bpf: Remove prog->active check for bpf_lsm and bpf_iter

The commit 64696c40d03c ("bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline")
removed prog->active check for struct_ops prog.  The bpf_lsm
and bpf_iter is also using trampoline.  Like struct_ops, the bpf_lsm
and bpf_iter have fixed hooks for the prog to attach.  The
kernel does not call the same hook in a recursive way.
This patch also removes the prog->active check for
bpf_lsm and bpf_iter.

A later patch has a test to reproduce the recursion issue
for a sleepable bpf_lsm program.

This patch appends the '_recur' naming to the existing
enter and exit functions that track the prog->active counter.
New __bpf_prog_{enter,exit}[_sleepable] function are
added to skip the prog->active tracking. The '_struct_ops'
version is also removed.

It also moves the decision on picking the enter and exit function to
the new bpf_trampoline_{enter,exit}().  It returns the '_recur' ones
for all tracing progs to use.  For bpf_lsm, bpf_iter,
struct_ops (no prog->active tracking after 64696c40d03c), and
bpf_lsm_cgroup (no prog->active tracking after 69fd337a975c7),
it will return the functions that don't track the prog->active.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 30f76178608b..62f805f427b7 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1649,13 +1649,8 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
 	struct bpf_prog *p = l->link.prog;
 	int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
 
-	if (p->aux->sleepable) {
-		enter_prog = (u64)__bpf_prog_enter_sleepable;
-		exit_prog = (u64)__bpf_prog_exit_sleepable;
-	} else {
-		enter_prog = (u64)__bpf_prog_enter;
-		exit_prog = (u64)__bpf_prog_exit;
-	}
+	enter_prog = (u64)bpf_trampoline_enter(p);
+	exit_prog = (u64)bpf_trampoline_exit(p);
 
 	if (l->cookie == 0) {
 		/* if cookie is zero, one instruction is enough to store it */