From ad36e61ce400deaddfb07e71b13aea8a74b52550 Mon Sep 17 00:00:00 2001 From: Giacomo Travaglini Date: Tue, 19 Dec 2017 10:18:13 +0000 Subject: [PATCH] arch-arm: Don't change PSTATE in Illegal Exception return This patch fixes the Illegal Exception return handler. According to the armarm documentation, when PSTATE.IL is set to one because of an illegal exception return, PSTATE.{EL, nRW, SP} are unchanged. This means the Exception level, Execution state, and stack pointer selection do not change as a result of the return. Change-Id: I35f2fe68fb2822a54fc4a21930871eab7a1aaab4 Signed-off-by: Giacomo Travaglini Reviewed-by: Andreas Sandberg Reviewed-on: https://gem5-review.googlesource.com/8021 Maintainer: Andreas Sandberg --- src/arch/arm/insts/static_inst.cc | 10 ++++++++++ src/arch/arm/isa.cc | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/src/arch/arm/insts/static_inst.cc b/src/arch/arm/insts/static_inst.cc index aace1de2b..a7ba91e03 100644 --- a/src/arch/arm/insts/static_inst.cc +++ b/src/arch/arm/insts/static_inst.cc @@ -1018,7 +1018,17 @@ ArmStaticInst::getPSTATEFromPSR(ThreadContext *tc, CPSR cpsr, CPSR spsr) const new_cpsr.ss = 0; if (illegalExceptionReturn(tc, cpsr, spsr)) { + // If the SPSR specifies an illegal exception return, + // then PSTATE.{M, nRW, EL, SP} are unchanged and PSTATE.IL + // is set to 1. new_cpsr.il = 1; + if (cpsr.width) { + new_cpsr.mode = cpsr.mode; + } else { + new_cpsr.width = cpsr.width; + new_cpsr.el = cpsr.el; + new_cpsr.sp = cpsr.sp; + } } else { new_cpsr.il = spsr.il; if (spsr.width && badMode32((OperatingMode)(uint8_t)spsr.mode)) { diff --git a/src/arch/arm/isa.cc b/src/arch/arm/isa.cc index c917abacf..5d34e188a 100644 --- a/src/arch/arm/isa.cc +++ b/src/arch/arm/isa.cc @@ -726,7 +726,7 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc) CPSR old_cpsr = miscRegs[MISCREG_CPSR]; int old_mode = old_cpsr.mode; CPSR cpsr = val; - if (old_mode != cpsr.mode) { + if (old_mode != cpsr.mode || cpsr.il != old_cpsr.il) { getITBPtr(tc)->invalidateMiscReg(); getDTBPtr(tc)->invalidateMiscReg(); } -- 2.30.2