Re: [Qemu-devel] [PATCH v2 16/23] target-arm: Use arm_current_sctlr to access SCTLR

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Tue, May 13, 2014 at 06:16:01PM +0200, Fabian Aggeler wrote:
> Add SCTLR_EL3 and introduce new function to access correct
> instance of SCTLR in different modes/worlds.

Hi,

AArch64 has a couple of insn/regs that do address translation
as seen by other ELs. E.g, from EL3 you can perform address
translation as seen by EL0. See for example ATS12E0R.
AArch32 has similar features, it can also lower S to NS when in S mode.

With regards to arm_current_sctlr() and the use in get_phys_addr, I
don't think it is enough here.

I was planning to post was patches that add new args to get_phys_addr()
with the translation-EL and flags to control if stage-2 translation
should be done or not. That way ats_write() can keep reusing
get_phys_addr(). We would need to pass the security state as an argument
aswell to handle AArch32. Does that make sense?

Cheers,
Edgar

> 
> Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
> ---
>  hw/arm/pxa2xx.c        |  2 +-
>  target-arm/cpu-qom.h   |  1 +
>  target-arm/cpu.c       |  4 +--
>  target-arm/cpu.h       | 14 ++++++++++-
>  target-arm/helper.c    | 67 ++++++++++++++++++++++++++++++++++++++------------
>  target-arm/op_helper.c |  2 +-
>  6 files changed, 69 insertions(+), 21 deletions(-)
> 
> diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
> index e0cd847..8b69e72 100644
> --- a/hw/arm/pxa2xx.c
> +++ b/hw/arm/pxa2xx.c
> @@ -274,7 +274,7 @@ static void pxa2xx_pwrmode_write(CPUARMState *env, const ARMCPRegInfo *ri,
>      case 3:
>          s->cpu->env.uncached_cpsr = ARM_CPU_MODE_SVC;
>          s->cpu->env.daif = PSTATE_A | PSTATE_F | PSTATE_I;
> -        s->cpu->env.cp15.c1_sys = 0;
> +        s->cpu->env.cp15.c1_sys_el1 = 0;
>          s->cpu->env.cp15.c1_coproc = 0;
>          s->cpu->env.cp15.ttbr0_el1 = 0;
>          s->cpu->env.cp15.c3 = 0;
> diff --git a/target-arm/cpu-qom.h b/target-arm/cpu-qom.h
> index edc7f26..38cbd43 100644
> --- a/target-arm/cpu-qom.h
> +++ b/target-arm/cpu-qom.h
> @@ -119,6 +119,7 @@ typedef struct ARMCPU {
>      uint32_t mvfr2;
>      uint32_t ctr;
>      uint32_t reset_sctlr;
> +    uint32_t reset_sctlr_el3;
>      uint32_t id_pfr0;
>      uint32_t id_pfr1;
>      uint32_t id_dfr0;
> diff --git a/target-arm/cpu.c b/target-arm/cpu.c
> index b0d4a9b..bdbdbb1 100644
> --- a/target-arm/cpu.c
> +++ b/target-arm/cpu.c
> @@ -100,7 +100,7 @@ static void arm_cpu_reset(CPUState *s)
>  #if defined(CONFIG_USER_ONLY)
>          env->pstate = PSTATE_MODE_EL0t;
>          /* Userspace expects access to CTL_EL0 and the cache ops */
> -        env->cp15.c1_sys |= SCTLR_UCT | SCTLR_UCI;
> +        env->cp15.c1_sys_el1 |= SCTLR_UCT | SCTLR_UCI;
>          /* and to the FP/Neon instructions */
>          env->cp15.c1_coproc = deposit64(env->cp15.c1_coproc, 20, 2, 3);
>  #else
> @@ -146,7 +146,7 @@ static void arm_cpu_reset(CPUState *s)
>          }
>      }
>  
> -    if (env->cp15.c1_sys & SCTLR_V) {
> +    if (arm_current_sctlr(env) & SCTLR_V) {
>              env->regs[15] = 0xFFFF0000;
>      }
>  
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index a4bb6bd..780c1f5 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -180,7 +180,8 @@ typedef struct CPUARMState {
>      struct {
>          uint32_t c0_cpuid;
>          uint64_t c0_cssel; /* Cache size selection.  */
> -        uint64_t c1_sys; /* System control register.  */
> +        uint64_t c1_sys_el1; /* System control register (EL1). */
> +        uint64_t c1_sys_el3; /* System control register (EL3).  */
>          uint64_t c1_coproc; /* Coprocessor access register.  */
>          uint32_t c1_xscaleauxcr; /* XScale auxiliary control register.  */
>          uint32_t c1_scr; /* secure config register.  */
> @@ -971,6 +972,17 @@ static inline int arm_current_pl(CPUARMState *env)
>      return 1;
>  }
>  
> +static inline uint64_t arm_current_sctlr(CPUARMState *env)
> +{
> +    if (is_a64(env) && arm_current_pl(env) == 3) {
> +        /* EL3 has its own SCTLR */
> +        return env->cp15.c1_sys_el3;
