[PATCH 07/15] bpf: Add bpf_ksym_find function

Jiri Olsa
2020-03-12T19:56:59Z

Adding bpf_ksym_find function that is used bpf bpf address
lookup functions:
__bpf_address_lookup
is_bpf_text_address

while keeping bpf_prog_kallsyms_find to be used only for lookup
of bpf_prog objects (will happen in following changes).

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/core.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index df0caa4bc9cc..6b58c2f1c9c0 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -668,19 +668,27 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
NULL;
}

+static struct bpf_ksym *bpf_ksym_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_ksym, tnode) : NULL;
+}
+
const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
unsigned long *off, char *sym)
{
- struct bpf_prog *prog;
+ struct bpf_ksym *ksym;
char *ret = NULL;

rcu_read_lock();
- prog = bpf_prog_kallsyms_find(addr);
- if (prog) {
- unsigned long symbol_start = prog->aux->ksym.start;
- unsigned long symbol_end = prog->aux->ksym.end;
+ ksym = bpf_ksym_find(addr);
+ if (ksym) {
+ unsigned long symbol_start = ksym->start;
+ unsigned long symbol_end = ksym->end;

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

ret = sym;
if (size)
@@ -698,7 +706,7 @@ bool is_bpf_text_address(unsigned long addr)
bool ret;

rcu_read_lock();
- ret = bpf_prog_kallsyms_find(addr) != NULL;
+ ret = bpf_ksym_find(addr) != NULL;
rcu_read_unlock();

return ret;
--
2.24.1