From patchwork Thu Feb 2 20:02:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 93131 Delivered-To: patches@linaro.org Received: by 10.140.20.99 with SMTP id 90csp272614qgi; Thu, 2 Feb 2017 12:02:26 -0800 (PST) X-Received: by 10.25.195.76 with SMTP id t73mr3060696lff.40.1486065746681; Thu, 02 Feb 2017 12:02:26 -0800 (PST) Return-Path: Received: from orth.archaic.org.uk (orth.archaic.org.uk. [2001:8b0:1d0::2]) by mx.google.com with ESMTPS id h89si14926078lji.51.2017.02.02.12.02.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Feb 2017 12:02:26 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 2001:8b0:1d0::2 as permitted sender) client-ip=2001:8b0:1d0::2; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 2001:8b0:1d0::2 as permitted sender) smtp.mailfrom=pm215@archaic.org.uk; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1cZNaL-0001vE-H0; Thu, 02 Feb 2017 20:02:25 +0000 From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: patches@linaro.org, =?utf-8?q?Alex_Benn=C3=A9e?= , Michael Davidsaver , Liviu Ionescu Subject: [PATCH 4/9] armv7m: Fix condition check for taking exceptions Date: Thu, 2 Feb 2017 20:02:17 +0000 Message-Id: <1486065742-28639-5-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1486065742-28639-1-git-send-email-peter.maydell@linaro.org> References: <1486065742-28639-1-git-send-email-peter.maydell@linaro.org> The M profile condition for when we can take a pending exception or interrupt is not the same as that for A/R profile. The code originally copied from the A/R profile version of the cpu_exec_interrupt function only worked by chance for the very simple case of exceptions being masked by PRIMASK. Replace it with a call to a function in the NVIC code that correctly compares the priority of the pending exception against the current execution priority of the CPU. [Michael Davidsaver's patchset had a patch to do something similar but the implementation ended up being a rewrite.] Signed-off-by: Peter Maydell --- target/arm/cpu.h | 8 ++++++++ hw/intc/armv7m_nvic.c | 7 +++++++ target/arm/cpu.c | 16 ++++++++-------- 3 files changed, 23 insertions(+), 8 deletions(-) -- 2.7.4 Reviewed-by: Alex Bennée diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 39bff86..ac20a56 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -1335,6 +1335,14 @@ uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t excp_idx, uint32_t cur_el, bool secure); /* Interface between CPU and Interrupt controller. */ +#ifndef CONFIG_USER_ONLY +bool armv7m_nvic_can_take_pending_exception(void *opaque); +#else +static inline bool armv7m_nvic_can_take_pending_exception(void *opaque) +{ + return true; +} +#endif void armv7m_nvic_set_pending(void *opaque, int irq); int armv7m_nvic_acknowledge_irq(void *opaque); void armv7m_nvic_complete_irq(void *opaque, int irq); diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c index e319077..3d77cbf 100644 --- a/hw/intc/armv7m_nvic.c +++ b/hw/intc/armv7m_nvic.c @@ -268,6 +268,13 @@ static inline int nvic_exec_prio(NVICState *s) return MIN(running, s->exception_prio); } +bool armv7m_nvic_can_take_pending_exception(void *opaque) +{ + NVICState *s = opaque; + + return nvic_exec_prio(s) > nvic_pending_prio(s); +} + /* caller must call nvic_irq_update() after this */ static void set_prio(NVICState *s, unsigned irq, uint8_t prio) { diff --git a/target/arm/cpu.c b/target/arm/cpu.c index e9f10f7..7713d88 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -338,13 +338,6 @@ static bool arm_v7m_cpu_exec_interrupt(CPUState *cs, int interrupt_request) CPUARMState *env = &cpu->env; bool ret = false; - - if (interrupt_request & CPU_INTERRUPT_FIQ - && !(env->daif & PSTATE_F)) { - cs->exception_index = EXCP_FIQ; - cc->do_interrupt(cs); - ret = true; - } /* 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 @@ -354,9 +347,16 @@ static bool arm_v7m_cpu_exec_interrupt(CPUState *cs, int interrupt_request) * 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. + * 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 + * (which depends on state like BASEPRI, FAULTMASK and the + * currently active exception). */ if (interrupt_request & CPU_INTERRUPT_HARD - && !(env->daif & PSTATE_I) + && (armv7m_nvic_can_take_pending_exception(env->nvic)) && (env->regs[15] < 0xfffffff0)) { cs->exception_index = EXCP_IRQ; cc->do_interrupt(cs);