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[174.21.142.130]) by smtp.gmail.com with ESMTPSA id l18-20020a056a00141200b004f75395b2cesm18258153pfu.150.2022.03.13.21.43.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Mar 2022 21:43:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LFfrJYY5Ma0BjX1lYohp7IXb94eb73+HfKk9HI5l13k=; b=YrZ3jsnLM3czeMzWYH9P3kmmZtzf6Ix9noe7QgMtyHfKkYJ/paQEyfct/TcN1VBY0O m0i8/IA+lufPHLkYlQCxIM3VA0jVEHZApmJn+E03Yq2TRtiwDEkp9+0vVp3Um8lSoeCE JAvC+U7Yeu15t6FQH/4vz8LUEQ2vIftTeTbsooKzBqDNlY/UYSYOatOpMg6Ti3aN17Vi keNzegvIbJytmav8K9zcDBpjImQtSa4SJBmGWY7pH8fLBS0iTcMc4Jy3TRVCutwgxvw/ sobkF2YCkaE/IgrQ/dDOfXAC9ewN5EkxKvtjwPOuXo8mDVzqFBpa+nIZd41kzRkr00ot EAUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LFfrJYY5Ma0BjX1lYohp7IXb94eb73+HfKk9HI5l13k=; b=AjORhAKAPHSrYRgGNAJ1sK8qwxYUGSi/qdfzFPj2meD8y+akF6l3Y4XEdgBujz7q8v GV6nu+bQDmytc/xdej0gm0y4kqqQsHrF8rEbl/3PeX8GIoXpoE9oSlMmhZwLqzziXqDV y5rjelhW1xHP7BuZahnOdOn+pOacCvzmrPDPjHGCju85zJo8fj8V38fouXEx1dvPQ1fB sgxT8re96NaIREoLsW6b4X4Em115+hfrZtrdbxVBXb9HjeeTAJSoUxhTRNQ33lz6eNs7 71C78IDUZ3cGazZGWmTebMcsRzcnDdEa+YoJiMgTTQw8iLMXH7B0xOEgIJ6gaeiHMcyP 6Nmw== X-Gm-Message-State: AOAM531UQS5nSIzvtQJJRkhN619OzYPbbgSqYm/u5RnK2STFfak3Wt8o qH10QfF7R9H5sLFuhlsP5IJNPLyOEdw18w== X-Google-Smtp-Source: ABdhPJyy4RPV/Y2zkFw2ZsNF4OUnTFm1o5Eiu7ezqnzzRAPLKonFqQKx1Dz8PsiwvzHsF+I8TdDHlA== X-Received: by 2002:a65:68d6:0:b0:380:7ef:30cf with SMTP id k22-20020a6568d6000000b0038007ef30cfmr18269455pgt.271.1647232988120; Sun, 13 Mar 2022 21:43:08 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH 1/3] linux-user/arm: Implement __kernel_memory_barrier Date: Sun, 13 Mar 2022 21:43:03 -0700 Message-Id: <20220314044305.138794-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220314044305.138794-1-richard.henderson@linaro.org> References: <20220314044305.138794-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::429 (failed) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::429; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x429.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, PDS_HP_HELO_NORDNS=0.659, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-arm@nongnu.org, laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1647233213855100001 Content-Type: text/plain; charset="utf-8" This fallback syscall was stubbed out. It would only matter for emulating pre-armv6. Signed-off-by: Richard Henderson Reviewed-by: Peter Maydell --- linux-user/arm/cpu_loop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c index 032e1ffddf..a0e43b261c 100644 --- a/linux-user/arm/cpu_loop.c +++ b/linux-user/arm/cpu_loop.c @@ -158,7 +158,7 @@ do_kernel_trap(CPUARMState *env) =20 switch (env->regs[15]) { case 0xffff0fa0: /* __kernel_memory_barrier */ - /* ??? No-op. Will need to do better for SMP. */ + smp_mb(); break; case 0xffff0fc0: /* __kernel_cmpxchg */ /* XXX: This only works between threads, not between processes. --=20 2.25.1 From nobody Mon Feb 9 19:43:17 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1647233291; cv=none; d=zohomail.com; s=zohoarc; b=d2eOB1+gE7hI3lLQBr9SBIWYiiVndMbx3At8USOU5tGCJljESsXYaV4S8B8zLo6nh6m/LAxQ/qK4I47HSsxWZRoz6RYTWpD5MBGQqlp8x2PenQgUK/cxidS7GxJz2Cz5CNBvup2E/cogPPU1SsKsknc++2CD1VdycGiLVqDczEQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1647233291; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=lXfB6B+XqNR5xcS/TG/PElhQ8wbvELzxHwZ/ZITikII=; b=Ug+rW4mvcosrvHDVRu+REziikYcOeaB/ry2a+eqrxYnTujuvBztCazJHnXG2yBZOVHvBwEVWCRMEnXdL8cuAQQE9g6aNz+re90mLkEq1qQCtirlO2Orcnat7J5D30FzGtgj0CO3dAYmV17fHUscxzuBfwvxI2DNAIyhpUzwT0lU= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1647233291053126.55475428692966; Sun, 