From patchwork Wed Mar 4 15:47:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11420319 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EA25D14B7 for ; Wed, 4 Mar 2020 15:48:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEC35217F4 for ; Wed, 4 Mar 2020 15:48:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jU92eUOq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387860AbgCDPsA (ORCPT ); Wed, 4 Mar 2020 10:48:00 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:34627 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729796AbgCDPr7 (ORCPT ); Wed, 4 Mar 2020 10:47:59 -0500 Received: by mail-wr1-f68.google.com with SMTP id z15so3016470wrl.1 for ; Wed, 04 Mar 2020 07:47:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WWtZI2A0hmIEG0llfgLQpxiUN3KWtDRPNvPAySOvq1M=; b=jU92eUOq+o3P7YhmDESj75RV80CCOdz8tebb+gqNx9vXBekAvvAKMv+AXjhUJOqy2Z Y8yYA2y1wbMx9jy9pFfVZbTtvjFvAWiKxYCmAUT2oMT7SeA1uQ+2SV8KlfQPr7xXFetB JLKxcbEOjtZekwFqdxae9Gux7jubloD72evcQ= 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:mime-version:content-transfer-encoding; bh=WWtZI2A0hmIEG0llfgLQpxiUN3KWtDRPNvPAySOvq1M=; b=pSy4Vo1zfpVDhwlgbRDq9V9AMJx7GUjZ6+33/Q8ZBvSOr4yWuJ5BcBB0KFLWMi/DNS 7Tp07PRQNxghz4jDYEltDy3j7ZeyqMya6Dk8ePKKdtk0/Lqq2mBU0XI1s/8lUpBT0QM8 Tpt/Kt6ln6Qsfca0ckAlVUmob1L601JtTTUWXdv2amjo95Og0pnDsmHCOAiPXqGDntAP lKBzXVbwrMKVLaS2SU/fmYABK9Pu3SMLYr7zR39mmEkluaD9N+9M4EcQWF8/qk1i+gro 2TuC9bSjck4+dXFYo1vL9pAANxyHSlGAz0BQNn+6qW9O9zajBcJl7MmeuKYEfInapk8l /yjw== X-Gm-Message-State: ANhLgQ1yXOUknqkEIoyDEdqmCYkz6I/kZvfEyyzjVIWdRp2wwM3VzHco O9UdyhMKvS9DQ1u4H0PM0019U+o/b0I= X-Google-Smtp-Source: ADFU+vuQvIeSRpB8htDrCccbaPFd8EuNPWKA0fKMxmCPXPXyRaki1owsrq6sPCRhSspI5pExfQwPbw== X-Received: by 2002:a5d:60c2:: with SMTP id x2mr4587045wrt.123.1583336877192; Wed, 04 Mar 2020 07:47:57 -0800 (PST) Received: from kpsingh-kernel.localdomain ([2a00:79e1:abc:308:8ca0:6f80:af01:b24]) by smtp.gmail.com with ESMTPSA id u25sm4816091wml.17.2020.03.04.07.47.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 07:47:56 -0800 (PST) From: KP Singh To: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Andrii Nakryiko , Alexei Starovoitov , Daniel Borkmann , Paul Turner , Jann Horn , Florent Revest , Brendan Jackman Subject: [PATCH bpf-next v3 2/7] bpf: JIT helpers for fmod_ret progs Date: Wed, 4 Mar 2020 16:47:42 +0100 Message-Id: <20200304154747.23506-3-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200304154747.23506-1-kpsingh@chromium.org> References: <20200304154747.23506-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh * Split the invoke_bpf program to prepare for special handling of fmod_ret programs introduced in a subsequent patch. * Move the definition of emit_cond_near_jump and emit_nops as they are needed for fmod_ret. * Refactor branch target alignment into its own generic helper function i.e. emit_align. Signed-off-by: KP Singh Acked-by: Andrii Nakryiko --- arch/x86/net/bpf_jit_comp.c | 148 +++++++++++++++++++++--------------- 1 file changed, 85 insertions(+), 63 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 15c7d28bc05c..d6349e930b06 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1361,35 +1361,95 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args, -(stack_size - i * 8)); } +static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, + struct bpf_prog *p, int stack_size) +{ + u8 *prog = *pprog; + int cnt = 0; + + if (emit_call(&prog, __bpf_prog_enter, prog)) + return -EINVAL; + /* remember prog start time returned by __bpf_prog_enter */ + emit_mov_reg(&prog, true, BPF_REG_6, BPF_REG_0); + + /* arg1: lea rdi, [rbp - stack_size] */ + EMIT4(0x48, 0x8D, 0x7D, -stack_size); + /* arg2: progs[i]->insnsi for interpreter */ + if (!p->jited) + emit_mov_imm64(&prog, BPF_REG_2, + (long) p->insnsi >> 32, + (u32) (long) p->insnsi); + /* call JITed bpf program