Re: [PATCH] target/arm: Allow loading elf from aliased ROM regions

[Richard Henderson]

On 11/25/19 12:41 PM, Jean-Hugues Deschênes wrote:
>              initial_msp = ldl_p(rom);
>              initial_pc = ldl_p(rom + 4);
>          } else {
> -            /* Address zero not covered by a ROM blob, or the ROM blob
> -             * is in non-modifiable memory and this is a second reset after
> -             * it got copied into memory. In the latter case, rom_ptr
> -             * will return a NULL pointer and we should use ldl_phys instead.
> -             */
> -            initial_msp = ldl_phys(s->as, vecbase);
> -            initial_pc = ldl_phys(s->as, vecbase + 4);
> +            /* See if the ROM blob is aliased somewhere */
> +            hwaddr len = 0, xlat = 0;
> +            MemoryRegion *mr = address_space_translate(s->as, vecbase, &xlat,
> +                    &len, false, MEMTXATTRS_UNSPECIFIED);
> +
> +            if (mr) {
> +                rom = rom_ptr(mr->addr + xlat, 8);
> +            } else {
> +                rom = NULL;
> +            }
> +
> +            if (rom) {
> +                initial_msp = ldl_p(rom);
> +                initial_pc = ldl_p(rom + 4);
> +            } else {
> +
> +                /*
> +                 * Address zero not covered by a ROM blob, or the ROM blob
> +                 * is in non-modifiable memory and this is a second reset 
> after
> +                 * it got copied into memory. In the latter case, rom_ptr
> +                 * will return a NULL pointer and we should use ldl_phys
> +                 * instead.
> +                 */
> +                initial_msp = ldl_phys(s->as, vecbase);
> +                initial_pc = ldl_phys(s->as, vecbase + 4);
> +            }
>          }

Can this entire section, including the rom_ptr thing just above, be replaced
with two address_space_read()?


r~