Commit cbd76f8d authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

bpf: Add prog flag to struct bpf_ksym object 



Adding 'prog' bool flag to 'struct bpf_ksym' to mark that
this object belongs to bpf_prog object.

This change allows having bpf_prog objects together with
other types (trampolines and dispatchers) in the single
bpf_tree. It's used when searching for bpf_prog exception
tables by the bpf_prog_ksym_find function, where we need
to get the bpf_prog pointer.

>From now we can safely add bpf_ksym support for trampoline
or dispatcher objects, because we can differentiate them
from bpf_prog objects.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200312195610.346362-9-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent eda0c929

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -478,6 +478,7 @@ struct bpf_ksym { 
	char			 name[KSYM_NAME_LEN];

	struct list_head	 lnode;

	struct latch_tree_node	 tnode;

	bool			 prog;

};



enum bpf_tramp_prog_type {

kernel/bpf/core.c

+11 −11
Original line number Diff line number Diff line
@@ -642,6 +642,7 @@ void bpf_prog_kallsyms_add(struct bpf_prog *fp) 


	bpf_prog_ksym_set_addr(fp);

	bpf_prog_ksym_set_name(fp);

	fp->aux->ksym.prog = true;



	spin_lock_bh(&bpf_lock);

	bpf_prog_ksym_node_add(fp->aux);
@@ -658,16 +659,6 @@ void bpf_prog_kallsyms_del(struct bpf_prog *fp) 
	spin_unlock_bh(&bpf_lock);

}



static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)

{

	struct latch_tree_node *n;



	n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);

	return n ?

	       container_of(n, struct bpf_prog_aux, ksym.tnode)->prog :

	       NULL;

}



static struct bpf_ksym *bpf_ksym_find(unsigned long addr)

{

	struct latch_tree_node *n;
@@ -712,13 +703,22 @@ bool is_bpf_text_address(unsigned long addr) 
	return ret;

}



static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)

{

	struct bpf_ksym *ksym = bpf_ksym_find(addr);



	return ksym && ksym->prog ?

	       container_of(ksym, struct bpf_prog_aux, ksym)->prog :

	       NULL;

}



const struct exception_table_entry *search_bpf_extables(unsigned long addr)

{

	const struct exception_table_entry *e = NULL;

	struct bpf_prog *prog;



	rcu_read_lock();

	prog = bpf_prog_kallsyms_find(addr);

	prog = bpf_prog_ksym_find(addr);

	if (!prog)

		goto out;

	if (!prog->aux->num_exentries)

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