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[174.21.142.130]) by smtp.gmail.com with ESMTPSA id g70-20020a636b49000000b003823dd39d41sm11569167pgc.64.2022.03.22.17.58.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Mar 2022 17:58:42 -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=f+5z+wqi2rxnK6aMMyUHgsuTb072LmLznpqr7TVA2Ek=; b=rY01lwXIo8Zhx5tAVaR3PTWgGZvCxW1bfFi6rbDvFCsm6ML7tmAelPntDZuOXIvzco cagmpgmaG4oS9V9eGNLbMIqGZpo/6iz2O4WKkUZoHQRtTWr/qqG89lA79YvUzLLlzw2S YGb6kShyr0XINoi/ycWYnQiKPny9Z0kgbOJ1UuGPCHp7Qw8t/xuSvV+I6JPwxv6E+iPF ZxOQUEPjgE/Jv/60stgu8bzEw59ShVKA96Lrz/ML3vJmz8HrJx1pP5mFqWUpDRWQG3uk aXVQhKIrX5kImo9dbZDTJxd89gQqBcqdfYNDlWYG82uI7GqWNZUPbwud0uO11AIrVhBi h7Vw== 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=f+5z+wqi2rxnK6aMMyUHgsuTb072LmLznpqr7TVA2Ek=; b=YtPoNCfs/g1UJVGOYkDN2Uhug2BD57wgbHlbhVYE9t7lqCU+OsgNpOpRbPoK8qubXE 51QbhqBFovAL3HUXJf85vNYnwIg0RDNAJkk+wGvvvK/4EgMqCBeItcpXF0BW2DrilkG4 UuHMzMPpnvfxDOqn/qBPDWBBLny5wzuAPYmgngOXcYNtQLbrBB531Smi9eF7voUK8VHs QIppc0pkYUoIU0A4vvHAsOYsZv/V0j4NtRmFiGW4qmSLeM2bcmvby36SfruWsauQEz6i DHTxsAEe7som37DY9aRYxSRifZrMSWhsNWsrwfO8H37oGYoGMOVhHPhHB5iUx6m7R6op R7dg== X-Gm-Message-State: AOAM530w+SHmTYLVh5mSFxnsBidNIRBgr4D5NwAh0Vy7wl/i+aC37hay UHbu1VEN0oKOjzkSHrl5JWmhyAvAQgsGdg== X-Google-Smtp-Source: ABdhPJwk9/Iw1J/0jtA27hRIZdbIabnftOisNgfD1oh2+9GwEGFlVfOxjnl2UgU9Hryi/gx3j/1CBQ== X-Received: by 2002:a17:902:f54c:b0:154:8227:a387 with SMTP id h12-20020a170902f54c00b001548227a387mr6542544plf.42.1647997123188; Tue, 22 Mar 2022 17:58:43 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v2 1/3] linux-user/arm: Implement __kernel_memory_barrier Date: Tue, 22 Mar 2022 17:58:37 -0700 Message-Id: <20220323005839.94327-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220323005839.94327-1-richard.henderson@linaro.org> References: <20220323005839.94327-1-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::62a (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::62a; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62a.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: Peter Maydell , laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1647997265880100003 Content-Type: text/plain; charset="utf-8" This fallback syscall was stubbed out. It would only matter for emulating pre-armv6. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- 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 21:25:46 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1647997264477228.67711269831284; Tue, 22 Mar 2022 18:01:04 -0700 (PDT) Received: from localhost ([::1]:43520 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nWpN1-0001Rx-CB for importer@patchew.org; Tue, 22 Mar 2022 21:01:03 -0400 Received: from eggs.gnu.org ([209.51.188.92]:56072) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWpKp-0007qY-Je for qemu-devel@nongnu.org; Tue, 22 Mar 2022 20:58:47 -0400 Received: from [2607:f8b0:4864:20::102c] (port=51172 helo=mail-pj1-x102c.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nWpKn-0001UU-Vb for qemu-devel@nongnu.org; Tue, 22 Mar 2022 20:58:47 -0400 Received: by mail-pj1-x102c.google.com with SMTP id m22so251805pja.0 for ; Tue, 22 Mar 2022 17:58:45 -0700 (PDT) Received: from localhost.localdomain (174-21-142-130.tukw.qwest.net. [174.21.142.130]) by smtp.gmail.com with ESMTPSA id g70-20020a636b49000000b003823dd39d41sm11569167pgc.64.2022.03.22.17.58.