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[116.14.181.187]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f6d859ea3csm61578855ad.178.2024.06.10.05.42.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jun 2024 05:42:38 -0700 (PDT) From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yonghong.song@linux.dev, hffilwlqm@gmail.com, kernel-patches-bot@fb.com Subject: [PATCH v2 bpf-next 2/2] bpf, x64: Remove tail call detection Date: Mon, 10 Jun 2024 20:42:24 +0800 Message-ID: <20240610124224.34673-3-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240610124224.34673-1-hffilwlqm@gmail.com> References: <20240610124224.34673-1-hffilwlqm@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net As 'prog->aux->tail_call_reachable' is correct for tail call present, it's unnecessary to detect tail call in x86 jit. Therefore, let's remove it. Signed-off-by: Leon Hwang --- arch/x86/net/bpf_jit_comp.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 5159c7a229229..7c130001fbfe7 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1234,13 +1234,11 @@ bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) } static void detect_reg_usage(struct bpf_insn *insn, int insn_cnt, - bool *regs_used, bool *tail_call_seen) + bool *regs_used) { int i; for (i = 1; i <= insn_cnt; i++, insn++) { - if (insn->code == (BPF_JMP | BPF_TAIL_CALL)) - *tail_call_seen = true; if (insn->dst_reg == BPF_REG_6 || insn->src_reg == BPF_REG_6) regs_used[0] = true; if (insn->dst_reg == BPF_REG_7 || insn->src_reg == BPF_REG_7) @@ -1324,7 +1322,6 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image struct bpf_insn *insn = bpf_prog->insnsi; bool callee_regs_used[4] = {}; int insn_cnt = bpf_prog->len; - bool tail_call_seen = false; bool seen_exit = false; u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY]; u64 arena_vm_start, user_vm_start; @@ -1336,11 +1333,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image arena_vm_start = bpf_arena_get_kern_vm_start(bpf_prog->aux->arena); user_vm_start = bpf_arena_get_user_vm_start(bpf_prog->aux->arena); - detect_reg_usage(insn, insn_cnt, callee_regs_used, - &tail_call_seen); - - /* tail call's presence in current prog implies it is reachable */ - tail_call_reachable |= tail_call_seen; + detect_reg_usage(insn, insn_cnt, callee_regs_used); emit_prologue(&prog, bpf_prog->aux->stack_depth, bpf_prog_was_classic(bpf_prog), tail_call_reachable,