> +    } else {
> +        /* Only A32 with NS-bit clear accesses secure instance of SCTLR */
> +        return A32_MAPPED_EL3_REG_GET(env, c1_sys);
> +    }
> +}
> +
>  typedef struct ARMCPRegInfo ARMCPRegInfo;
>  
>  typedef enum CPAccessResult {
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 98c3dc9..ac8b15a 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -1767,7 +1767,7 @@ static void aa64_fpsr_write(CPUARMState *env, const ARMCPRegInfo *ri,
>  
>  static CPAccessResult aa64_daif_access(CPUARMState *env, const ARMCPRegInfo *ri)
>  {
> -    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UMA)) {
> +    if (arm_current_pl(env) == 0 && !(arm_current_sctlr(env) & SCTLR_UMA)) {
>          return CP_ACCESS_TRAP;
>      }
>      return CP_ACCESS_OK;
> @@ -1785,7 +1785,7 @@ static CPAccessResult aa64_cacheop_access(CPUARMState *env,
>      /* Cache invalidate/clean: NOP, but EL0 must UNDEF unless
>       * SCTLR_EL1.UCI is set.
>       */
> -    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UCI)) {
> +    if (arm_current_pl(env) == 0 && !(arm_current_sctlr(env) & SCTLR_UCI)) {
>          return CP_ACCESS_TRAP;
>      }
>      return CP_ACCESS_OK;
> @@ -1823,7 +1823,7 @@ static CPAccessResult aa64_zva_access(CPUARMState *env, const ARMCPRegInfo *ri)
>      /* We don't implement EL2, so the only control on DC ZVA is the
>       * bit in the SCTLR which can prohibit access for EL0.
>       */
> -    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_DZE)) {
> +    if (arm_current_pl(env) == 0 && !(arm_current_sctlr(env) & SCTLR_DZE)) {
>          return CP_ACCESS_TRAP;
>      }
>      return CP_ACCESS_OK;
> @@ -2146,7 +2146,7 @@ static CPAccessResult ctr_el0_access(CPUARMState *env, const ARMCPRegInfo *ri)
>      /* Only accessible in EL0 if SCTLR.UCT is set (and only in AArch64,
>       * but the AArch32 CTR has its own reginfo struct)
>       */
> -    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UCT)) {
> +    if (arm_current_pl(env) == 0 && !(arm_current_sctlr(env) & SCTLR_UCT)) {
>          return CP_ACCESS_TRAP;
>      }
>      return CP_ACCESS_OK;
> @@ -2573,10 +2573,11 @@ void register_cp_regs_for_features(ARMCPU *cpu)
>  
>      /* Generic registers whose values depend on the implementation */
>      {
> -        ARMCPRegInfo sctlr = {
> -            .name = "SCTLR", .state = ARM_CP_STATE_BOTH,
> -            .opc0 = 3, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
> -            .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c1_sys),
> +        ARMCPRegInfo sctlr_el1 = {
> +            .name = "SCTLR_EL1", .state = ARM_CP_STATE_BOTH,
> +            .type = ARM_CP_NONSECURE, .opc0 = 3, .crn = 1, .crm = 0, .opc1 = 0,
> +            .opc2 = 0, .access = PL1_RW,
> +            .fieldoffset = offsetof(CPUARMState, cp15.c1_sys_el1),
>              .writefn = sctlr_write, .resetvalue = cpu->reset_sctlr,
>              .raw_writefn = raw_write,
>          };
> @@ -2585,9 +2586,43 @@ void register_cp_regs_for_features(ARMCPU *cpu)
>               * arch/arm/mach-pxa/sleep.S expects two instructions following
>               * an MMU enable to execute from cache.  Imitate this behaviour.
>               */
> -            sctlr.type |= ARM_CP_SUPPRESS_TB_END;
> +            sctlr_el1.type |= ARM_CP_SUPPRESS_TB_END;
>          }
> -        define_one_arm_cp_reg(cpu, &sctlr);
> +        define_one_arm_cp_reg(cpu, &sctlr_el1);
> +
> +        ARMCPRegInfo sctlr_el1_s = {
> +            .name = "SCTLR_EL1(S)", .type = ARM_CP_SECURE,
> +            .cp = 15, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
> +            .access = PL3_RW,
> +            .fieldoffset = offsetof(CPUARMState, cp15.c1_sys_el3),
> +            .writefn = sctlr_write, .resetvalue = cpu->reset_sctlr,
> +            .raw_writefn = raw_write,
> +        };
> +        if (arm_feature(env, ARM_FEATURE_XSCALE)) {
> +            /* Normally we would always end the TB on an SCTLR write, but Linux
> +             * arch/arm/mach-pxa/sleep.S expects two instructions following
> +             * an MMU enable to execute from cache.  Imitate this behaviour.