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Mar 2022 17:58:43 -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=g4ZAYkN4+Df9Z1kwRtWsg4ayeKzhHtF/+N49oTFuqzw=; b=vEsMXAdH7OX0Abv/pUT1w5q2HbmO2o905fuuVq4ndMj05R+xwYrXUSPPXQizWvSP5R 3DHyPO+NZsC2688/DqkKd4DAIqTiv5kHmHmSIkd2iMTNqnxRPRYLxVviL9wOJ4Chg/VZ Omsrvofl1IIaACbsgsMcNRdQYHwgmuwk+FzXxxZqL01cYNKgqR9UzN/mjXKuQYKi0zWV adiFOOTEl+tX8SnLPCU22fjVFeDQ1l+Cqwwieo4vTR4oUp73nfvyhWhf4YZoaZNkonp4 E1XiNW9rHpeFwylU2c6G4llD5U8GVemt/mPM74cNY4xBCBVa3sYCX8PJ7dTEwA6hTPcg TjIQ== 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=g4ZAYkN4+Df9Z1kwRtWsg4ayeKzhHtF/+N49oTFuqzw=; b=6ZRbA2I1t5C6Zveekxa9kCemaM+T/AF9NO8ziTh+l5MDwNwDS/QfBl4RHBt4+ryfcg 3Gta/ZapF8j/royWYi2+qyMmaz01uWijI69Fk6qDBT0WQEOwRjsYjFZkhY4Dl2TrXLJ0 kQT1junBA5vpvjhu+IFIeoVLguaH35lWjMTWIPGsKd9humDnPHUI1UsUDYhp8oIBNt/R +6HVAfhHkF7EqC/hH+++5R1eg7z7AoJBcpndn8n7b79Ww6rQjmu766zUUijo12I0HDYc WflpQVW9C5R4xCpOD04oATdM3JqIyHkto9aRToMxzFizP73bnlT4X2J0iOpmxkwBq6T8 vWFw== X-Gm-Message-State: AOAM530TvKQbZy0iiPdrKD4VMdE9i9xFiVU9g/fEsOrDMMHBkBwqfl2G feZkGLOxlPusnENeIPAh+CI6i1usKlRzsg== X-Google-Smtp-Source: ABdhPJydSBRYWpWr3V6SHArNhUScPj/cfs6xXPk6To7xToLwoSgpE9vUX7A+QCN/vQpTCJFt8/5yfg== X-Received: by 2002:a17:903:3051:b0:154:6fa8:2fa3 with SMTP id u17-20020a170903305100b001546fa82fa3mr9850229pla.129.1647997124477; Tue, 22 Mar 2022 17:58:44 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v2 2/3] linux-user/arm: Implement __kernel_cmpxchg with host atomics Date: Tue, 22 Mar 2022 17:58:38 -0700 Message-Id: <20220323005839.94327-3-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220323005839.94327-1-richard.henderson@linaro.org> References: <20220323005839.94327-1-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::102c (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::102c; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x102c.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: Peter Maydell , laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1647997265931100004 Content-Type: text/plain; charset="utf-8" The existing implementation using start/end_exclusive does not provide atomicity across processes. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- linux-user/arm/cpu_loop.c | 87 ++++++++++++++++++++++++++++----------- 1 file changed, 62 insertions(+), 25 deletions(-) diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c index a0e43b261c..aa2d777bf4 100644 --- a/linux-user/arm/cpu_loop.c +++ b/linux-user/arm/cpu_loop.c @@ -75,7 +75,67 @@ 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. + * 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. + */ +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, 4); + 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 +213,13 @@ 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 21:25:46 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1647997475027367.5351134130508; Tue, 22 Mar 2022 18:04:35 -0700 (PDT) Received: from localhost ([::1]:49552 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nWpQQ-0005dT-1z for importer@patchew.org; Tue, 22 Mar 2022 21:04:34 -0400 Received: from eggs.gnu.org ([209.51.188.92]:56082) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWpKr-0007s0-1Z for qemu-devel@nongnu.org; Tue, 22 Mar 2022 20:58:49 -0400 Received: from [2607:f8b0:4864:20::529] (port=44749 helo=mail-pg1-x529.