Richard Henderson <richard.hender...@linaro.org> writes:
> For aarch64, there's a dedicated msr (imm, reg) insn. > For aarch32, this is done via msr to cpsr; and writes > from el0 are ignored. > > Since v8.0, the CPSR_RESERVED bits have been allocated. > We are not yet implementing ARMv8.0-SSBS or ARMv8.4-DIT, > so retain CPSR_RESERVED for now, so that the bits remain RES0. > > Signed-off-by: Richard Henderson <richard.hender...@linaro.org> Reviewed-by: Alex Bennée <alex.ben...@linaro.org> > --- > v2: Move regdef to file scope; merge patch for CPSR_RESERVED: > do not remove CPSR_SSBS from CPSR_RESERVED yet, mask PAN > from CPSR if feature not enabled (pmm). > --- > target/arm/cpu.h | 11 +++++++++-- > target/arm/helper-a64.c | 6 ++++++ > target/arm/helper.c | 21 +++++++++++++++++++++ > target/arm/op_helper.c | 9 ++++++++- > target/arm/translate-a64.c | 14 ++++++++++++++ > target/arm/translate.c | 6 +++++- > 6 files changed, 63 insertions(+), 4 deletions(-) > > diff --git a/target/arm/cpu.h b/target/arm/cpu.h > index 08b2f5d73e..b11fdc3001 100644 > --- a/target/arm/cpu.h > +++ b/target/arm/cpu.h > @@ -1186,12 +1186,18 @@ void pmu_init(ARMCPU *cpu); > #define CPSR_IT_2_7 (0xfc00U) > #define CPSR_GE (0xfU << 16) > #define CPSR_IL (1U << 20) > -/* Note that the RESERVED bits include bit 21, which is PSTATE_SS in > +/* > + * Note that the RESERVED bits include bit 21, which is PSTATE_SS in > * an AArch64 SPSR but RES0 in AArch32 SPSR and CPSR. In QEMU we use > * env->uncached_cpsr bit 21 to store PSTATE.SS when executing in AArch32, > * where it is live state but not accessible to the AArch32 code. > + * > + * TODO: With ARMv8.4-DIT, bit 21 is DIT in AArch32 (bit 24 for AArch64). > + * We will need to move AArch32 SS somewhere else at that point. > + * TODO: With ARMv8.0-SSBS, bit 23 is SSBS in AArch32 (bit 12 for AArch64). > */ > -#define CPSR_RESERVED (0x7U << 21) > +#define CPSR_RESERVED (5U << 21) > +#define CPSR_PAN (1U << 22) > #define CPSR_J (1U << 24) > #define CPSR_IT_0_1 (3U << 25) > #define CPSR_Q (1U << 27) > @@ -1258,6 +1264,7 @@ void pmu_init(ARMCPU *cpu); > #define PSTATE_BTYPE (3U << 10) > #define PSTATE_IL (1U << 20) > #define PSTATE_SS (1U << 21) > +#define PSTATE_PAN (1U << 22) > #define PSTATE_V (1U << 28) > #define PSTATE_C (1U << 29) > #define PSTATE_Z (1U << 30) > diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c > index bf45f8a785..70d6407f80 100644 > --- a/target/arm/helper-a64.c > +++ b/target/arm/helper-a64.c > @@ -1014,6 +1014,9 @@ void HELPER(exception_return)(CPUARMState *env, > uint64_t new_pc) > * will sort the register banks out for us, and we've already > * caught all the bad-mode cases in el_from_spsr(). > */ > + if (!cpu_isar_feature(aa32_pan, env_archcpu(env))) { > + spsr &= ~CPSR_PAN; > + } > cpsr_write(env, spsr, ~0, CPSRWriteRaw); > if (!arm_singlestep_active(env)) { > env->uncached_cpsr &= ~PSTATE_SS; > @@ -1031,6 +1034,9 @@ void HELPER(exception_return)(CPUARMState *env, > uint64_t new_pc) > cur_el, new_el, env->regs[15]); > } else { > env->aarch64 = 1; > + if (!cpu_isar_feature(aa64_pan, env_archcpu(env))) { > + spsr &= ~PSTATE_PAN; > + } > pstate_write(env, spsr); > if (!arm_singlestep_active(env)) { > env->pstate &= ~PSTATE_SS; > diff --git a/target/arm/helper.c b/target/arm/helper.c > index 795ef727d0..90a22921dc 100644 > --- a/target/arm/helper.c > +++ b/target/arm/helper.c > @@ -4163,6 +4163,24 @@ static void aa64_daif_write(CPUARMState *env, const > ARMCPRegInfo *ri, > env->daif = value & PSTATE_DAIF; > } > > +static uint64_t aa64_pan_read(CPUARMState *env, const ARMCPRegInfo *ri) > +{ > + return env->pstate & PSTATE_PAN; > +} > + > +static void aa64_pan_write(CPUARMState *env, const ARMCPRegInfo *ri, > + uint64_t value) > +{ > + env->pstate = (env->pstate & ~PSTATE_PAN) | (value & PSTATE_PAN); > +} > + > +static const ARMCPRegInfo pan_reginfo = { > + .name = "PAN", .state = ARM_CP_STATE_AA64, > + .opc0 = 3, .opc1 = 0, .crn = 4, .crm = 2, .opc2 = 3, > + .type = ARM_CP_NO_RAW, .access = PL1_RW, > + .readfn = aa64_pan_read, .writefn = aa64_pan_write > +}; > + > static CPAccessResult aa64_cacheop_access(CPUARMState *env, > const ARMCPRegInfo *ri, > bool isread) > @@ -7608,6 +7626,9 @@ void register_cp_regs_for_features(ARMCPU *cpu) > if (cpu_isar_feature(aa64_lor, cpu)) { > define_arm_cp_regs(cpu, lor_reginfo); > } > + if (cpu_isar_feature(aa64_pan, cpu)) { > + define_one_arm_cp_reg(cpu, &pan_reginfo); > + } > > if (arm_feature(env, ARM_FEATURE_EL2) && cpu_isar_feature(aa64_vh, cpu)) > { > define_arm_cp_regs(cpu, vhe_reginfo); > diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c > index 27d16ad9ad..7ba578e826 100644 > --- a/target/arm/op_helper.c > +++ b/target/arm/op_helper.c > @@ -400,11 +400,18 @@ void HELPER(cpsr_write)(CPUARMState *env, uint32_t val, > uint32_t mask) > /* Write the CPSR for a 32-bit exception return */ > void HELPER(cpsr_write_eret)(CPUARMState *env, uint32_t val) > { > + uint32_t mask; > + > qemu_mutex_lock_iothread(); > arm_call_pre_el_change_hook(env_archcpu(env)); > qemu_mutex_unlock_iothread(); > > - cpsr_write(env, val, CPSR_ERET_MASK, CPSRWriteExceptionReturn); > + mask = CPSR_ERET_MASK; > + if (!cpu_isar_feature(aa32_pan, env_archcpu(env))) { > + mask &= ~CPSR_PAN; > + } > + > + cpsr_write(env, val, mask, CPSRWriteExceptionReturn); > > /* Generated code has already stored the new PC value, but > * without masking out its low bits, because which bits need > diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c > index 49631c2340..d8ba240a15 100644 > --- a/target/arm/translate-a64.c > +++ b/target/arm/translate-a64.c > @@ -1602,6 +1602,20 @@ static void handle_msr_i(DisasContext *s, uint32_t > insn, > s->base.is_jmp = DISAS_NEXT; > break; > > + case 0x04: /* PAN */ > + if (!dc_isar_feature(aa64_pan, s) || s->current_el == 0) { > + goto do_unallocated; > + } > + if (crm & 1) { > + set_pstate_bits(PSTATE_PAN); > + } else { > + clear_pstate_bits(PSTATE_PAN); > + } > + t1 = tcg_const_i32(s->current_el); > + gen_helper_rebuild_hflags_a64(cpu_env, t1); > + tcg_temp_free_i32(t1); > + break; > + > case 0x05: /* SPSel */ > if (s->current_el == 0) { > goto do_unallocated; > diff --git a/target/arm/translate.c b/target/arm/translate.c > index d58c328e08..0b1f0e0fea 100644 > --- a/target/arm/translate.c > +++ b/target/arm/translate.c > @@ -2760,13 +2760,17 @@ static uint32_t msr_mask(DisasContext *s, int flags, > int spsr) > if (!arm_dc_feature(s, ARM_FEATURE_THUMB2)) { > mask &= ~CPSR_IT; > } > + if (!dc_isar_feature(aa32_pan, s)) { > + mask &= ~CPSR_PAN; > + } > /* Mask out execution state and reserved bits. */ > if (!spsr) { > mask &= ~(CPSR_EXEC | CPSR_RESERVED); > } > /* Mask out privileged bits. */ > - if (IS_USER(s)) > + if (IS_USER(s)) { > mask &= CPSR_USER; > + } > return mask; > } -- Alex Bennée