13 Mar 2022 21:48:11 -0700 (PDT) Received: from localhost ([::1]:51332 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nTccr-0001wL-00 for importer@patchew.org; Mon, 14 Mar 2022 00:48:10 -0400 Received: from eggs.gnu.org ([209.51.188.92]:50062) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nTcY4-0003DD-6f for qemu-devel@nongnu.org; Mon, 14 Mar 2022 00:43:13 -0400 Received: from [2607:f8b0:4864:20::434] (port=37483 helo=mail-pf1-x434.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nTcY2-0004Oo-Je for qemu-devel@nongnu.org; Mon, 14 Mar 2022 00:43:11 -0400 Received: by mail-pf1-x434.google.com with SMTP id t5so13230149pfg.4 for ; Sun, 13 Mar 2022 21:43:09 -0700 (PDT) Received: from localhost.localdomain (174-21-142-130.tukw.qwest.net. [174.21.142.130]) by smtp.gmail.com with ESMTPSA id l18-20020a056a00141200b004f75395b2cesm18258153pfu.150.2022.03.13.21.43.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Mar 2022 21:43:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lXfB6B+XqNR5xcS/TG/PElhQ8wbvELzxHwZ/ZITikII=; b=VweupA+xP8WZZ+y5fvL1xPzWUC67e1jgCvXMDCoPxnp1WSvTk/hwLDTOTyCvTVWspE uVbj+CO1pjH5QxxpTHm2dZcUhKflHeu77kVBW68OBrpC4tNde5a8xjdyPRPOnQellKpQ OJnMhkw64CPe808MN6ehDYWxVF7naV4zhbiadCEjjgjEKHma3QWOdGK9C9bqaQi76ne2 qCGfNXP9aGtOgFjAoStPBKdZe1THCrIgtotk57Ok3wlvIdd7ys8flqfY6jf6oF536c7Z i1C1N5p/K2SU175mM5RI6/Jn6fptxX8Wjbr3eyZqOVr8O0y3DJQ784k6/FPLizTDKLeG nwtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=lXfB6B+XqNR5xcS/TG/PElhQ8wbvELzxHwZ/ZITikII=; b=wvqARGwOuOPT6sWY4u62nXbO5NAJpTQoRL5MeZgn0W9Ti+qdibpTEo6tbMjz2A193G 9xkyLDQ4y/yNRIPuQB/XxBUlH6zoy3x5CCzep42rfs8yTJoC4nMrwW9gM8lilpAnpZ3w OvwZ3MrOvTz59DnWpFyzIzO0n+uR71Syui6f8a12pSTT/Z65MbDiiZPr6mE5iJeY2fg2 5xce1P4QAbUWk6lRnYPGhg2hq9j1lrB6GfskW3u0nq1nQicQNeTDZneS+aE8R1kaImtM AShiviVtjf87+QpCEJKo8JC+ciQgjhGg/TFRKsEcki+AFywZxVXyPirsbrrf+OfPhZfz +9SA== X-Gm-Message-State: AOAM531RxmkAb6fWTgcT5PpD1ucCV9naaN9CzCH/7stGdAvrWrwNHBg6 5tr7TrYouJHy/VoouMgWbSHWHUL5X0HEfA== X-Google-Smtp-Source: ABdhPJyumgCTgSWjLQbvtZzPIGtW/M/vxdlqYjNcSL5ZlnvfpWn9QPS5uYzwX4Iy/ix+++i1hPc9qg== X-Received: by 2002:a63:2a0e:0:b0:380:aeb3:d46c with SMTP id q14-20020a632a0e000000b00380aeb3d46cmr18441023pgq.404.1647232988795; Sun, 13 Mar 2022 21:43:08 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH 2/3] linux-user/arm: Implement __kernel_cmpxchg with host atomics Date: Sun, 13 Mar 2022 21:43:04 -0700 Message-Id: <20220314044305.138794-3-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220314044305.138794-1-richard.henderson@linaro.org> References: <20220314044305.138794-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::434 (failed) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::434; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x434.