pci: initialize BAR config on demand only

On-demand initialization prevents read-write operations on BARs of
invalid devices at construction time, which may result in surprising
behavior later on, for example, when resetting X260 notebooks via ACPI
information.
This commit is contained in:
Christian Helmuth 2022-10-07 17:10:05 +02:00
parent ba97415ef9
commit e7ba0b7371

View File

@ -104,34 +104,43 @@ struct Pci::Config : Genode::Mmio
struct Upper_bits : Register<0x4, 32> { }; struct Upper_bits : Register<0x4, 32> { };
Bar_32bit::access_t _conf { 0 }; Bar_32bit::access_t _conf_value { 0 };
Base_address(Genode::addr_t base) : Mmio(base) Bar_32bit::access_t _conf()
{ {
Bar_32bit::access_t v = read<Bar_32bit>(); /*
write<Bar_32bit>(0xffffffff); * Initialize _conf_value on demand only to prevent read-write
_conf = read<Bar_32bit>(); * operations on BARs of invalid devices at construction time.
write<Bar_32bit>(v); */
if (!_conf_value) {
Bar_32bit::access_t v = read<Bar_32bit>();
write<Bar_32bit>(0xffffffff);
_conf_value = read<Bar_32bit>();
write<Bar_32bit>(v);
}
return _conf_value;
} }
bool valid() { return _conf != 0; } Base_address(Genode::addr_t base) : Mmio(base) { }
bool valid() { return _conf() != 0; }
bool memory() { bool memory() {
return !Bar_32bit::Memory_space_indicator::get(_conf); } return !Bar_32bit::Memory_space_indicator::get(_conf()); }
bool bit64() bool bit64()
{ {
return Bar_32bit::Memory_type::get(_conf) == return Bar_32bit::Memory_type::get(_conf()) ==
Bar_32bit::Memory_type::SIZE_64BIT; Bar_32bit::Memory_type::SIZE_64BIT;
} }
bool prefetchable() { bool prefetchable() {
return Bar_32bit::Memory_prefetchable::get(_conf); } return Bar_32bit::Memory_prefetchable::get(_conf()); }
Genode::size_t size() Genode::size_t size()
{ {
return 1 + (memory() ? ~Bar_32bit::Memory_base::masked(_conf) return 1 + (memory() ? ~Bar_32bit::Memory_base::masked(_conf())
: ~Bar_32bit::Io_base::masked(_conf)); : ~Bar_32bit::Io_base::masked(_conf()));
} }
Genode::uint64_t addr() Genode::uint64_t addr()