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nWpKp-0001Un-Dm for qemu-devel@nongnu.org; Tue, 22 Mar 2022 20:58:48 -0400 Received: by mail-pg1-x529.google.com with SMTP id c11so13815770pgu.11 for ; Tue, 22 Mar 2022 17:58:47 -0700 (PDT) Received: from localhost.localdomain (174-21-142-130.tukw.qwest.net. [174.21.142.130]) by smtp.gmail.com with ESMTPSA id g70-20020a636b49000000b003823dd39d41sm11569167pgc.64.2022.03.22.17.58.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Mar 2022 17:58:45 -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=EAopWqbVIHUB/SJc8DJm/9zhocJ0OwWkN+8ZoF29nMQ=; b=S5WsksFhqDUPx9yznbOTPTUdj7o8RlAGIgVaR0ZVHUPDJDrnGC3e6kJjwBTt4PYmvt AAqeK8cL4n+97CeucCslTMHmgoqWU3whTY77emq+1EOBe9N6NEhQX70Tc/FP7YlmJvFP w7dEHIHXaP6xpqD05ac6k+yZbNzTmnoiiCP42+O8T3wpBfKhXcLtHZ3VKWGj3+oFPWmS oEdFDNn+5FGPhUOFHqwzlUO+PzK7cR35sCflsnNnINFo4Wqn8iITjFv8PI8YFfL9HLcO cFoqft5UwNy4fy18uIoteNPchXvMKSz7jlsZ8c9QirG34S4+0GMXN3xW0gb3t1vurrg1 znsQ== 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=EAopWqbVIHUB/SJc8DJm/9zhocJ0OwWkN+8ZoF29nMQ=; b=0/WDtdz0iHVJDUl8S/9nFrF5vPR5OB7fhLfAruf1xRmy194muAp8EzOMMd3keypPwY dcPlh4g8/GI6rE5vgxPucuqt2hRsUQ4WwI9ldO5EGpft95skXA1pGD89nsbJdkbaorHw YQlrAtnjQkBjK/AP4ul4RWQtDBKMtXiL/HVcchc0SB3TG5QFdHuhChsCtmSVylo/s02G YbMU1q46wIlw4tP3XIOMPHLOJDYsTcjbi0Vzf65k2xI8pC7xP4NpE+1lZcNvu8MlIZCk J039eI7Iw0vw+vlBq0XUxHB58JjwL/vTACHssw82LSxL8Pz2+NciM6rJw4nfWnoIVnNb nQcw== X-Gm-Message-State: AOAM533e62FHfOOYe9CLY1ZtLGIbMg6vYO4xDNtb23bOH16enjrK18t/ HLn+BKTKCtgtSr6ZMwRuUo+al5ZM8jd/vQ== X-Google-Smtp-Source: ABdhPJwVl22MbPbjvmbgtSnzYPzr4B9JniU03M4RylK5dsKcg7m7qbljgyvbhktg5Xpl/U1XPzzX6w== X-Received: by 2002:a63:1459:0:b0:381:7672:e79f with SMTP id 25-20020a631459000000b003817672e79fmr24116671pgu.214.1647997125799; Tue, 22 Mar 2022 17:58:45 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v2 3/3] linux-user/arm: Implement __kernel_cmpxchg64 with host atomics Date: Tue, 22 Mar 2022 17:58:39 -0700 Message-Id: <20220323005839.94327-4-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220323005839.94327-1-richard.henderson@linaro.org> References: <20220323005839.94327-1-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::529 (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::529; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x529.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: Peter Maydell , laurent@vivier.eu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1647997477381100001 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. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- 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 aa2d777bf4..aae375d617 100644 --- a/linux-user/arm/cpu_loop.c +++ b/linux-user/arm/cpu_loop.c @@ -138,7 +138,7 @@ 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 @@ -155,57 +155,54 @@ 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