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From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>
Subject: [PATCH bpf-next 6/8] bpf: clean up visit_insn()'s instruction processing
Date: Wed, 1 Mar 2023 21:32:14 -0800	[thread overview]
Message-ID: <20230302053216.1426015-7-andrii@kernel.org> (raw)
In-Reply-To: <20230302053216.1426015-1-andrii@kernel.org>

Instead of referencing processed instruction repeatedly as insns[t]
throughout entire visit_insn() function, take a local insn pointer and
work with it in a cleaner way.

It makes enhancing this function further a bit easier as well.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 kernel/bpf/verifier.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 154f5d251ecb..f8055f3d9b47 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13389,44 +13389,43 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns,
  */
 static int visit_insn(int t, struct bpf_verifier_env *env)
 {
-	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
 	int ret;
 
-	if (bpf_pseudo_func(insns + t))
+	if (bpf_pseudo_func(insn))
 		return visit_func_call_insn(t, insns, env, true);
 
 	/* All non-branch instructions have a single fall-through edge. */
-	if (BPF_CLASS(insns[t].code) != BPF_JMP &&
-	    BPF_CLASS(insns[t].code) != BPF_JMP32)
+	if (BPF_CLASS(insn->code) != BPF_JMP &&
+	    BPF_CLASS(insn->code) != BPF_JMP32)
 		return push_insn(t, t + 1, FALLTHROUGH, env, false);
 
-	switch (BPF_OP(insns[t].code)) {
+	switch (BPF_OP(insn->code)) {
 	case BPF_EXIT:
 		return DONE_EXPLORING;
 
 	case BPF_CALL:
-		if (insns[t].imm == BPF_FUNC_timer_set_callback)
+		if (insn->imm == BPF_FUNC_timer_set_callback)
 			/* Mark this call insn as a prune point to trigger
 			 * is_state_visited() check before call itself is
 			 * processed by __check_func_call(). Otherwise new
 			 * async state will be pushed for further exploration.
 			 */
 			mark_prune_point(env, t);
-		return visit_func_call_insn(t, insns, env,
-					    insns[t].src_reg == BPF_PSEUDO_CALL);
+		return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
 
 	case BPF_JA:
-		if (BPF_SRC(insns[t].code) != BPF_K)
+		if (BPF_SRC(insn->code) != BPF_K)
 			return -EINVAL;
 
 		/* unconditional jump with single edge */
-		ret = push_insn(t, t + insns[t].off + 1, FALLTHROUGH, env,
+		ret = push_insn(t, t + insn->off + 1, FALLTHROUGH, env,
 				true);
 		if (ret)
 			return ret;
 
-		mark_prune_point(env, t + insns[t].off + 1);
-		mark_jmp_point(env, t + insns[t].off + 1);
+		mark_prune_point(env, t + insn->off + 1);
+		mark_jmp_point(env, t + insn->off + 1);
 
 		return ret;
 
@@ -13438,7 +13437,7 @@ static int visit_insn(int t, struct bpf_verifier_env *env)
 		if (ret)
 			return ret;
 
-		return push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
+		return push_insn(t, t + insn->off + 1, BRANCH, env, true);
 	}
 }
 
-- 
2.30.2


  parent reply	other threads:[~2023-03-02  5:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-02  5:32 [PATCH bpf-next 0/8] Misc fixes and preliminaries for iterators Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 1/8] bpf: improve stack slot state printing Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 2/8] bpf: improve regsafe() checks for PTR_TO_{MEM,BUF,TP_BUFFER} Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 3/8] selftests/bpf: enhance align selftest's expected log matching Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 4/8] bpf: honor env->test_state_freq flag in is_state_visited() Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 5/8] selftests/bpf: adjust log_fixup's buffer size for proper truncation Andrii Nakryiko
2023-03-02  5:32 ` Andrii Nakryiko [this message]
2023-03-02  5:32 ` [PATCH bpf-next 7/8] bpf: fix visit_insn()'s detection of BPF_FUNC_timer_set_callback helper Andrii Nakryiko
2023-03-02  5:32 ` [PATCH bpf-next 8/8] bpf: ensure that r0 is marked scratched after any function call Andrii Nakryiko

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