From nobody Thu Dec 18 13:31:49 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1492707494836299.4643705938888; Thu, 20 Apr 2017 09:58:14 -0700 (PDT) Received: from localhost ([::1]:55141 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d1FPJ-0005cs-I7 for importer@patchew.org; Thu, 20 Apr 2017 12:58:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43844) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d1F95-0008SQ-7K for qemu-devel@nongnu.org; Thu, 20 Apr 2017 12:41:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d1F92-00089G-Br for qemu-devel@nongnu.org; Thu, 20 Apr 2017 12:41:27 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:36885) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d1F92-0007wI-0G for qemu-devel@nongnu.org; Thu, 20 Apr 2017 12:41:24 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1d1F90-000711-Vj for qemu-devel@nongnu.org; Thu, 20 Apr 2017 17:41:22 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Thu, 20 Apr 2017 17:41:10 +0100 Message-Id: <1492706470-10921-25-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1492706470-10921-1-git-send-email-peter.maydell@linaro.org> References: <1492706470-10921-1-git-send-email-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PULL 24/24] arm: Remove workarounds for old M-profile exception return implementation 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Now that we've rewritten M-profile exception return so that the magic PC values are not visible to other parts of QEMU, we can delete the special casing of them elsewhere. Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Richard Henderson Message-id: 1491844419-12485-10-git-send-email-peter.maydell@linaro.org --- target/arm/cpu.c | 43 ++----------------------------------------- target/arm/translate.c | 8 -------- 2 files changed, 2 insertions(+), 49 deletions(-) diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 04b062c..b357aee 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -304,33 +304,6 @@ bool arm_cpu_exec_interrupt(CPUState *cs, int interrup= t_request) } =20 #if !defined(CONFIG_USER_ONLY) || !defined(TARGET_AARCH64) -static void arm_v7m_unassigned_access(CPUState *cpu, hwaddr addr, - bool is_write, bool is_exec, int opa= que, - unsigned size) -{ - ARMCPU *arm =3D ARM_CPU(cpu); - CPUARMState *env =3D &arm->env; - - /* ARMv7-M interrupt return works by loading a magic value into the PC. - * On real hardware the load causes the return to occur. The qemu - * implementation performs the jump normally, then does the exception - * return by throwing a special exception when when the CPU tries to - * execute code at the magic address. - */ - if (env->v7m.exception !=3D 0 && addr >=3D 0xfffffff0 && is_exec) { - cpu->exception_index =3D EXCP_EXCEPTION_EXIT; - cpu_loop_exit(cpu); - } - - /* In real hardware an attempt to access parts of the address space - * with nothing there will usually cause an external abort. - * However our QEMU board models are often missing device models where - * the guest can boot anyway with the default read-as-zero/writes-igno= red - * behaviour that you get without a QEMU unassigned_access hook. - * So just return here to retain that default behaviour. - */ -} - static bool arm_v7m_cpu_exec_interrupt(CPUState *cs, int interrupt_request) { CPUClass *cc =3D CPU_GET_CLASS(cs); @@ -338,17 +311,7 @@ static bool arm_v7m_cpu_exec_interrupt(CPUState *cs, i= nt interrupt_request) CPUARMState *env =3D &cpu->env; bool ret =3D false; =20 - /* ARMv7-M interrupt return works by loading a magic value - * into the PC. On real hardware the load causes the - * return to occur. The qemu implementation performs the - * jump normally, then does the exception return when the - * CPU tries to execute code at the magic address. - * This will cause the magic PC value to be pushed to - * the stack if an interrupt occurred at the wrong time. - * We avoid this by disabling interrupts when - * pc contains a magic address. - * - * ARMv7-M interrupt masking works differently than -A or -R. + /* ARMv7-M interrupt masking works differently than -A or -R. * There is no FIQ/IRQ distinction. Instead of I and F bits * masking FIQ and IRQ interrupts, an exception is taken only * if it is higher priority than the current execution priority @@ -356,8 +319,7 @@ static bool arm_v7m_cpu_exec_interrupt(CPUState *cs, in= t interrupt_request) * currently active exception). */ if (interrupt_request & CPU_INTERRUPT_HARD - && (armv7m_nvic_can_take_pending_exception(env->nvic)) - && (env->regs[15] < 0xfffffff0)) { + && (armv7m_nvic_can_take_pending_exception(env->nvic))) { cs->exception_index =3D EXCP_IRQ; cc->do_interrupt(cs); ret =3D true; @@ -1091,7 +1053,6 @@ static void arm_v7m_class_init(ObjectClass *oc, void = *data) cc->do_interrupt =3D arm_v7m_cpu_do_interrupt; #endif =20 - cc->do_unassigned_access =3D arm_v7m_unassigned_access; cc->cpu_exec_interrupt =3D arm_v7m_cpu_exec_interrupt; } =20 diff --git a/target/arm/translate.c b/target/arm/translate.c index da03e153..0b5a0bc 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -11927,14 +11927,6 @@ void gen_intermediate_code(CPUARMState *env, Trans= lationBlock *tb) dc->is_jmp =3D DISAS_EXC; break; } -#else - if (arm_dc_feature(dc, ARM_FEATURE_M)) { - /* Branches to the magic exception-return addresses should - * already have been caught via the arm_v7m_unassigned_access = hook, - * and never get here. - */ - assert(dc->pc < 0xfffffff0); - } #endif =20 if (unlikely(!QTAILQ_EMPTY(&cs->breakpoints))) { --=20 2.7.4