From patchwork Sat Jan 26 17:26:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiong Wang X-Patchwork-Id: 1031476 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=netronome.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="jeK5A5IO"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43n2r32B2vz9s7h for ; Sun, 27 Jan 2019 04:26:43 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726291AbfAZR0Y (ORCPT ); Sat, 26 Jan 2019 12:26:24 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:54165 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726089AbfAZR0Y (ORCPT ); Sat, 26 Jan 2019 12:26:24 -0500 Received: by mail-wm1-f67.google.com with SMTP id d15so9650236wmb.3 for ; Sat, 26 Jan 2019 09:26:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=EJQP/vrZDdzlT17Gt5cjzNj8GSxGKxcs+GqQGramIAs=; b=jeK5A5IOZVQyHWtJEqrKkXutm2PUA4kLa4r/fDORVXyDAXToGLl41Kxm8qezt7gIcy eiRXfsWkSqr8mI8MtsgWODo5fE+zQ8h8rYGjxHJK89hS6mOFxv806/EEG6Rl0N+mPI/4 gir6KAcShDjjdV9U81o7xK67I8fx6PkUAWX5ncGc83/LI2rH968W1tkY9k5HdaE2PksB h5cYgg/ayZGLlz8N/0RrA3Oponf7S9DN7Tj1PqDaPtG2DIczTuxCulZ4MTmMhGV9c3/C nJ8f+3Y8j9+qils8oZ212es6sB35ZSuzWibRLy1N3RTDO+AExOCJXVu1ElEbkVD+zvv1 rMNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=EJQP/vrZDdzlT17Gt5cjzNj8GSxGKxcs+GqQGramIAs=; b=hIe2xMe9NUD1Hj/Q/cyo+K9rgE9Ncy3soNKdXexm5yOYFqB/myJLnIZ2CvlwY40jd4 KYrHBjQbZISMqsRD+HRpIotGPj7+9QeyWq2lasyCdOrOXPgl29RAKn96yUUjSKYeO4No PVVan+YrsY+A+5pvoE2r8IzOPzTTsBQFxF1QWO7jWOvbScx+okKJfvvqDZLRvRyv+OD2 l7MFcNMgV/8ZrIfN4nYQTn4esLhToK6Z8JEh0qO4kcqVC/J2C2iyRvYR6S7qDV9glM+j bD5/mUraVrubUqLncAbsKsa8R2s+PlmI66e4Z9iCTTotGHCfs3tdu+bJtf1hQ2yc2/Us S7tA== X-Gm-Message-State: AJcUukeIcY0pxCxUMg+aGFg5e5JrhZURHy7t5LAXdDFCXKF4Lm0u8JOf JDn2hwNK5ExZjT/Z1U9IyJIGCw== X-Google-Smtp-Source: ALg8bN6UQ1jrQ2dHkMfA66jWI98mDKWxslrdDOi7Dqq02D3GNxg0Ur35mPBMSXhhE/M14YZWiooUEw== X-Received: by 2002:a1c:85d2:: with SMTP id h201mr10442653wmd.151.1548523581584; Sat, 26 Jan 2019 09:26:21 -0800 (PST) Received: from cbtest28.netronome.com ([217.38.71.146]) by smtp.gmail.com with ESMTPSA id g188sm84426444wmf.32.2019.01.26.09.26.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 26 Jan 2019 09:26:21 -0800 (PST) From: Jiong Wang To: ast@kernel.org, daniel@iogearbox.net Cc: netdev@vger.kernel.org, oss-drivers@netronome.com, Jiong Wang Subject: [PATCH bpf-next v4 02/16] bpf: refactor verifier min/max code for condition jump Date: Sat, 26 Jan 2019 12:26:00 -0500 Message-Id: <1548523574-18316-3-git-send-email-jiong.wang@netronome.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1548523574-18316-1-git-send-email-jiong.wang@netronome.com> References: <1548523574-18316-1-git-send-email-jiong.wang@netronome.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The current min/max code does both signed and unsigned comparisons against the input argument "val" which is "u64" and there is explicit type casting when the comparison is signed. As we will need slightly more complexer type casting when JMP32 introduced, it is better to host the signed type casting. This makes the code more clean with ignorable runtime overhead. Also, code for J*GE/GT/LT/LE and JEQ/JNE are very similar, this patch combine them. The main purpose for this refactor is to make sure the min/max code will still be readable and with minimum code duplication after JMP32 introduced. Reviewed-by: Jakub Kicinski Signed-off-by: Jiong Wang --- kernel/bpf/verifier.c | 172 +++++++++++++++++++++++++++++--------------------- 1 file changed, 99 insertions(+), 73 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8cfe39e..eae6cb1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4033,9 +4033,13 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, */ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) { + s64 sval; + if (__is_pointer_value(false, reg)) return -1; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: if (tnum_is_const(reg->var_off)) @@ -4058,9 +4062,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGT: - if (reg->smin_value > (s64)val) + if (reg->smin_value > sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLT: @@ -4070,9 +4074,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLT: - if (reg->smax_value < (s64)val) + if (reg->smax_value < sval) return 1; - else if (reg->smin_value >= (s64)val) + else if (reg->smin_value >= sval) return 0; break; case BPF_JGE: @@ -4082,9 +4086,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGE: - if (reg->smin_value >= (s64)val) + if (reg->smin_value >= sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLE: @@ -4094,9 +4098,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLE: - if (reg->smax_value <= (s64)val) + if (reg->smax_value <= sval) return 1; - else if (reg->smin_value > (s64)val) + else if (reg->smin_value > sval) return 0; break; } @@ -4113,6 +4117,8 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + s64 sval; + /* If the dst_reg is a pointer, we can't learn anything about its * variable offset from the compare (unless src_reg were a pointer into * the same object, but we don't bother with that. @@ -4122,19 +4128,22 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, if (__is_pointer_value(false, false_reg)) return; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + /* For BPF_JEQ, if this is false we know nothing Jon Snow, but + * if it is true we know the value for sure. Likewise for + * BPF_JNE. */ - __mark_reg_known(false_reg, val); + __mark_reg_known(reg, val); break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4142,38 +4151,46 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - false_reg->umax_value = min(false_reg->umax_value, val); - true_reg->umin_value = max(true_reg->umin_value, val + 1); - break; - case BPF_JSGT: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - break; - case BPF_JLT: - false_reg->umin_value = max(false_reg->umin_value, val); - true_reg->umax_value = min(true_reg->umax_value, val - 1); - break; - case BPF_JSLT: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - break; case BPF_JGE: - false_reg->umax_value = min(false_reg->umax_value, val - 1); - true_reg->umin_value = max(true_reg->umin_value, val); + case BPF_JGT: + { + u64 false_umax = opcode == BPF_JGT ? val : val - 1; + u64 true_umin = opcode == BPF_JGT ? val + 1 : val; + + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSGE: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); + case BPF_JSGT: + { + s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; + + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } case BPF_JLE: - false_reg->umin_value = max(false_reg->umin_value, val + 1); - true_reg->umax_value = min(true_reg->umax_value, val); + case BPF_JLT: + { + u64 false_umin = opcode == BPF_JLT ? val : val + 1; + u64 true_umax = opcode == BPF_JLT ? val - 1 : val; + + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSLE: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); + case BPF_JSLT: + { + s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; + + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } default: break; } @@ -4198,22 +4215,23 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + s64 sval; + if (__is_pointer_value(false, false_reg)) return; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; - */ - __mark_reg_known(false_reg, val); + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + __mark_reg_known(reg, val); break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4221,38 +4239,46 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - true_reg->umax_value = min(true_reg->umax_value, val - 1); - false_reg->umin_value = max(false_reg->umin_value, val); - break; - case BPF_JSGT: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - break; - case BPF_JLT: - true_reg->umin_value = max(true_reg->umin_value, val + 1); - false_reg->umax_value = min(false_reg->umax_value, val); - break; - case BPF_JSLT: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - break; case BPF_JGE: - true_reg->umax_value = min(true_reg->umax_value, val); - false_reg->umin_value = max(false_reg->umin_value, val + 1); + case BPF_JGT: + { + u64 false_umin = opcode == BPF_JGT ? val : val + 1; + u64 true_umax = opcode == BPF_JGT ? val - 1 : val; + + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSGE: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); + case BPF_JSGT: + { + s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval; + + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } case BPF_JLE: - true_reg->umin_value = max(true_reg->umin_value, val); - false_reg->umax_value = min(false_reg->umax_value, val - 1); + case BPF_JLT: + { + u64 false_umax = opcode == BPF_JLT ? val : val - 1; + u64 true_umin = opcode == BPF_JLT ? val + 1 : val; + + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSLE: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); + case BPF_JSLT: + { + s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval; + + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } default: break; }