_H */

kernel/bpf/offload.c

+18 −0
Original line number Diff line number Diff line
@@ -172,6 +172,24 @@ int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, 
	return ret;

}



int bpf_prog_offload_finalize(struct bpf_verifier_env *env)

{

	struct bpf_prog_offload *offload;

	int ret = -ENODEV;



	down_read(&bpf_devs_lock);

	offload = env->prog->aux->offload;

	if (offload) {

		if (offload->dev_ops->finalize)

			ret = offload->dev_ops->finalize(env);

		else

			ret = 0;

	}

	up_read(&bpf_devs_lock);



	return ret;

}



static void __bpf_prog_offload_destroy(struct bpf_prog *prog)

{

	struct bpf_prog_offload *offload = prog->aux->offload;

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