On 6 October 2014 10:46, Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 30 September 2014 22:49, Greg Bellows <greg.bell...@linaro.org> wrote:
> > From: Fabian Aggeler <aggel...@ethz.ch>
> >
> > Implements SMC instruction in Aarch32 using the A32 syndrome. When
> executing
> > SMC instruction from monitor CPU mode SCR.NS bit is reset.
> >
> > Signed-off-by: Sergey Fedorov <s.fedo...@samsung.com>
> > Signed-off-by: Fabian Aggeler <aggel...@ethz.ch>
> > Signed-off-by: Greg Bellows <greg.bell...@linaro.org>
> >
> > ----------
> > v4 -> v5
> > - Merge pre_smc upstream changes and incorporated ss_advance
> > ---
> > target-arm/helper.c | 11 +++++++++++
> > target-arm/internals.h | 7 ++++++-
> > target-arm/op_helper.c | 3 +--
> > target-arm/translate.c | 39 +++++++++++++++++++++++++++++----------
> > 4 files changed, 47 insertions(+), 13 deletions(-)
> >
> > diff --git a/target-arm/helper.c b/target-arm/helper.c
> > index 2381e6f..7f3f049 100644
> > --- a/target-arm/helper.c
> > +++ b/target-arm/helper.c
> > @@ -4090,6 +4090,12 @@ void arm_cpu_do_interrupt(CPUState *cs)
> > mask = CPSR_A | CPSR_I | CPSR_F;
> > offset = 4;
> > break;
> > + case EXCP_SMC:
> > + new_mode = ARM_CPU_MODE_MON;
> > + addr = 0x08;
> > + mask = CPSR_A | CPSR_I | CPSR_F;
> > + offset = 0;
> > + break;
> > default:
> > cpu_abort(cs, "Unhandled exception 0x%x\n",
> cs->exception_index);
> > return; /* Never happens. Keep compiler happy. */
> > @@ -4108,6 +4114,11 @@ void arm_cpu_do_interrupt(CPUState *cs)
> > */
> > addr += env->cp15.vbar_el[1];
> > }
> > +
> > + if ((env->uncached_cpsr & CPSR_M) == ARM_CPU_MODE_MON) {
> > + 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.
> > diff --git a/target-arm/internals.h b/target-arm/internals.h
> > index fd69a83..43a2e7d 100644
> > --- a/target-arm/internals.h
> > +++ b/target-arm/internals.h
> > @@ -236,7 +236,12 @@ static inline uint32_t syn_aa32_svc(uint32_t imm16,
> bool is_thumb)
> > | (is_thumb ? 0 : ARM_EL_IL);
> > }
> >
> > -static inline uint32_t syn_aa64_bkpt(uint32_t imm16)
> > +static inline uint32_t syn_aa32_smc(void)
> > +{
> > + return (EC_AA32_SMC << ARM_EL_EC_SHIFT) | ARM_EL_IL;
> > +}
> > +
> > +static inline uint32_t syn_aa64_bkpt(uint16_t imm16)
>
> Bogus change (probably introduced by accident in a merge
> conflict fixup).
>
Fixed in v6.
>
> > {
> > return (EC_AA64_BKPT << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 &
> 0xffff);
> > }
> > diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> > index 0809d63..8ed8ee9 100644
> > --- a/target-arm/op_helper.c
> > +++ b/target-arm/op_helper.c
> > @@ -419,8 +419,7 @@ void HELPER(pre_hvc)(CPUARMState *env)
> > void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome)
> > {
> > int cur_el = arm_current_el(env);
> > - /* FIXME: Use real secure state. */
> > - bool secure = false;
> > + bool secure = arm_is_secure(env);;
>
> Doubled semicolon.
>
Fixed in v6
>
> > bool smd = env->cp15.scr_el3 & SCR_SMD;
> > /* On ARMv8 AArch32, SMD only applies to NS state.
> > * On ARMv7 SMD only applies to NS state and only if EL2 is
> available.
> > diff --git a/target-arm/translate.c b/target-arm/translate.c
> > index f6404be..3f3ddfb 100644
> > --- a/target-arm/translate.c
> > +++ b/target-arm/translate.c
> > @@ -7872,15 +7872,27 @@ static void disas_arm_insn(CPUARMState * env,
> DisasContext *s)
> > case 7:
> > {
> > int imm16 = extract32(insn, 0, 4) | (extract32(insn, 8, 12)
> << 4);
> > - /* SMC instruction (op1 == 3)
> > - and undefined instructions (op1 == 0 || op1 == 2)
> > - will trap */
> > - if (op1 != 1) {
> > + if (op1 == 1) {
> > + /* bkpt */
> > + ARCH(5);
> > + gen_exception_insn(s, 4, EXCP_BKPT,
> > + syn_aa32_bkpt(imm16, false));
> > + } else if (op1 == 3) {
> > + /* smi/smc */
> > + if (!arm_dc_feature(s, ARM_FEATURE_EL3) ||
> > + s->current_pl == 0) {
> > + goto illegal_op;
> > + }
> > + gen_set_pc_im(s, s->pc);
>
> This should be s->pc - 4, because if the pre_smc helper throws
> an UNDEF exception you want the PC to point to the SMC insn,
> not the insn after. (If the SMC executes as an SMC then the
> PC for the EXCP_SMC will be correct because of the 0 offset
> passed to gen_exception_insn below.)
>
Fixed in v6
>
> > + tmp = tcg_const_i32(syn_aa32_smc());
> > + gen_helper_pre_smc(cpu_env, tmp);
> > + tcg_temp_free_i32(tmp);
> > + gen_ss_advance(s);
> > + gen_exception_insn(s, 0, EXCP_SMC, syn_aa32_smc());
> > + break;
> > + } else {
> > goto illegal_op;
> > }
>
> That said, I have a feeling we might want to put the SMC
> handling into the end-of-loop processing for A32/T32,
> the same way we do SVC. Ard has a patch onlist which does
> that, though it is on my todo list to try to fix because
> it has its own issues...
>
I'll leave it as-is for now because it appears to work. In the meantime,
I'll hunt for Ard's patch... unless you have a pointer and can save me the
trouble.
>
> -- PMM
>
