Re: [Qemu-devel] [PATCH 04/14] target-arm: Move setting of exception info into tlb_fill

[Edgar E. Iglesias]

On Tue, May 19, 2015 at 07:33:24PM +0100, Peter Maydell wrote:
> Move the code which sets exception information out of
> arm_cpu_handle_mmu_fault and into tlb_fill. tlb_fill
> is the only caller which wants to raise_exception()
> so it makes more sense for it to handle the whole of
> the exception setup.
> 
> As part of this cleanup, move the user-mode-only
> implementation function for the handle_mmu_fault CPU
> method into cpu.c so we don't need to make it globally
> visible, and rename the softmmu-only utility function
> arm_cpu_handle_mmu_fault to arm_tlb_fill so it's clear
> that it's not the same thing.

Reviewed-by: Edgar E. Iglesias <address@hidden>


> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target-arm/cpu.c       | 17 +++++++++++++++++
>  target-arm/cpu.h       |  2 --
>  target-arm/helper.c    | 47 +++++++----------------------------------------
>  target-arm/internals.h |  3 +++
>  target-arm/op_helper.c | 27 +++++++++++++++++++++++++--
>  5 files changed, 52 insertions(+), 44 deletions(-)
> 
> diff --git a/target-arm/cpu.c b/target-arm/cpu.c
> index 3ca3fa8..798c689 100644
> --- a/target-arm/cpu.c
> +++ b/target-arm/cpu.c
> @@ -1197,6 +1197,23 @@ static Property arm_cpu_properties[] = {
>      DEFINE_PROP_END_OF_LIST()
>  };
>  
> +#ifdef CONFIG_USER_ONLY
> +static int arm_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int rw,
> +                                    int mmu_idx)
> +{
> +    ARMCPU *cpu = ARM_CPU(cs);
> +    CPUARMState *env = &cpu->env;
> +
> +    env->exception.vaddress = address;
> +    if (rw == 2) {
> +        cs->exception_index = EXCP_PREFETCH_ABORT;
> +    } else {
> +        cs->exception_index = EXCP_DATA_ABORT;
> +    }
> +    return 1;
> +}
> +#endif
> +
>  static void arm_cpu_class_init(ObjectClass *oc, void *data)
>  {
>      ARMCPUClass *acc = ARM_CPU_CLASS(oc);
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index 75d6c4c..6845666 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -504,8 +504,6 @@ static inline bool is_a64(CPUARMState *env)
>     is returned if the signal was handled by the virtual CPU.  */
>  int cpu_arm_signal_handler(int host_signum, void *pinfo,
>                             void *puc);
> -int arm_cpu_handle_mmu_fault(CPUState *cpu, vaddr address, int rw,
> -                             int mmu_idx);
>  
>  /**
>   * pmccntr_sync
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 5d0f011..a9e85b9 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -4047,21 +4047,6 @@ uint32_t HELPER(rbit)(uint32_t x)
>  
>  #if defined(CONFIG_USER_ONLY)
>  
> -int arm_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int rw,
> -                             int mmu_idx)
> -{
> -    ARMCPU *cpu = ARM_CPU(cs);
> -    CPUARMState *env = &cpu->env;
> -
> -    env->exception.vaddress = address;
> -    if (rw == 2) {
> -        cs->exception_index = EXCP_PREFETCH_ABORT;
> -    } else {
> -        cs->exception_index = EXCP_DATA_ABORT;
> -    }
> -    return 1;
> -}
> -
>  /* These should probably raise undefined insn exceptions.  */
>  void HELPER(v7m_msr)(CPUARMState *env, uint32_t reg, uint32_t val)
>  {
> @@ -5826,8 +5811,12 @@ static inline int get_phys_addr(CPUARMState *env, 
> target_ulong address,
>      }
>  }
>  
> -int arm_cpu_handle_mmu_fault(CPUState *cs, vaddr address,
> -                             int access_type, int mmu_idx)
> +/* Walk the page table and (if the mapping exists) add the page
> + * to the TLB. Return 0 on success, or an ARM DFSR/IFSR fault
> + * register format value on failure.
