On Tue, Aug 14, 2018 at 01:42:54PM +0100, Peter Maydell wrote: > Implement the necessary support code for taking exceptions > to Hyp mode in AArch32.
Hi Peter, A general comment that I think this would be a little easier to look at if it was split into two patches, one non-functional change to break-out take_aarch32_exception() and then another patch to add the new logic... Another comment inline below > > Signed-off-by: Peter Maydell <[email protected]> > --- > target/arm/helper.c | 146 +++++++++++++++++++++++++++++++++++++------- > 1 file changed, 123 insertions(+), 23 deletions(-) > > diff --git a/target/arm/helper.c b/target/arm/helper.c > index 80855302089..167203ac664 100644 > --- a/target/arm/helper.c > +++ b/target/arm/helper.c > @@ -8013,6 +8013,123 @@ void aarch64_sync_64_to_32(CPUARMState *env) > env->regs[15] = env->pc; > } > > +static void take_aarch32_exception(CPUARMState *env, int new_mode, > + uint32_t mask, uint32_t offset, > + uint32_t newpc) > +{ > + /* Change the CPU state so as to actually take the exception. */ > + switch_mode(env, new_mode); > + /* > + * For exceptions taken to AArch32 we must clear the SS bit in both > + * PSTATE and in the old-state value we save to SPSR_<mode>, so zero it > now. > + */ > + env->uncached_cpsr &= ~PSTATE_SS; > + env->spsr = cpsr_read(env); > + /* Clear IT bits. */ > + env->condexec_bits = 0; > + /* Switch to the new mode, and to the correct instruction set. */ > + env->uncached_cpsr = (env->uncached_cpsr & ~CPSR_M) | new_mode; > + /* Set new mode endianness */ > + env->uncached_cpsr &= ~CPSR_E; > + if (env->cp15.sctlr_el[arm_current_el(env)] & SCTLR_EE) { > + env->uncached_cpsr |= CPSR_E; > + } > + env->daif |= mask; > + > + if (new_mode == ARM_CPU_MODE_HYP) { > + env->thumb = (env->cp15.sctlr_el[2] & SCTLR_TE) != 0; > + env->elr_el[2] = env->regs[15]; > + } else { > + /* > + * this is a lie, as there was no c1_sys on V4T/V5, but who cares > + * and we should just guard the thumb mode on V4 > + */ > + if (arm_feature(env, ARM_FEATURE_V4T)) { > + env->thumb = > + (A32_BANKED_CURRENT_REG_GET(env, sctlr) & SCTLR_TE) != 0; > + } > + env->regs[14] = env->regs[15] + offset; > + } > + env->regs[15] = newpc; > +} > + > +static void arm_cpu_do_interrupt_aarch32_hyp(CPUState *cs) > +{ > + /* > + * Handle exception entry to Hyp mode; this is sufficiently > + * different to entry to other AArch32 modes that we handle it > + * separately here. > + * > + * The vector table entry used is always the 0x14 Hyp mode entry point, > + * unless this is an UNDEF/HVC/abort taken from Hyp to Hyp. > + * The offset applied to the preferred return address is always zero > + * (see DDI0487C.a section G1.12.3). > + * PSTATE A/I/F masks are set based only on the SCR.EA/IRQ/FIQ values. > + */ > + uint32_t addr, mask; > + ARMCPU *cpu = ARM_CPU(cs); > + CPUARMState *env = &cpu->env; > + > + switch (cs->exception_index) { > + case EXCP_UDEF: > + addr = 0x04; > + break; > + case EXCP_SWI: > + addr = 0x14; > + break; > + case EXCP_BKPT: > + /* Fall through to prefetch abort. */ > + case EXCP_PREFETCH_ABORT: > + env->cp15.ifar_s = env->exception.vaddress; > + qemu_log_mask(CPU_LOG_INT, "...with HIFAR 0x%x\n", > + (uint32_t)env->exception.vaddress); > + addr = 0x0c; > + break; > + case EXCP_DATA_ABORT: > + env->cp15.dfar_s = env->exception.vaddress; > + qemu_log_mask(CPU_LOG_INT, "...with HDFAR 0x%x\n", > + (uint32_t)env->exception.vaddress); > + addr = 0x10; > + break; > + case EXCP_IRQ: > + addr = 0x18; > + break; > + case EXCP_FIQ: > + addr = 0x1c; > + break; > + case EXCP_HVC: > + addr = 0x08; > + break; > + case EXCP_HYP_TRAP: > + addr = 0x14; > + default: > + cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index); > + } > + > + if (cs->exception_index != EXCP_IRQ && cs->exception_index != EXCP_FIQ) { > + env->cp15.esr_el[2] = env->exception.syndrome; > + } > + > + if (arm_current_el(env) != 2 && addr < 0x14) { > + addr = 0x14; > + } > + > + mask = 0; > + if (!(env->cp15.scr_el3 & SCR_EA)) { > + mask |= CPSR_A; > + } > + if (!(env->cp15.scr_el3 & SCR_IRQ)) { > + mask |= CPSR_I; > + } > + if (!(env->cp15.scr_el3 & SCR_IRQ)) {a ^^^^^^^ I think this should test for SCR_FIQ. Other than those two comments I think this looks OK! Thanks, Edgar > + mask |= CPSR_F; > + } > + > + addr += env->cp15.hvbar; > + > + take_aarch32_exception(env, ARM_CPU_MODE_HYP, mask, 0, addr); > +} > + > static void arm_cpu_do_interrupt_aarch32(CPUState *cs) > { > ARMCPU *cpu = ARM_CPU(cs); > @@ -8048,6 +8165,11 @@ static void arm_cpu_do_interrupt_aarch32(CPUState *cs) > env->cp15.mdscr_el1 = deposit64(env->cp15.mdscr_el1, 2, 4, moe); > } > > + if (env->exception.target_el == 2) { > + arm_cpu_do_interrupt_aarch32_hyp(cs); > + return; > + } > + > /* TODO: Vectored interrupt controller. */ > switch (cs->exception_index) { > case EXCP_UDEF: > @@ -8155,29 +8277,7 @@ static void arm_cpu_do_interrupt_aarch32(CPUState *cs) > env->cp15.scr_el3 &= ~SCR_NS; > } > > - switch_mode (env, new_mode); > - /* For exceptions taken to AArch32 we must clear the SS bit in both > - * PSTATE and in the old-state value we save to SPSR_<mode>, so zero it > now. > - */ > - env->uncached_cpsr &= ~PSTATE_SS; > - env->spsr = cpsr_read(env); > - /* Clear IT bits. */ > - env->condexec_bits = 0; > - /* Switch to the new mode, and to the correct instruction set. */ > - env->uncached_cpsr = (env->uncached_cpsr & ~CPSR_M) | new_mode; > - /* Set new mode endianness */ > - env->uncached_cpsr &= ~CPSR_E; > - if (env->cp15.sctlr_el[arm_current_el(env)] & SCTLR_EE) { > - env->uncached_cpsr |= CPSR_E; > - } > - env->daif |= mask; > - /* this is a lie, as the was no c1_sys on V4T/V5, but who cares > - * and we should just guard the thumb mode on V4 */ > - if (arm_feature(env, ARM_FEATURE_V4T)) { > - env->thumb = (A32_BANKED_CURRENT_REG_GET(env, sctlr) & SCTLR_TE) != > 0; > - } > - env->regs[14] = env->regs[15] + offset; > - env->regs[15] = addr; > + take_aarch32_exception(env, new_mode, mask, offset, addr); > } > > /* Handle exception entry to a target EL which is using AArch64 */ > -- > 2.18.0 >
