Messages in this thread | | | Date | Mon, 15 Aug 2016 12:54:14 +0100 | From | Matt Fleming <> | Subject | Re: [PATCH 0/6] Apple device properties |
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On Tue, 09 Aug, at 03:38:16PM, Lukas Wunner wrote: > @@ -208,7 +201,10 @@ struct efi_config { > __pure const struct efi_config *__efi_early(void); > > #define efi_call_early(f, ...) \ > - __efi_early()->call(__efi_early()->f, __VA_ARGS__); > + __efi_early()->call(__efi_early()->is64 ? \ > + ((efi_boot_services_64_t *)__efi_early()->boot_services)->f : \ > + ((efi_boot_services_32_t *)__efi_early()->boot_services)->f, \ > + __VA_ARGS__); >
You cannot use pointers from the firmware directly in mixed mode because the kernel is compiled for 64-bits but the firmware is using 32-bit addresses, so dereferencing a pointer causes a 64-bit load.
That's the reason we deconstruct the tables and copy the addresses from the last level - so we don't have to jump through multiple pointers.
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