> + */
> +int arm_tlb_fill(CPUState *cs, vaddr address,
> +                 int access_type, int mmu_idx)
>  {
>      ARMCPU *cpu = ARM_CPU(cs);
>      CPUARMState *env = &cpu->env;
> @@ -5835,8 +5824,6 @@ int arm_cpu_handle_mmu_fault(CPUState *cs, vaddr 
> address,
>      target_ulong page_size;
>      int prot;
>      int ret;
> -    uint32_t syn;
> -    bool same_el = (arm_current_el(env) != 0);
>      MemTxAttrs attrs = {};
>  
>      ret = get_phys_addr(env, address, access_type, mmu_idx, &phys_addr,
> @@ -5850,27 +5837,7 @@ int arm_cpu_handle_mmu_fault(CPUState *cs, vaddr 
> address,
>          return 0;
>      }
>  
> -    /* AArch64 syndrome does not have an LPAE bit */
> -    syn = ret & ~(1 << 9);
> -
> -    /* For insn and data aborts we assume there is no instruction syndrome
> -     * information; this is always true for exceptions reported to EL1.
> -     */
> -    if (access_type == 2) {
> -        syn = syn_insn_abort(same_el, 0, 0, syn);
> -        cs->exception_index = EXCP_PREFETCH_ABORT;
> -    } else {
> -        syn = syn_data_abort(same_el, 0, 0, 0, access_type == 1, syn);
> -        if (access_type == 1 && arm_feature(env, ARM_FEATURE_V6)) {
> -            ret |= (1 << 11);
> -        }
> -        cs->exception_index = EXCP_DATA_ABORT;
> -    }
> -
> -    env->exception.syndrome = syn;
> -    env->exception.vaddress = address;
> -    env->exception.fsr = ret;
> -    return 1;
> +    return ret;
>  }
>  
>  hwaddr arm_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
> diff --git a/target-arm/internals.h b/target-arm/internals.h
> index de0a9c1..1e5071e 100644
> --- a/target-arm/internals.h
> +++ b/target-arm/internals.h
> @@ -387,4 +387,7 @@ bool arm_is_psci_call(ARMCPU *cpu, int excp_type);
>  void arm_handle_psci_call(ARMCPU *cpu);
>  #endif
>  
> +/* Do a page table walk and add page to TLB if possible */
> +int arm_tlb_fill(CPUState *cpu, vaddr address, int rw, int mmu_idx);
> +
>  #endif
> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> index 5af4a0e..cda9767 100644
> --- a/target-arm/op_helper.c
> +++ b/target-arm/op_helper.c
> @@ -80,16 +80,39 @@ void tlb_fill(CPUState *cs, target_ulong addr, int 
> is_write, int mmu_idx,
>  {
>      int ret;
>  
> -    ret = arm_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
> +    ret = arm_tlb_fill(cs, addr, is_write, mmu_idx);
>      if (unlikely(ret)) {
>          ARMCPU *cpu = ARM_CPU(cs);
>          CPUARMState *env = &cpu->env;
> +        uint32_t syn, exc;
> +        bool same_el = (arm_current_el(env) != 0);
>  
>          if (retaddr) {
>              /* now we have a real cpu fault */
>              cpu_restore_state(cs, retaddr);
>          }
> -        raise_exception(env, cs->exception_index);
> +
> +        /* AArch64 syndrome does not have an LPAE bit */
> +        syn = ret & ~(1 << 9);
> +
> +        /* For insn and data aborts we assume there is no instruction 
> syndrome
> +         * information; this is always true for exceptions reported to EL1.
> +         */
> +        if (is_write == 2) {
> +            syn = syn_insn_abort(same_el, 0, 0, syn);
> +            exc = EXCP_PREFETCH_ABORT;
> +        } else {
> +            syn = syn_data_abort(same_el, 0, 0, 0, is_write == 1, syn);
> +            if (is_write == 1 && arm_feature(env, ARM_FEATURE_V6)) {
> +                ret |= (1 << 11);
> +            }
> +            exc = EXCP_DATA_ABORT;
> +        }
> +
> +        env->exception.syndrome = syn;
> +        env->exception.vaddress = addr;
> +        env->exception.fsr = ret;
> +        raise_exception(env, exc);
>      }
>  }
>  #endif
> -- 
> 1.9.1
>