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, PDS_HP_HELO_NORDNS=0.659, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-arm@nongnu.org, laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1647233292317100001 Content-Type: text/plain; charset="utf-8" The existing implementation using start/end_exclusive does not provide atomicity across processes. Signed-off-by: Richard Henderson Reviewed-by: Peter Maydell --- linux-user/arm/cpu_loop.c | 85 +++++++++++++++++++++++++++------------ 1 file changed, 60 insertions(+), 25 deletions(-) diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c index a0e43b261c..0122bb34f7 100644 --- a/linux-user/arm/cpu_loop.c +++ b/linux-user/arm/cpu_loop.c @@ -75,7 +75,65 @@ put_user_u16(__x, (gaddr)); \ }) =20 -/* Commpage handling -- there is no commpage for AArch64 */ +/* + * Similar to code in accel/tcg/user-exec.c, but outside the execution loo= p. + * Must be called with mmap_lock. + */ +static void *atomic_mmu_lookup(CPUArchState *env, uint32_t addr, int size) +{ + int need_flags =3D PAGE_READ | PAGE_WRITE_ORG | PAGE_VALID; + int page_flags; + + /* Enforce guest required alignment. */ + if (unlikely(addr & (size - 1))) { + force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); + return NULL; + } + + page_flags =3D page_get_flags(addr); + if (unlikely((page_flags & need_flags) !=3D need_flags)) { + force_sig_fault(TARGET_SIGSEGV, + page_flags & PAGE_VALID ? + TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr); + return NULL; + } + + return g2h(env_cpu(env), addr); +} + +/* + * See the Linux kernel's Documentation/arm/kernel_user_helpers.rst + * Input: + * r0 =3D oldval + * r1 =3D newval + * r2 =3D pointer to target value + * + * Output: + * r0 =3D 0 if *ptr was changed, non-0 if no exchange happened + * C set if *ptr was changed, clear if no exchange happened + */ +static void arm_kernel_cmpxchg32_helper(CPUARMState *env) +{ + uint32_t oldval, newval, val, addr, cpsr, *host_addr; + + oldval =3D env->regs[0]; + newval =3D env->regs[1]; + addr =3D env->regs[2]; + + mmap_lock(); + host_addr =3D atomic_mmu_lookup(env, addr, 8); + if (!host_addr) { + mmap_unlock(); + return; + } + + val =3D qatomic_cmpxchg__nocheck(host_addr, oldval, newval); + mmap_unlock(); + + cpsr =3D (val =3D=3D oldval) * CPSR_C; + cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); + env->regs[0] =3D cpsr ? 0 : -1; +} =20 /* * See the Linux kernel's Documentation/arm/kernel_user_helpers.txt @@ -153,36 +211,13 @@ static int do_kernel_trap(CPUARMState *env) { uint32_t addr; - uint32_t cpsr; - uint32_t val; =20 switch (env->regs[15]) { case 0xffff0fa0: /* __kernel_memory_barrier */ smp_mb(); break; case 0xffff0fc0: /* __kernel_cmpxchg */ - /* XXX: This only works between threads, not between processes. - It's probably possible to implement this with native host - operations. However things like ldrex/strex are much harder so - there's not much point trying. */ - start_exclusive(); - cpsr =3D cpsr_read(env); - addr =3D env->regs[2]; - /* FIXME: This should SEGV if the access fails. */ - if (get_user_u32(val, addr)) - val =3D ~env->regs[0]; - if (val =3D=3D env->regs[0]) { - val =3D env->regs[1]; - /* FIXME: Check for segfaults. */ - put_user_u32(val, addr); - env->regs[0] =3D 0; - cpsr |=3D CPSR_C; - } else { - env->regs[0] =3D -1; - cpsr &=3D ~CPSR_C; - } - cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); - end_exclusive(); + arm_kernel_cmpxchg32_helper(env); break; case 0xffff0fe0: /* __kernel_get_tls */ env->regs[0] =3D cpu_get_tls(env); --=20 2.25.1 From nobody Mon Feb 9 19:43:17 