diff mbox series

[05/18] bpf: Add lnode list node to struct bpf_ksym

Message ID 20200226130345.209469-6-jolsa@kernel.org
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series bpf: Add trampoline and dispatcher to /proc/kallsyms | expand

Commit Message

Jiri Olsa Feb. 26, 2020, 1:03 p.m. UTC 
Adding lnode list node to 'struct bpf_ksym' object,
so the symbol itself can be chained and used in other
objects like bpf_trampoline and bpf_dispatcher.

Changing iterator to bpf_ksym in bpf_get_kallsym.

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

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h |  2 +-
 kernel/bpf/core.c   | 22 +++++++++++-----------
 2 files changed, 12 insertions(+), 12 deletions(-)

Comments

Song Liu Feb. 26, 2020, 10:51 p.m. UTC | #1 
On Wed, Feb 26, 2020 at 5:05 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding lnode list node to 'struct bpf_ksym' object,
> so the symbol itself can be chained and used in other
> objects like bpf_trampoline and bpf_dispatcher.
>
> Changing iterator to bpf_ksym in bpf_get_kallsym.
>
> The ksym->start is holding the prog->bpf_func value,
> so it's ok to use it in bpf_get_kallsym.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Acked-by: Song Liu <songliubraving@fb.com>

nit: I think we should describe this as "move lnode list node to
struct bpf_ksym".
Jiri Olsa Feb. 27, 2020, 8:15 a.m. UTC | #2 
On Wed, Feb 26, 2020 at 02:51:14PM -0800, Song Liu wrote:
> On Wed, Feb 26, 2020 at 5:05 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding lnode list node to 'struct bpf_ksym' object,
> > so the symbol itself can be chained and used in other
> > objects like bpf_trampoline and bpf_dispatcher.
> >
> > Changing iterator to bpf_ksym in bpf_get_kallsym.
> >
> > The ksym->start is holding the prog->bpf_func value,
> > so it's ok to use it in bpf_get_kallsym.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> 
> Acked-by: Song Liu <songliubraving@fb.com>
> 
> nit: I think we should describe this as "move lnode list node to
> struct bpf_ksym".

true, will change

thanks,
jirka
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e7b2e9fc256c..f1174d24c185 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -467,6 +467,7 @@  struct bpf_ksym {
 	unsigned long		 start;
 	unsigned long		 end;
 	char			 name[KSYM_NAME_LEN];
+	struct list_head	 lnode;
 };
 
 enum bpf_tramp_prog_type {
@@ -649,7 +650,6 @@  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;
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index a7aaa81035b1..604093d2153a 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -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;
 }
@@ -612,18 +612,18 @@  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)
@@ -633,8 +633,8 @@  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)
@@ -728,7 +728,7 @@  const struct exception_table_entry *search_bpf_extables(unsigned long addr)
 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;
 
@@ -736,13 +736,13 @@  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;