Remove TARGET_BIG_ENDIAN dependency.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
---
 target/arm/cpu.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index e7a15ade8b4..85e886944f6 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -67,6 +67,15 @@ static void arm_cpu_set_pc(CPUState *cs, vaddr value)
     }
 }
 
+static bool arm_cpu_is_big_endian(CPUState *cs)
+{
+    ARMCPU *cpu = ARM_CPU(cs);
+    CPUARMState *env = &cpu->env;
+
+    cpu_synchronize_state(cs);
+    return arm_cpu_data_is_big_endian(env);
+}
+
 static vaddr arm_cpu_get_pc(CPUState *cs)
 {
     ARMCPU *cpu = ARM_CPU(cs);
@@ -1130,15 +1139,6 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, int level)
 #endif
 }
 
-static bool arm_cpu_virtio_is_big_endian(CPUState *cs)
-{
-    ARMCPU *cpu = ARM_CPU(cs);
-    CPUARMState *env = &cpu->env;
-
-    cpu_synchronize_state(cs);
-    return arm_cpu_data_is_big_endian(env);
-}
-
 #ifdef CONFIG_TCG
 bool arm_cpu_exec_halt(CPUState *cs)
 {
@@ -1203,7 +1203,7 @@ static void arm_disas_set_info(CPUState *cpu, disassemble_info *info)
 
     info->endian = BFD_ENDIAN_LITTLE;
     if (bswap_code(sctlr_b)) {
-        info->endian = TARGET_BIG_ENDIAN ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
+        info->endian = arm_cpu_is_big_endian(cpu) ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
     }
     info->flags &= ~INSN_ARM_BE32;
 #ifndef CONFIG_USER_ONLY
@@ -2681,7 +2681,7 @@ static const struct SysemuCPUOps arm_sysemu_ops = {
     .asidx_from_attrs = arm_asidx_from_attrs,
     .write_elf32_note = arm_cpu_write_elf32_note,
     .write_elf64_note = arm_cpu_write_elf64_note,
-    .virtio_is_big_endian = arm_cpu_virtio_is_big_endian,
+    .virtio_is_big_endian = arm_cpu_is_big_endian,
     .legacy_vmsd = &vmstate_arm_cpu,
 };
 #endif
-- 
2.47.2

On 29/04/25, Pierrick Bouvier wrote:
> Remove TARGET_BIG_ENDIAN dependency.
> 
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>  target/arm/cpu.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index e7a15ade8b4..85e886944f6 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -67,6 +67,15 @@ static void arm_cpu_set_pc(CPUState *cs, vaddr value)
>      }
>  }
>  
> +static bool arm_cpu_is_big_endian(CPUState *cs)
> +{
> +    ARMCPU *cpu = ARM_CPU(cs);
> +    CPUARMState *env = &cpu->env;
> +
> +    cpu_synchronize_state(cs);
> +    return arm_cpu_data_is_big_endian(env);
> +}
> +
>  static vaddr arm_cpu_get_pc(CPUState *cs)
>  {
>      ARMCPU *cpu = ARM_CPU(cs);
> @@ -1130,15 +1139,6 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, int level)
>  #endif
>  }
>  
> -static bool arm_cpu_virtio_is_big_endian(CPUState *cs)
> -{
> -    ARMCPU *cpu = ARM_CPU(cs);
> -    CPUARMState *env = &cpu->env;
> -
> -    cpu_synchronize_state(cs);
> -    return arm_cpu_data_is_big_endian(env);
> -}
> -
>  #ifdef CONFIG_TCG
>  bool arm_cpu_exec_halt(CPUState *cs)
>  {
> @@ -1203,7 +1203,7 @@ static void arm_disas_set_info(CPUState *cpu, disassemble_info *info)
>  
>      info->endian = BFD_ENDIAN_LITTLE;
>      if (bswap_code(sctlr_b)) {
> -        info->endian = TARGET_BIG_ENDIAN ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
> +        info->endian = arm_cpu_is_big_endian(cpu) ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
>      }

I'm not the most familiar with arm but as far as I can tell these are
not equivalent. My understanding is that arm_cpu_is_big_endian() models
data endianness, and TARGET_BIG_ENDIAN instruction endianness.

Also, for user mode where this branch is relevant, bswap_code() still
depends on TARGET_BIG_ENDIAN anyway and the above branch would reduce to
(on arm32)

  if (TARGET_BIG_ENDIAN ^ sctlr_b) {
      info->endian = sctlr_b ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
  }

giving the opposite result to the original code.

-- 
Anton Johansson
rev.ng Labs Srl.

On 4/29/25 5:26 AM, Anton Johansson wrote:
> On 29/04/25, Pierrick Bouvier wrote:
>> Remove TARGET_BIG_ENDIAN dependency.
>>
>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
>> ---
>>   target/arm/cpu.c | 22 +++++++++++-----------
>>   1 file changed, 11 insertions(+), 11 deletions(-)
>>
>> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
>> index e7a15ade8b4..85e886944f6 100644
>> --- a/target/arm/cpu.c
>> +++ b/target/arm/cpu.c
>> @@ -67,6 +67,15 @@ static void arm_cpu_set_pc(CPUState *cs, vaddr value)
>>       }
>>   }
>>   
>> +static bool arm_cpu_is_big_endian(CPUState *cs)
>> +{
>> +    ARMCPU *cpu = ARM_CPU(cs);
>> +    CPUARMState *env = &cpu->env;
>> +
>> +    cpu_synchronize_state(cs);
>> +    return arm_cpu_data_is_big_endian(env);
>> +}
>> +
>>   static vaddr arm_cpu_get_pc(CPUState *cs)
>>   {
>>       ARMCPU *cpu = ARM_CPU(cs);
>> @@ -1130,15 +1139,6 @@ static void arm_cpu_kvm_set_irq(void *opaque, int irq, int level)
>>   #endif
>>   }
>>   
>> -static bool arm_cpu_virtio_is_big_endian(CPUState *cs)
>> -{
>> -    ARMCPU *cpu = ARM_CPU(cs);
>> -    CPUARMState *env = &cpu->env;
>> -
>> -    cpu_synchronize_state(cs);
>> -    return arm_cpu_data_is_big_endian(env);
>> -}
>> -
>>   #ifdef CONFIG_TCG
>>   bool arm_cpu_exec_halt(CPUState *cs)
>>   {
>> @@ -1203,7 +1203,7 @@ static void arm_disas_set_info(CPUState *cpu, disassemble_info *info)
>>   
>>       info->endian = BFD_ENDIAN_LITTLE;
>>       if (bswap_code(sctlr_b)) {
>> -        info->endian = TARGET_BIG_ENDIAN ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
>> +        info->endian = arm_cpu_is_big_endian(cpu) ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
>>       }
> 
> I'm not the most familiar with arm but as far as I can tell these are
> not equivalent. My understanding is that arm_cpu_is_big_endian() models
> data endianness, and TARGET_BIG_ENDIAN instruction endianness.
> 
> Also, for user mode where this branch is relevant, bswap_code() still
> depends on TARGET_BIG_ENDIAN anyway and the above branch would reduce to
> (on arm32)
> 
>    if (TARGET_BIG_ENDIAN ^ sctlr_b) {
>        info->endian = sctlr_b ? BFD_ENDIAN_LITTLE : BFD_ENDIAN_BIG;
>    }
> 
> giving the opposite result to the original code.
> 

Ooops, that's a good point, I missed it was calling 
arm_cpu_data_is_big_endian under the hoods.

I'll stick to target_big_endian().

Thanks,
Pierrick