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1647233113; cv=none; d=zohomail.com; s=zohoarc; b=fAVOEDdgWj1S0HsNaT99XEvKtZLC1sGyQRMaiHm0QV/5kJMbzFDKKZzSUCrRaWVDAiAdptRuL2ka+8S4x5LDz8XemH9Cq2SJSGlTgmq5YqWKKFp+IbHBRZJEPQzlGaLN6qoOUDezeqXCUpqJtsAKWG9jCF3EP8v7Yyedcf+Lzf0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1647233113; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=cXCVIH7QbmZmA9NvwqwE9kMzF0Kq89R2K/T6009maKI=; b=nhb598D4ePqYPjb1oIx8oT2fAPyn0jVql3H5wuCT23klRiU0PiWh4XmEsYT9Mv1RJtvVaWJIHyDJp8TpkQfvWlWjGA3pdFQ3+cLpkz8bZTrfL9B+XUBobR+0TTYTXsHmsbMR1E/RYpE2RDeCqcaZvzkRBpW4/MMW7SoOslz5d+o= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1647233113692865.8166582876869; Sun, 13 Mar 2022 21:45:13 -0700 (PDT) Received: from localhost ([::1]:43760 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nTca0-0005D2-A1 for importer@patchew.org; Mon, 14 Mar 2022 00:45:12 -0400 Received: from eggs.gnu.org ([209.51.188.92]:50064) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nTcY4-0003DE-Hl for qemu-devel@nongnu.org; Mon, 14 Mar 2022 00:43:13 -0400 Received: from [2607:f8b0:4864:20::62d] (port=38872 helo=mail-pl1-x62d.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nTcY2-0004PB-PS for qemu-devel@nongnu.org; Mon, 14 Mar 2022 00:43:12 -0400 Received: by mail-pl1-x62d.google.com with SMTP id n18so9842401plg.5 for ; Sun, 13 Mar 2022 21:43:10 -0700 (PDT) Received: from localhost.localdomain (174-21-142-130.tukw.qwest.net. [174.21.142.130]) by smtp.gmail.com with ESMTPSA id l18-20020a056a00141200b004f75395b2cesm18258153pfu.150.2022.03.13.21.43.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Mar 2022 21:43:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=cXCVIH7QbmZmA9NvwqwE9kMzF0Kq89R2K/T6009maKI=; b=dz6nzMwVUdsXRCSMZRwfKSBpmM+u9enzfEceZtKo4p2QXg3hc2AJ08K8gLzBlM/n2T eve6+J5NO0QBj9RMK2hqkYGGe1NBfIMU+mSMK61AhFoDbfj2JeP80mu5YLzVtey1P+bz fat8sT+RQKLby+uCO+E3buy61U4bpBe3III85KVIcbqQesv8kqwV84ruQzPsGkROUS3u 1RQ4L04KUj8p7BrBOzt3kA7nAETTLxzmxmfTY4IHJODM4QZLHirq5s8pyZ7EZTbY/5hZ EoXchcz7zplHkk8+6xHbdn9wyjCmPV9sRGixOde1b1HxKl+jCENCivgLjEg18KqD7Dv3 mCxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=cXCVIH7QbmZmA9NvwqwE9kMzF0Kq89R2K/T6009maKI=; b=zU7uzWsNKLXCEZDfWcR+gbQCdinLBEkgDJOkAa25IeESiY1UtgILPj6VS7QnBCwsnk JCSg7HTpMK2eneTmYOviT8XfYmqRlYjgxRwSj3BEfN+V3vQ13LHkZbwcwUNqTEj0/QnH WaTtDnEBDnaVGHHZdBJUXQAM4eN8Sik+8ZdufopWg4TGRG5rWyFittXtwOvXNxt0eFBH Vr2EuP8RlTlgL5yZJXswOxSTSyvvwdKIb6rEFuJhC+xlr3C/LQt6EdszBSSjA8I2ppwN D/AkBBxm7LZRHP2Zdt3qhUJYmXNUXU6WgQQVQ6W6zQMQy70I0lj9A+U/D2oa/XBW1Ttz Q+Eg== X-Gm-Message-State: AOAM530lnnkftX2tlC2TlS5MB44+0FpjQIWrl551QXPxY+RaqizJmaFG yuhCiuU8eXWI8ySVSZbI7sukNdbWgxoZ9w== X-Google-Smtp-Source: ABdhPJwfgfmS8ezj51x4Nfaxh485i2kv4htzSXa6za7GUtcEgb9QEqUX/ky+7wVCMDqKFzli/85ZQQ== X-Received: by 2002:a17:90b:4f4e:b0:1bf:88f6:e5b5 with SMTP id pj14-20020a17090b4f4e00b001bf88f6e5b5mr33607904pjb.47.1647232989556; Sun, 13 Mar 2022 21:43:09 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH 3/3] linux-user/arm: Implement __kernel_cmpxchg64 with host atomics Date: Sun, 13 Mar 2022 21:43:05 -0700 Message-Id: <20220314044305.138794-4-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220314044305.138794-1-richard.henderson@linaro.org> References: <20220314044305.138794-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::62d (failed) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::62d; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62d.