From patchwork Thu Jan 21 14:56:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 8081971 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 599499F1CC for ; Thu, 21 Jan 2016 14:58:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A19E2204F6 for ; Thu, 21 Jan 2016 14:58:40 +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 D7CB5204E3 for ; Thu, 21 Jan 2016 14:58:39 +0000 (UTC) Received: from localhost ([::1]:48043 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMGh5-0005oH-9d for patchwork-qemu-devel@patchwork.kernel.org; Thu, 21 Jan 2016 09:58:39 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45401) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMGfA-0002QM-TT for qemu-devel@nongnu.org; Thu, 21 Jan 2016 09:56:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aMGf9-0002ir-NC for qemu-devel@nongnu.org; Thu, 21 Jan 2016 09:56:40 -0500 Received: from mnementh.archaic.org.uk ([2001:8b0:1d0::1]:59496) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMGf9-0002g6-Fu for qemu-devel@nongnu.org; Thu, 21 Jan 2016 09:56:39 -0500 Received: from pm215 by mnementh.archaic.org.uk with local (Exim 4.80) (envelope-from ) id 1aMGf0-0003Rl-9G for qemu-devel@nongnu.org; Thu, 21 Jan 2016 14:56:30 +0000 From: Peter Maydell To: qemu-devel@nongnu.org Date: Thu, 21 Jan 2016 14:56:26 +0000 Message-Id: <1453388189-13092-34-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1453388189-13092-1-git-send-email-peter.maydell@linaro.org> References: <1453388189-13092-1-git-send-email-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 2001:8b0:1d0::1 Subject: [Qemu-devel] [PULL 33/36] target-arm: Handle exception return from AArch64 to non-EL0 AArch32 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable 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 Remove the assumptions that the AArch64 exception return code was making about a return to AArch32 always being a return to EL0. This includes pulling out the illegal-SPSR checks so we can apply them for return to 32 bit as well as return to 64-bit. Signed-off-by: Peter Maydell Reviewed-by: Edgar E. Iglesias --- target-arm/op_helper.c | 80 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 59 insertions(+), 21 deletions(-) diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c index 7b6b3fd..b9f51e0 100644 --- a/target-arm/op_helper.c +++ b/target-arm/op_helper.c @@ -641,12 +641,51 @@ void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome) } } +static int el_from_spsr(uint32_t spsr) +{ + /* Return the exception level that this SPSR is requesting a return to, + * or -1 if it is invalid (an illegal return) + */ + if (spsr & PSTATE_nRW) { + switch (spsr & CPSR_M) { + case ARM_CPU_MODE_USR: + return 0; + case ARM_CPU_MODE_HYP: + return 2; + case ARM_CPU_MODE_FIQ: + case ARM_CPU_MODE_IRQ: + case ARM_CPU_MODE_SVC: + case ARM_CPU_MODE_ABT: + case ARM_CPU_MODE_UND: + case ARM_CPU_MODE_SYS: + return 1; + case ARM_CPU_MODE_MON: + /* Returning to Mon from AArch64 is never possible, + * so this is an illegal return. + */ + default: + return -1; + } + } else { + if (extract32(spsr, 1, 1)) { + /* Return with reserved M[1] bit set */ + return -1; + } + if (extract32(spsr, 0, 4) == 1) { + /* return to EL0 with M[0] bit set */ + return -1; + } + return extract32(spsr, 2, 2); + } +} + void HELPER(exception_return)(CPUARMState *env) { int cur_el = arm_current_el(env); unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el); uint32_t spsr = env->banked_spsr[spsr_idx]; int new_el; + bool return_to_aa64 = (spsr & PSTATE_nRW) == 0; aarch64_save_sp(env, cur_el); @@ -663,35 +702,34 @@ void HELPER(exception_return)(CPUARMState *env) spsr &= ~PSTATE_SS; } - if (spsr & PSTATE_nRW) { - /* TODO: We currently assume EL1/2/3 are running in AArch64. */ + new_el = el_from_spsr(spsr); + if (new_el == -1) { + goto illegal_return; + } + if (new_el > cur_el + || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) { + /* Disallow return to an EL which is unimplemented or higher + * than the current one. + */ + goto illegal_return; + } + + if (new_el != 0 && arm_el_is_aa64(env, new_el) != return_to_aa64) { + /* Return to an EL which is configured for a different register width */ + goto illegal_return; + } + + if (!return_to_aa64) { env->aarch64 = 0; - new_el = 0; - env->uncached_cpsr = 0x10; + env->uncached_cpsr = spsr & CPSR_M; cpsr_write(env, spsr, ~0); if (!arm_singlestep_active(env)) { env->uncached_cpsr &= ~PSTATE_SS; } aarch64_sync_64_to_32(env); - env->regs[15] = env->elr_el[1] & ~0x1; + env->regs[15] = env->elr_el[cur_el] & ~0x1; } else { - new_el = extract32(spsr, 2, 2); - if (new_el > cur_el - || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) { - /* Disallow return to an EL which is unimplemented or higher - * than the current one. - */ - goto illegal_return; - } - if (extract32(spsr, 1, 1)) { - /* Return with reserved M[1] bit set */ - goto illegal_return; - } - if (new_el == 0 && (spsr & PSTATE_SP)) { - /* Return to EL0 with M[0] bit set */ - goto illegal_return; - } env->aarch64 = 1; pstate_write(env, spsr); if (!arm_singlestep_active(env)) {