From patchwork Fri May 13 00:13:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 9086971 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id BDCF99F1D3 for ; Fri, 13 May 2016 00:16:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0F4C320204 for ; Fri, 13 May 2016 00:16:51 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4DFD5200D0 for ; Fri, 13 May 2016 00:16:50 +0000 (UTC) Received: from localhost ([::1]:60318 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b10mf-000475-Cq for patchwork-qemu-devel@patchwork.kernel.org; Thu, 12 May 2016 20:16:49 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38380) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b10kX-0000CW-Td for qemu-devel@nongnu.org; Thu, 12 May 2016 20:14:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b10kR-0002hq-W3 for qemu-devel@nongnu.org; Thu, 12 May 2016 20:14:36 -0400 Received: from mail-qk0-x242.google.com ([2607:f8b0:400d:c09::242]:33544) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b10kR-0002hl-Rt for qemu-devel@nongnu.org; Thu, 12 May 2016 20:14:31 -0400 Received: by mail-qk0-x242.google.com with SMTP id q184so7152083qkf.0 for ; Thu, 12 May 2016 17:14:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=fNFNrnQjL8Fo7BIDls9w0VKIB4Y91144gAkzh3AqXTE=; b=wwhZKBsGOECFDQtYFBYEAcwWQE3YDjhP3pE6f3hm16m3XN3FppqnH0CpMkaRIvNgah 57ICnZElXCwH8Mp42t6NltfhPMBKVMWMMp1smxi+O/JUXAwgaw9jk3Ys1Oixh+rlENWR jwPTIF0qw9btMPDGde/s7aaNU7qrEdKCb2dazNJe29weloJ3QXYBigY4FUE8nwe/GSaq dKoCDkhOp7kWXq01V6p37sSRisAiNJY8xnKHTxJb+ks2JtIVn5fbgDteo7dPIuy4U92Y 073PU0JjxHP9S8jorkwXsEioTyeZ8d2lkFDWyxRkr8ll+JeOJ/7yDxCAPI/btE9DTsZq rlzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=fNFNrnQjL8Fo7BIDls9w0VKIB4Y91144gAkzh3AqXTE=; b=g1kyo4xMkpmZCO1XZxiHWdC7gHyj5w3O1mRzDldM0fVZ2wyh63VRd8OWy6IH2x5yw0 o/5jgttZZQK6IhGg4yYDtdsdmA+KCH381NaGb7POmpobjSBNfOBR0IszKor+9XDHuT9Y vL8uWGSbvMmp45oGC6H3xJtWAvKQ70ZJpOgi2IVNet2Qy313V0JIUeyZV81Ivn93c5ow LspOiqEuXSNVHNBm0mAf76sQ+RvoezI4vw0jHw9jS6KuCcmAvC1SjWcORPOpd0OfGv0S Ab3A7sfr1vWBBvZQfMRvaiihdjeinWTbnhnJHmlVjKRKS17RPSjVQTWr2aGCVeXCMFO2 TXdw== X-Gm-Message-State: AOPr4FWhyOpJQxsvfsgB/QKWHbresTRqjx7PXdEhVt79WSsJ4LZ9OG281rtwOB22O8Ksvw== X-Received: by 10.55.40.38 with SMTP id o38mr11601473qkh.156.1463098471520; Thu, 12 May 2016 17:14:31 -0700 (PDT) Received: from bigtime.com ([172.56.44.137]) by smtp.gmail.com with ESMTPSA id w16sm7171321qka.35.2016.05.12.17.14.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 May 2016 17:14:31 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Thu, 12 May 2016 14:13:07 -1000 Message-Id: <1463098420-29113-7-git-send-email-rth@twiddle.net> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1463098420-29113-1-git-send-email-rth@twiddle.net> References: <1463098420-29113-1-git-send-email-rth@twiddle.net> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400d:c09::242 Subject: [Qemu-devel] [PULL 06/39] tcg/i386: Make direct jump patching thread-safe X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, Sergey Fedorov , Sergey Fedorov Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sergey Fedorov Ensure direct jump patching in i386 is atomic by: * naturally aligning a location of direct jump address; * using atomic_read()/atomic_set() for code patching. tcg_out_nopn() implementation: Suggested-by: Richard Henderson . Signed-off-by: Sergey Fedorov Signed-off-by: Sergey Fedorov Message-Id: <1461341333-19646-6-git-send-email-sergey.fedorov@linaro.org> Signed-off-by: Richard Henderson --- include/exec/exec-all.h | 2 +- tcg/i386/tcg-target.inc.c | 23 +++++++++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index d49befd..0ab7803 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -313,7 +313,7 @@ void ppc_tb_set_jmp_target(uintptr_t jmp_addr, uintptr_t addr); static inline void tb_set_jmp_target1(uintptr_t jmp_addr, uintptr_t addr) { /* patch the branch destination */ - stl_le_p((void*)jmp_addr, addr - (jmp_addr + 4)); + atomic_set((int32_t *)jmp_addr, addr - (jmp_addr + 4)); /* no need to flush icache explicitly */ } #elif defined(__s390x__) diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index 007407c..8d242a6 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -1123,6 +1123,21 @@ static void tcg_out_jmp(TCGContext *s, tcg_insn_unit *dest) tcg_out_branch(s, 0, dest); } +static void tcg_out_nopn(TCGContext *s, int n) +{ + int i; + /* Emit 1 or 2 operand size prefixes for the standard one byte nop, + * "xchg %eax,%eax", forming "xchg %ax,%ax". All cores accept the + * duplicate prefix, and all of the interesting recent cores can + * decode and discard the duplicates in a single cycle. + */ + tcg_debug_assert(n >= 1); + for (i = 1; i < n; ++i) { + tcg_out8(s, 0x66); + } + tcg_out8(s, 0x90); +} + #if defined(CONFIG_SOFTMMU) /* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr, * int mmu_idx, uintptr_t ra) @@ -1777,6 +1792,14 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, case INDEX_op_goto_tb: if (s->tb_jmp_offset) { /* direct jump method */ + int gap; + /* jump displacement must be aligned for atomic patching; + * see if we need to add extra nops before jump + */ + gap = tcg_pcrel_diff(s, QEMU_ALIGN_PTR_UP(s->code_ptr + 1, 4)); + if (gap != 1) { + tcg_out_nopn(s, gap - 1); + } tcg_out8(s, OPC_JMP_long); /* jmp im */ s->tb_jmp_offset[args[0]] = tcg_current_code_size(s); tcg_out32(s, 0);