From patchwork Thu Feb 16 16:36:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 94092 Delivered-To: patches@linaro.org Received: by 10.140.20.99 with SMTP id 90csp2585595qgi; Thu, 16 Feb 2017 08:36:09 -0800 (PST) X-Received: by 10.25.25.8 with SMTP id 8mr1076527lfz.164.1487262969589; Thu, 16 Feb 2017 08:36:09 -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 e81si1115783lff.67.2017.02.16.08.36.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Feb 2017 08:36:09 -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 1ceP2O-00035c-PL; Thu, 16 Feb 2017 16:36:08 +0000 From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: patches@linaro.org, =?utf-8?q?Alex_Benn=C3=A9e?= Subject: [PATCH v2 10/13] armv7m: Extract "exception taken" code into functions Date: Thu, 16 Feb 2017 16:36:00 +0000 Message-Id: <1487262963-11519-11-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487262963-11519-1-git-send-email-peter.maydell@linaro.org> References: <1487262963-11519-1-git-send-email-peter.maydell@linaro.org> Extract the code from the tail end of arm_v7m_do_interrupt() which enters the exception handler into a pair of utility functions v7m_exception_taken() and v7m_push_stack(), which correspond roughly to the pseudocode PushStack() and ExceptionTaken(). This also requires us to move the arm_v7m_load_vector() utility routine up so we can call it. Handling illegal exception returns has some cases where we want to take a UsageFault either on an existing stack frame or with a new stack frame but with a specific LR value, so we want to be able to call these without having to go via arm_v7m_cpu_do_interrupt(). Signed-off-by: Peter Maydell --- target/arm/helper.c | 118 ++++++++++++++++++++++++++++++---------------------- 1 file changed, 68 insertions(+), 50 deletions(-) -- 2.7.4 Reviewed-by: Alex Bennée Reviewed-by: Philippe Mathieu-Daudé diff --git a/target/arm/helper.c b/target/arm/helper.c index 1844852..f94d1c7 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -6001,6 +6001,72 @@ static void switch_v7m_sp(CPUARMState *env, bool new_spsel) } } +static uint32_t arm_v7m_load_vector(ARMCPU *cpu) +{ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + MemTxResult result; + hwaddr vec = env->v7m.vecbase + env->v7m.exception * 4; + uint32_t addr; + + addr = address_space_ldl(cs->as, vec, + MEMTXATTRS_UNSPECIFIED, &result); + if (result != MEMTX_OK) { + /* Architecturally this should cause a HardFault setting HSFR.VECTTBL, + * which would then be immediately followed by our failing to load + * the entry vector for that HardFault, which is a Lockup case. + * Since we don't model Lockup, we just report this guest error + * via cpu_abort(). + */ + cpu_abort(cs, "Failed to read from exception vector table " + "entry %08x\n", (unsigned)vec); + } + return addr; +} + +static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr) +{ + /* Do the "take the exception" parts of exception entry, + * but not the pushing of state to the stack. This is + * similar to the pseudocode ExceptionTaken() function. + */ + CPUARMState *env = &cpu->env; + uint32_t addr; + + armv7m_nvic_acknowledge_irq(env->nvic); + switch_v7m_sp(env, 0); + /* Clear IT bits */ + env->condexec_bits = 0; + env->regs[14] = lr; + addr = arm_v7m_load_vector(cpu); + env->regs[15] = addr & 0xfffffffe; + env->thumb = addr & 1; +} + +static void v7m_push_stack(ARMCPU *cpu) +{ + /* Do the "set up stack frame" part of exception entry, + * similar to pseudocode PushStack(). + */ + CPUARMState *env = &cpu->env; + uint32_t xpsr = xpsr_read(env); + + /* Align stack pointer if the guest wants that */ + if ((env->regs[13] & 4) && (env->v7m.ccr & R_V7M_CCR_STKALIGN_MASK)) { + env->regs[13] -= 4; + xpsr |= 0x200; + } + /* Switch to the handler mode. */ + v7m_push(env, xpsr); + v7m_push(env, env->regs[15]); + v7m_push(env, env->regs[14]); + v7m_push(env, env->regs[12]); + v7m_push(env, env->regs[3]); + v7m_push(env, env->regs[2]); + v7m_push(env, env->regs[1]); + v7m_push(env, env->regs[0]); +} + static void do_v7m_exception_exit(CPUARMState *env) { uint32_t type; @@ -6062,37 +6128,11 @@ static void arm_log_exception(int idx) } } -static uint32_t arm_v7m_load_vector(ARMCPU *cpu) - -{ - CPUState *cs = CPU(cpu); - CPUARMState *env = &cpu->env; - MemTxResult result; - hwaddr vec = env->v7m.vecbase + env->v7m.exception * 4; - uint32_t addr; - - addr = address_space_ldl(cs->as, vec, - MEMTXATTRS_UNSPECIFIED, &result); - if (result != MEMTX_OK) { - /* Architecturally this should cause a HardFault setting HSFR.VECTTBL, - * which would then be immediately followed by our failing to load - * the entry vector for that HardFault, which is a Lockup case. - * Since we don't model Lockup, we just report this guest error - * via cpu_abort(). - */ - cpu_abort(cs, "Failed to read from exception vector table " - "entry %08x\n", (unsigned)vec); - } - return addr; -} - void arm_v7m_cpu_do_interrupt(CPUState *cs) { ARMCPU *cpu = ARM_CPU(cs); CPUARMState *env = &cpu->env; - uint32_t xpsr = xpsr_read(env); uint32_t lr; - uint32_t addr; arm_log_exception(cs->exception_index); @@ -6150,31 +6190,9 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs) return; /* Never happens. Keep compiler happy. */ } - armv7m_nvic_acknowledge_irq(env->nvic); - + v7m_push_stack(cpu); + v7m_exception_taken(cpu, lr); qemu_log_mask(CPU_LOG_INT, "... as %d\n", env->v7m.exception); - - /* Align stack pointer if the guest wants that */ - if ((env->regs[13] & 4) && (env->v7m.ccr & R_V7M_CCR_STKALIGN_MASK)) { - env->regs[13] -= 4; - xpsr |= 0x200; - } - /* Switch to the handler mode. */ - v7m_push(env, xpsr); - v7m_push(env, env->regs[15]); - v7m_push(env, env->regs[14]); - v7m_push(env, env->regs[12]); - v7m_push(env, env->regs[3]); - v7m_push(env, env->regs[2]); - v7m_push(env, env->regs[1]); - v7m_push(env, env->regs[0]); - switch_v7m_sp(env, 0); - /* Clear IT bits */ - env->condexec_bits = 0; - env->regs[14] = lr; - addr = arm_v7m_load_vector(cpu); - env->regs[15] = addr & 0xfffffffe; - env->thumb = addr & 1; } /* Function used to synchronize QEMU's AArch64 register set with AArch32