Στις 2020-07-10 08:38, Christoph Hellwig έγραψε:
On Thu, Jul 09, 2020 at 11:49:21PM +0300, Mike Rapoport wrote:
> +#ifndef CONFIG_GENERIC_DEVMEM_IS_ALLOWED
> +extern int devmem_is_allowed(unsigned long pfn);
> +#endif
Nit: no need for the extern here.
> +config GENERIC_LIB_DEVMEM_IS_ALLOWED
> + bool
> + select ARCH_HAS_DEVMEM_IS_ALLOWED
This seems to work the other way around from the usual Kconfig chains.
In the most cases ARCH_HAS_SOMETHING selects GENERIC_SOMETHING.
I believe nicer way would be to make
config STRICT_DEVMEM
bool "Filter access to /dev/mem"
depends on MMU && DEVMEM
depends on ARCH_HAS_DEVMEM_IS_ALLOWED ||
GENERIC_LIB_DEVMEM_IS_ALLOWED
config GENERIC_LIB_DEVMEM_IS_ALLOWED
bool
and then s/select ARCH_HAS_DEVMEM_IS_ALLOWED/select
GENERIC_LIB_DEVMEM_IS_ALLOWED/
in the arch Kconfigs and drop ARCH_HAS_DEVMEM_IS_ALLOWED in the end.
To take a step back: Is there any reason to not just always
STRICT_DEVMEM? Maybe for a few architectures that don't currently
support a strict /dev/mem the generic version isn't quite correct, but
someone selecting the option and finding the issue is the best way to
figure that out..
During prototyping / testing having full access to all physical memory
through /dev/mem is very useful. We should have it enabled by default
but leave the config option there so that users / developers can disable
it if needed IMHO.
