Re: [PATCH] sim: ppc: fix some Wpointer-sign warnings

[Mike Frysinger via Gdb-patches <gdb-patches@sourceware.org>]

On 19 May 2021 12:46, Tom de Vries wrote:
> --- a/sim/ppc/hw_memory.c
> +++ b/sim/ppc/hw_memory.c
> @@ -190,7 +190,7 @@ hw_memory_init_address(device *me)
>    if (device_find_property(me, "available") != NULL) {
>      hw_memory_chunk **curr_chunk = &hw_memory->heap;
>      int cell_nr;
> -    unsigned_cell dummy;
> +    signed_cell dummy;
>      int nr_cells = device_find_integer_array_property(me, "available", 0, &dummy);

this one is fine

> @@ -199,9 +199,9 @@ hw_memory_init_address(device *me)
>  	 cell_nr += 2) {
>        hw_memory_chunk *new_chunk = ZALLOC(hw_memory_chunk);
>        device_find_integer_array_property(me, "available", cell_nr,
> -					 &new_chunk->address);
> +					 (signed_cell *)&new_chunk->address);
>        device_find_integer_array_property(me, "available", cell_nr + 1,
> -					 &new_chunk->size);
> +					 (signed_cell *)&new_chunk->size);
> 
> --- a/sim/ppc/hw_opic.c
> +++ b/sim/ppc/hw_opic.c
> @@ -417,10 +417,12 @@ hw_opic_init_data(device *me)
>        }
>        if (!device_find_integer_array_property(me, "interrupt-ranges",
>  					      reg_nr * 2,
> -					      &opic->isu_block[isb].int_number)
> +					      (signed_cell *)
> +					        &opic->isu_block[isb].int_number)
>  	  || !device_find_integer_array_property(me, "interrupt-ranges",
>  						 reg_nr * 2 + 1,
> -						 &opic->isu_block[isb].range))
> +						 (signed_cell *)
> +						   &opic->isu_block[isb].range))

these ones i'm not sure about.  it does fix the warnings, and it doesn't
change the status quo behavior, but i don't think it's the actual fix we
would want.  if the device tree has a negative number, it'll get converted
to an unsigned number.  i haven't thought hard as to what the right fix
would look like here.

i think we'd have to look at what other device tree users are doing like
in boot loaders (e.g. u-boot) and in the linux kernel.
-mike