or interpreter */ + if (emit_call(&prog, p->bpf_func, prog)) + return -EINVAL; + + /* arg1: mov rdi, progs[i] */ + emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, + (u32) (long) p); + /* arg2: mov rsi, rbx <- start time in nsec */ + emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6); + if (emit_call(&prog, __bpf_prog_exit, prog)) + return -EINVAL; + + *pprog = prog; + return 0; +} + +static void emit_nops(u8 **pprog, unsigned int len) +{ + unsigned int i, noplen; + u8 *prog = *pprog; + int cnt = 0; + + while (len > 0) { + noplen = len; + + if (noplen > ASM_NOP_MAX) + noplen = ASM_NOP_MAX; + + for (i = 0; i < noplen; i++) + EMIT1(ideal_nops[noplen][i]); + len -= noplen; + } + + *pprog = prog; +} + +static void emit_align(u8 **pprog, u32 align) +{ + u8 *target, *prog = *pprog; + + target = PTR_ALIGN(prog, align); + if (target != prog) + emit_nops(&prog, target - prog); + + *pprog = prog; +} + +static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond) +{ + u8 *prog = *pprog; + int cnt = 0; + s64 offset; + + offset = func - (ip + 2 + 4); + if (!is_simm32(offset)) { + pr_err("Target %p is out of range\n", func); + return -EINVAL; + } + EMIT2_off32(0x0F, jmp_cond + 0x10, offset); + *pprog = prog; + return 0; +} + static int invoke_bpf(const struct btf_func_model *m, u8 **pprog, struct bpf_tramp_progs *tp, int stack_size) { + int i; u8 *prog = *pprog; - int cnt = 0, i; for (i = 0; i < tp->nr_progs; i++) { - if (emit_call(&prog, __bpf_prog_enter, prog)) - return -EINVAL; - /* remember prog start time returned by __bpf_prog_enter */ - emit_mov_reg(&prog, true, BPF_REG_6, BPF_REG_0); - - /* arg1: lea rdi, [rbp - stack_size] */ - EMIT4(0x48, 0x8D, 0x7D, -stack_size); - /* arg2: progs[i]->insnsi for interpreter */ - if (!tp->progs[i]->jited) - emit_mov_imm64(&prog, BPF_REG_2, - (long) tp->progs[i]->insnsi >> 32, - (u32) (long) tp->progs[i]->insnsi); - /* call JITed bpf program or interpreter */ - if (emit_call(&prog, tp->progs[i]->bpf_func, prog)) - return -EINVAL; - - /* arg1: mov rdi, progs[i] */ - emit_mov_imm64(&prog, BPF_REG_1, (long) tp->progs[i] >> 32, - (u32) (long) tp->progs[i]); - /* arg2: mov rsi, rbx <- start time in nsec */ - emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6); - if (emit_call(&prog, __bpf_prog_exit, prog)) + if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size)) return -EINVAL; } *pprog = prog; @@ -1531,42 +1591,6 @@ int arch_prepare_bpf_trampoline(void *image, void *image_end, return prog - (u8 *)image; } -static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond) -{ - u8 *prog = *pprog; - int cnt = 0; - s64 offset; - - offset = func - (ip + 2 + 4); - if (!is_simm32(offset)) { - pr_err("Target %p is out of range\n", func); - return -EINVAL; - } - EMIT2_off32(0x0F, jmp_cond + 0x10, offset); - *pprog = prog; - return 0; -} - -static void emit_nops(u8 **pprog, unsigned int len) -{ - unsigned int i, noplen; - u8 *prog = *pprog; - int cnt = 0; - - while (len > 0) { - noplen = len; - - if (noplen > ASM_NOP_MAX) - noplen = ASM_NOP_MAX; - - for (i = 0; i < noplen; i++) - EMIT1(ideal_nops[noplen][i]); - len -= noplen; - } - - *pprog = prog; -} - static int emit_fallback_jump(u8 **pprog) { u8 *prog = *pprog; @@ -1589,7 +1613,7 @@ static int emit_fallback_jump(u8 **pprog) static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs) { - u8 *jg_reloc, *jg_target, *prog = *pprog; + u8 *jg_reloc, *prog = *pprog; int pivot, err, jg_bytes = 1, cnt = 0; s64 jg_offset; @@ -1644,9 +1668,7 @@ static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs) * Coding Rule 11: All branch targets should be 16-byte * aligned. */ - jg_target = PTR_ALIGN(prog, 16); - if (jg_target != prog) - emit_nops(&prog, jg_target - prog); + emit_align(&prog, 16); jg_offset = prog - jg_reloc; emit_code(jg_reloc - jg_bytes, jg_offset, jg_bytes);