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, PDS_HP_HELO_NORDNS=0.659, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-arm@nongnu.org, laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1647233115529100002 Content-Type: text/plain; charset="utf-8" If CONFIG_ATOMIC64, we can use a host cmpxchg and provide atomicity across processes; otherwise we have no choice but to continue using start/end_exclusive. Signed-off-by: Richard Henderson Reviewed-by: Peter Maydell --- linux-user/arm/cpu_loop.c | 79 +++++++++++++++++++-------------------- 1 file changed, 38 insertions(+), 41 deletions(-) diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c index 0122bb34f7..d9651f199f 100644 --- a/linux-user/arm/cpu_loop.c +++ b/linux-user/arm/cpu_loop.c @@ -136,7 +136,7 @@ static void arm_kernel_cmpxchg32_helper(CPUARMState *en= v) } =20 /* - * See the Linux kernel's Documentation/arm/kernel_user_helpers.txt + * See the Linux kernel's Documentation/arm/kernel_user_helpers.rst * Input: * r0 =3D pointer to oldval * r1 =3D pointer to newval @@ -153,57 +153,54 @@ static void arm_kernel_cmpxchg64_helper(CPUARMState *= env) { uint64_t oldval, newval, val; uint32_t addr, cpsr; + uint64_t *host_addr; =20 - /* Based on the 32 bit code in do_kernel_trap */ + addr =3D env->regs[0]; + if (get_user_u64(oldval, addr)) { + goto segv; + } =20 - /* XXX: This only works between threads, not between processes. - It's probably possible to implement this with native host - operations. However things like ldrex/strex are much harder so - there's not much point trying. */ - start_exclusive(); - cpsr =3D cpsr_read(env); + addr =3D env->regs[1]; + if (get_user_u64(newval, addr)) { + goto segv; + } + + mmap_lock(); addr =3D env->regs[2]; - - if (get_user_u64(oldval, env->regs[0])) { - env->exception.vaddress =3D env->regs[0]; - goto segv; - }; - - if (get_user_u64(newval, env->regs[1])) { - env->exception.vaddress =3D env->regs[1]; - goto segv; - }; - - if (get_user_u64(val, addr)) { - env->exception.vaddress =3D addr; - goto segv; + host_addr =3D atomic_mmu_lookup(env, addr, 8); + if (!host_addr) { + mmap_unlock(); + return; } =20 +#ifdef CONFIG_ATOMIC64 + val =3D qatomic_cmpxchg__nocheck(host_addr, oldval, newval); + cpsr =3D (val =3D=3D oldval) * CPSR_C; +#else + /* + * This only works between threads, not between processes, but since + * the host has no 64-bit cmpxchg, it is the best that we can do. + */ + start_exclusive(); + val =3D *host_addr; if (val =3D=3D oldval) { - val =3D newval; - - if (put_user_u64(val, addr)) { - env->exception.vaddress =3D addr; - goto segv; - }; - - env->regs[0] =3D 0; - cpsr |=3D CPSR_C; + *host_addr =3D newval; + cpsr =3D CPSR_C; } else { - env->regs[0] =3D -1; - cpsr &=3D ~CPSR_C; + cpsr =3D 0; } - cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); end_exclusive(); +#endif + mmap_unlock(); + + cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); + env->regs[0] =3D cpsr ? 0 : -1; return; =20 -segv: - end_exclusive(); - /* We get the PC of the entry address - which is as good as anything, - on a real kernel what you get depends on which mode it uses. */ - /* XXX: check env->error_code */ - force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MAPERR, - env->exception.vaddress); + segv: + force_sig_fault(TARGET_SIGSEGV, + page_get_flags(addr) & PAGE_VALID ? + TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr); } =20 /* Handle a jump to the kernel code page. */ --=20 2.25.1