Commit 27e88bc4 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

bpf: add find_containing_subprog() utility function 



Add a utility function, looking for a subprogram containing a given
instruction index, rewrite find_subprog() to use this function.

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20241210041100.1898468-2-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 978c4486

kernel/bpf/verifier.c

+24 −4
Original line number Diff line number Diff line
@@ -2597,16 +2597,36 @@ static int cmp_subprogs(const void *a, const void *b) 
	       ((struct bpf_subprog_info *)b)->start;

}









/* Find subprogram that contains instruction at 'off' */









static struct bpf_subprog_info *find_containing_subprog(struct bpf_verifier_env *env, int off)









{









	struct bpf_subprog_info *vals = env->subprog_info;









	int l, r, m;

















	if (off >= env->prog->len || off < 0 || env->subprog_cnt == 0)









		return NULL;

















	l = 0;









	r = env->subprog_cnt - 1;









	while (l < r) {









		m = l + (r - l + 1) / 2;









		if (vals[m].start <= off)









			l = m;









		else









			r = m - 1;









	}









	return &vals[l];









}

















/* Find subprogram that starts exactly at 'off' */









static int find_subprog(struct bpf_verifier_env *env, int off)









{









	struct bpf_subprog_info *p;

















	p = bsearch(&off, env->subprog_info, env->subprog_cnt,









		    sizeof(env->subprog_info[0]), cmp_subprogs);









	if (!p)









	p = find_containing_subprog(env, off);









	if (!p || p->start != off)









		return -ENOENT;









	return p - env->subprog_info;

















}

















static int add_subprog(struct bpf_verifier_env *env, int off)