> +             */
> +            sctlr_el1_s.type |= ARM_CP_SUPPRESS_TB_END;
> +        }
> +        define_one_arm_cp_reg(cpu, &sctlr_el1_s);
> +
> +        ARMCPRegInfo sctlr_el3 = {
> +             .name = "SCTLR_EL3", .state = ARM_CP_STATE_AA64,
> +             .opc0 = 3, .crn = 1, .crm = 0, .opc1 = 6, .opc2 = 0,
> +             .access = PL3_RW, .type = ARM_CP_SECURE,
> +             .fieldoffset = offsetof(CPUARMState, cp15.c1_sys_el3),
> +             .writefn = sctlr_write, .resetvalue = cpu->reset_sctlr_el3,
> +             .raw_writefn = raw_write,
> +        };
> +        if (arm_feature(env, ARM_FEATURE_XSCALE)) {
> +            /* Normally we would always end the TB on an SCTLR write, but Linux
> +             * arch/arm/mach-pxa/sleep.S expects two instructions following
> +             * an MMU enable to execute from cache.  Imitate this behaviour.
> +             */
> +            sctlr_el3.type |= ARM_CP_SUPPRESS_TB_END;
> +        }
> +        define_one_arm_cp_reg(cpu, &sctlr_el3);
>      }
>  }
>  
> @@ -3475,7 +3510,7 @@ void arm_cpu_do_interrupt(CPUState *cs)
>          return; /* Never happens.  Keep compiler happy.  */
>      }
>      /* High vectors.  */
> -    if (env->cp15.c1_sys & SCTLR_V) {
> +    if (arm_current_sctlr(env) & SCTLR_V) {
>          /* when enabled, base address cannot be remapped.  */
>          addr += 0xffff0000;
>      } else {
> @@ -3498,7 +3533,7 @@ void arm_cpu_do_interrupt(CPUState *cs)
>      /* 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 = (env->cp15.c1_sys & SCTLR_TE) != 0;
> +        env->thumb = (arm_current_sctlr(env) & SCTLR_TE) != 0;
>      }
>      env->regs[14] = env->regs[15] + offset;
>      env->regs[15] = addr;
> @@ -3529,7 +3564,7 @@ static inline int check_ap(CPUARMState *env, int ap, int domain_prot,
>        }
>        if (access_type == 1)
>            return 0;
> -      switch (env->cp15.c1_sys & (SCTLR_S | SCTLR_R)) {
> +      switch (arm_current_sctlr(env) & (SCTLR_S | SCTLR_R)) {
>        case SCTLR_S:
>            return is_user ? 0 : PAGE_READ;
>        case SCTLR_R:
> @@ -3763,7 +3798,7 @@ static int get_phys_addr_v6(CPUARMState *env, uint32_t address, int access_type,
>              goto do_fault;
>  
>          /* The simplified model uses AP[0] as an access control bit.  */
> -        if ((env->cp15.c1_sys & SCTLR_AFE) && (ap & 1) == 0) {
> +        if ((arm_current_sctlr(env) & SCTLR_AFE) && (ap & 1) == 0) {
>              /* Access flag fault.  */
>              code = (code == 15) ? 6 : 3;
>              goto do_fault;
> @@ -4099,7 +4134,7 @@ static inline int get_phys_addr(CPUARMState *env, target_ulong address,
>      if (address < 0x02000000)
>          address += env->cp15.c13_fcse;
>  
> -    if ((env->cp15.c1_sys & SCTLR_M) == 0) {
> +    if ((arm_current_sctlr(env) & SCTLR_M) == 0) {
>          /* MMU/MPU disabled.  */
>          *phys_ptr = address;
>          *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
> @@ -4112,7 +4147,7 @@ static inline int get_phys_addr(CPUARMState *env, target_ulong address,
>      } else if (extended_addresses_enabled(env)) {
>          return get_phys_addr_lpae(env, address, access_type, is_user, phys_ptr,
>                                    prot, page_size);
> -    } else if (env->cp15.c1_sys & SCTLR_XP) {
> +    } else if (arm_current_sctlr(env) & SCTLR_XP) {
>          return get_phys_addr_v6(env, address, access_type, is_user, phys_ptr,
>                                  prot, page_size);
>      } else {
> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> index fb90676..3eacea8 100644
> --- a/target-arm/op_helper.c
> +++ b/target-arm/op_helper.c
> @@ -365,7 +365,7 @@ void HELPER(msr_i_pstate)(CPUARMState *env, uint32_t op, uint32_t imm)
>       * Note that SPSel is never OK from EL0; we rely on handle_msr_i()
>       * to catch that case at translate time.
>       */
> -    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UMA)) {
> +    if (arm_current_pl(env) == 0 && !(arm_current_sctlr(env) & SCTLR_UMA)) {
>          raise_exception(env, EXCP_UDEF);
>      }
>  
> -- 
> 1.8.3.2
>