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authorJiri Olsa <jolsa@kernel.org>2024-04-30 13:28:26 +0200
committerAndrii Nakryiko <andrii@kernel.org>2024-04-30 09:45:53 -0700
commit5c919acef85147886eb2abf86fb147f94680a8b0 (patch)
tree045b9f1176ff8ddecdf9fe1b31f2b7e19aa4aa16 /kernel/bpf
parentadf46d88ae4b2557f7e2e02547a25fb866935711 (diff)
bpf: Add support for kprobe session cookie
Adding support for cookie within the session of kprobe multi entry and return program. The session cookie is u64 value and can be retrieved be new kfunc bpf_session_cookie, which returns pointer to the cookie value. The bpf program can use the pointer to store (on entry) and load (on return) the value. The cookie value is implemented via fprobe feature that allows to share values between entry and return ftrace fprobe callbacks. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240430112830.1184228-4-jolsa@kernel.org
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/verifier.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5d42db05315e..7360f04f9ec7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11063,6 +11063,7 @@ enum special_kfunc_type {
KF_bpf_preempt_disable,
KF_bpf_preempt_enable,
KF_bpf_iter_css_task_new,
+ KF_bpf_session_cookie,
};
BTF_SET_START(special_kfunc_set)
@@ -11123,6 +11124,7 @@ BTF_ID(func, bpf_iter_css_task_new)
#else
BTF_ID_UNUSED
#endif
+BTF_ID(func, bpf_session_cookie)
static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
{
@@ -12294,6 +12296,11 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
}
}
+ if (meta.func_id == special_kfunc_list[KF_bpf_session_cookie]) {
+ meta.r0_size = sizeof(u64);
+ meta.r0_rdonly = false;
+ }
+
if (is_bpf_wq_set_callback_impl_kfunc(meta.func_id)) {
err = push_callback_call(env, insn, insn_idx, meta.subprogno,
set_timer_callback_state);