Re: [PATCH 0/6] Apple device properties
From: Matt Fleming <hidden>
Date: 2016-08-15 11:54:20
Also in:
linux-efi, lkml
Possibly related (same subject, not in this thread)
- 2016-07-28 · [PATCH 0/6] Apple device properties · Lukas Wunner <lukas@wunner.de>
On Tue, 09 Aug, at 03:38:16PM, Lukas Wunner wrote:
quoted hunk ↗ jump to hunk
@@ -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.