From 2ed08180db096ea5e44573529b85e09b1ed10b08 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Wed, 24 Oct 2018 07:50:18 +0100 Subject: [PATCH] target/arm: Get IL bit correct for v7 syndrome values For the v7 version of the Arm architecture, the IL bit in syndrome register values where the field is not valid was defined to be UNK/SBZP. In v8 this is RES1, which is what QEMU currently implements. Handle the desired v7 behaviour by squashing the IL bit for the affected cases: * EC == EC_UNCATEGORIZED * prefetch aborts * data aborts where ISV is 0 (The fourth case listed in the v8 Arm ARM DDI 0487C.a in section G7.2.70, "illegal state exception", can't happen on a v7 CPU.) This deals with a corner case noted in a comment. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20181012144235.19646-10-peter.maydell@linaro.org --- target/arm/helper.c | 13 +++++++++++++ target/arm/internals.h | 7 ++----- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index 87f66b818c..e4e231de19 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -8302,6 +8302,19 @@ static void arm_cpu_do_interrupt_aarch32_hyp(CPUState *cs) } if (cs->exception_index != EXCP_IRQ && cs->exception_index != EXCP_FIQ) { + if (!arm_feature(env, ARM_FEATURE_V8)) { + /* + * QEMU syndrome values are v8-style. v7 has the IL bit + * UNK/SBZP for "field not valid" cases, where v8 uses RES1. + * If this is a v7 CPU, squash the IL bit in those cases. + */ + if (cs->exception_index == EXCP_PREFETCH_ABORT || + (cs->exception_index == EXCP_DATA_ABORT && + !(env->exception.syndrome & ARM_EL_ISV)) || + syn_get_ec(env->exception.syndrome) == EC_UNCATEGORIZED) { + env->exception.syndrome &= ~ARM_EL_IL; + } + } env->cp15.esr_el[2] = env->exception.syndrome; } diff --git a/target/arm/internals.h b/target/arm/internals.h index bf7bd1fbfe..6b9387ba97 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -286,11 +286,8 @@ static inline uint32_t syn_get_ec(uint32_t syn) /* Utility functions for constructing various kinds of syndrome value. * Note that in general we follow the AArch64 syndrome values; in a * few cases the value in HSR for exceptions taken to AArch32 Hyp - * mode differs slightly, so if we ever implemented Hyp mode then the - * syndrome value would need some massaging on exception entry. - * (One example of this is that AArch64 defaults to IL bit set for - * exceptions which don't specifically indicate information about the - * trapping instruction, whereas AArch32 defaults to IL bit clear.) + * mode differs slightly, and we fix this up when populating HSR in + * arm_cpu_do_interrupt_aarch32_hyp(). */ static inline uint32_t syn_uncategorized(void) {