Re: [Qemu-devel] [PATCH v1 08/17] target-arm: cpu: Move cpu_is_big_endian to header

[Peter Maydell <peter.maydell@linaro.org>]

On 18 January 2016 at 07:12, Peter Crosthwaite
<crosthwaitepeter@gmail.com> wrote:
> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>
> There is a CPU data endianness test that is used to drive the
> virtio_big_endian test.
>
> Move this up to the header so it can be more generally used for endian
> tests. The KVM specific cpu_syncronize_state call is left behind in the
> virtio specific function.
>
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
>
>  target-arm/cpu.c | 19 +++----------------
>  target-arm/cpu.h | 19 +++++++++++++++++++
>  2 files changed, 22 insertions(+), 16 deletions(-)
>
> diff --git a/target-arm/cpu.c b/target-arm/cpu.c
> index 35a1f12..d3b73bf 100644
> --- a/target-arm/cpu.c
> +++ b/target-arm/cpu.c
> @@ -368,26 +368,13 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, int level)
>  #endif
>  }
>
> -static bool arm_cpu_is_big_endian(CPUState *cs)
> +static bool arm_cpu_virtio_is_big_endian(CPUState *cs)
>  {
>      ARMCPU *cpu = ARM_CPU(cs);
>      CPUARMState *env = &cpu->env;
> -    int cur_el;
>
>      cpu_synchronize_state(cs);
> -
> -    /* In 32bit guest endianness is determined by looking at CPSR's E bit */
> -    if (!is_a64(env)) {
> -        return (env->uncached_cpsr & CPSR_E) ? 1 : 0;
> -    }
> -
> -    cur_el = arm_current_el(env);
> -
> -    if (cur_el == 0) {
> -        return (env->cp15.sctlr_el[1] & SCTLR_E0E) != 0;
> -    }
> -
> -    return (env->cp15.sctlr_el[cur_el] & SCTLR_EE) != 0;
> +    return arm_cpu_is_big_endian(env);
>  }
>
>  #endif
> @@ -1420,7 +1407,7 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data)
>      cc->do_unaligned_access = arm_cpu_do_unaligned_access;
>      cc->get_phys_page_debug = arm_cpu_get_phys_page_debug;
>      cc->vmsd = &vmstate_arm_cpu;
> -    cc->virtio_is_big_endian = arm_cpu_is_big_endian;
> +    cc->virtio_is_big_endian = arm_cpu_virtio_is_big_endian;
>  #endif
>      cc->gdb_num_core_regs = 26;
>      cc->gdb_core_xml_file = "arm-core.xml";
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index f83070a..54675c7 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -1795,6 +1795,25 @@ static inline bool arm_singlestep_active(CPUARMState *env)
>          && arm_generate_debug_exceptions(env);
>  }
>
> +/* Return true if the processor is in big-endian mode. */
> +static bool arm_cpu_is_big_endian(CPUARMState *env)
> +{

No problems code-wise, but can we call the function
arm_cpu_data_is_big_endian() or something? This is returning the
endianness to use for data accesses; there isn't an overall
"big-endian mode" that affects everything except for the
obsolete BE32.

thanks
-- PMM