Commit ecb60d1c authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

bpf: Move lnode list node to struct bpf_ksym 



Adding lnode list node to 'struct bpf_ksym' object,
so the struct bpf_ksym itself can be chained and used
in other objects like bpf_trampoline and bpf_dispatcher.

Changing iterator to bpf_ksym in bpf_get_kallsym function.

The ksym->start is holding the prog->bpf_func value,
so it's ok to use it as value in bpf_get_kallsym.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200312195610.346362-6-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent bfea9a85

include/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -476,6 +476,7 @@ struct bpf_ksym { 
	unsigned long		 start;

	unsigned long		 end;

	char			 name[KSYM_NAME_LEN];

	struct list_head	 lnode;

};



enum bpf_tramp_prog_type {
@@ -659,7 +660,6 @@ struct bpf_prog_aux { 
	struct bpf_jit_poke_descriptor *poke_tab;

	u32 size_poke_tab;

	struct latch_tree_node ksym_tnode;

	struct list_head ksym_lnode;

	struct bpf_ksym ksym;

	const struct bpf_prog_ops *ops;

	struct bpf_map **used_maps;

kernel/bpf/core.c

+11 −11
Original line number Diff line number Diff line
@@ -97,7 +97,7 @@ struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flag 
	fp->aux->prog = fp;

	fp->jit_requested = ebpf_jit_enabled();



	INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);

	INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);



	return fp;

}
@@ -613,18 +613,18 @@ static struct latch_tree_root bpf_tree __cacheline_aligned; 


static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)

{

	WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));

	list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);

	WARN_ON_ONCE(!list_empty(&aux->ksym.lnode));

	list_add_tail_rcu(&aux->ksym.lnode, &bpf_kallsyms);

	latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);

}



static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)

{

	if (list_empty(&aux->ksym_lnode))

	if (list_empty(&aux->ksym.lnode))

		return;



	latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);

	list_del_rcu(&aux->ksym_lnode);

	list_del_rcu(&aux->ksym.lnode);

}



static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
@@ -634,8 +634,8 @@ static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 


static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)

{

	return list_empty(&fp->aux->ksym_lnode) ||

	       fp->aux->ksym_lnode.prev == LIST_POISON2;

	return list_empty(&fp->aux->ksym.lnode) ||

	       fp->aux->ksym.lnode.prev == LIST_POISON2;

}



void bpf_prog_kallsyms_add(struct bpf_prog *fp)
@@ -729,7 +729,7 @@ out: 
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,

		    char *sym)

{

	struct bpf_prog_aux *aux;

	struct bpf_ksym *ksym;

	unsigned int it = 0;

	int ret = -ERANGE;
@@ -737,13 +737,13 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 
		return ret;



	rcu_read_lock();

	list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {

	list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {

		if (it++ != symnum)

			continue;



		strncpy(sym, aux->ksym.name, KSYM_NAME_LEN);

		strncpy(sym, ksym->name, KSYM_NAME_LEN);



		*value = (unsigned long)aux->prog->bpf_func;

		*value = ksym->start;

		*type  = BPF_SYM_ELF_TYPE;



		ret = 0;

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