Re: [RFC PATCH 12/15] hw/m68k: Restrict M68kCPU type to target/ code

["Philippe Mathieu-Daudé via" <qemu-devel@nongnu.org>]

On 9/2/22 23:50, Richard Henderson wrote:
> On 2/10/22 08:54, Philippe Mathieu-Daudé wrote:
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>   include/hw/m68k/mcf.h | 3 +--
>>   target/m68k/cpu-qom.h | 2 --
>>   target/m68k/cpu.h     | 4 ++--
>>   3 files changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/hw/m68k/mcf.h b/include/hw/m68k/mcf.h
>> index 8cbd587bbf..e84fcfb4ca 100644
>> --- a/include/hw/m68k/mcf.h
>> +++ b/include/hw/m68k/mcf.h
>> @@ -3,7 +3,6 @@
>>   /* Motorola ColdFire device prototypes.  */
>>   #include "exec/hwaddr.h"
>> -#include "target/m68k/cpu-qom.h"
>>   /* mcf_uart.c */
>>   uint64_t mcf_uart_read(void *opaque, hwaddr addr,
>> @@ -16,7 +15,7 @@ void mcf_uart_mm_init(hwaddr base, qemu_irq irq, 
>> Chardev *chr);
>>   /* mcf_intc.c */
>>   qemu_irq *mcf_intc_init(struct MemoryRegion *sysmem,
>>                           hwaddr base,
>> -                        M68kCPU *cpu);
>> +                        ArchCPU *cpu);
>>   /* mcf5206.c */
>>   #define TYPE_MCF5206_MBAR "mcf5206-mbar"
> 
> This part is ok.
> 
>> diff --git a/target/m68k/cpu-qom.h b/target/m68k/cpu-qom.h
>> index c2c0736b3b..ec75adad69 100644
>> --- a/target/m68k/cpu-qom.h
>> +++ b/target/m68k/cpu-qom.h
>> @@ -25,8 +25,6 @@
>>   #define TYPE_M68K_CPU "m68k-cpu"
>> -typedef struct ArchCPU M68kCPU;
>> -
>>   OBJECT_DECLARE_TYPE(ArchCPU, M68kCPUClass,
>>                       M68K_CPU)
>> diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
>> index 872e8ce637..90be69e714 100644
>> --- a/target/m68k/cpu.h
>> +++ b/target/m68k/cpu.h
>> @@ -156,14 +156,14 @@ typedef struct CPUArchState {
>>    *
>>    * A Motorola 68k CPU.
>>    */
>> -struct ArchCPU {
>> +typedef struct ArchCPU {
>>       /*< private >*/
>>       CPUState parent_obj;
>>       /*< public >*/
>>       CPUNegativeOffsetState neg;
>>       CPUM68KState env;
>> -};
>> +} M68kCPU;
> 
> I don't like these.  Rationale?

Short-term idea: hw/ models only have access to cpu-qom.h declarations
and opaque pointers to generic CPU objects.

hw/ should not include cpu.h at all. By restricting FooCPU to target/
code, hw/ files fail to compile if using FooCPU and not ArchCPU.


Long-term idea, each target/ is built as a module, exposing an uniform
arch-API.

I'm still prototyping to see how to disentangle arch-specific hw which
access CPU internals (such ARM NVIC or MIPS ITU).