Re: [Qemu-devel] [PATCH v2 3/6] target/s390x: Diagnose specification exception for atomics

[Aurelien Jarno]

On 2017-05-08 08:17, Richard Henderson wrote:
> All of the interlocked access facility instructions raise a
> specification exception for unaligned accesses.  Do this by
> using the (previously unused) unaligned_access hook.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/s390x/cpu.c    |  1 +
>  target/s390x/cpu.h    |  3 +++
>  target/s390x/helper.c | 16 ++++++++++++++++
>  3 files changed, 20 insertions(+)
> 
> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
> index 066dcd1..a1bf2ba 100644
> --- a/target/s390x/cpu.c
> +++ b/target/s390x/cpu.c
> @@ -430,6 +430,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void 
> *data)
>      cc->write_elf64_note = s390_cpu_write_elf64_note;
>      cc->cpu_exec_interrupt = s390_cpu_exec_interrupt;
>      cc->debug_excp_handler = s390x_cpu_debug_excp_handler;
> +    cc->do_unaligned_access = s390x_cpu_do_unaligned_access;
>  #endif
>      cc->disas_set_info = s390_cpu_disas_set_info;
>  
> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index 058ddad..bbed320 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -480,6 +480,9 @@ int s390_cpu_handle_mmu_fault(CPUState *cpu, vaddr 
> address, int rw,
>  
>  #ifndef CONFIG_USER_ONLY
>  void do_restart_interrupt(CPUS390XState *env);
> +void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> +                                   MMUAccessType access_type,
> +                                   int mmu_idx, uintptr_t retaddr);
>  
>  static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb,
>                                         uint8_t *ar)
> diff --git a/target/s390x/helper.c b/target/s390x/helper.c
> index 68bd2f9..9978490 100644
> --- a/target/s390x/helper.c
> +++ b/target/s390x/helper.c
> @@ -718,4 +718,20 @@ void s390x_cpu_debug_excp_handler(CPUState *cs)
>          cpu_loop_exit_noexc(cs);
>      }
>  }
> +
> +/* Unaligned accesses are only diagnosed with MO_ALIGN.  At the moment,
> +   this is only for the atomic operations, for which we want to raise a
> +   specification exception.  */
> +void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> +                                   MMUAccessType access_type,
> +                                   int mmu_idx, uintptr_t retaddr)
> +{
> +    S390CPU *cpu = S390_CPU(cs);
> +    CPUS390XState *env = &cpu->env;
> +
> +    if (retaddr) {
> +        cpu_restore_state(cs, retaddr);
> +    }
> +    program_interrupt(env, PGM_SPECIFICATION, ILEN_LATER);
> +}
>  #endif /* CONFIG_USER_ONLY */

Reviewed-by: Aurelien Jarno <address@hidden>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
address@hidden                 http://www.aurel32.net