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7e1550b8f2
The current implementation of efi_mem_desc_lookup() includes the following check on the memory descriptor it returns: if (!(md->attribute & EFI_MEMORY_RUNTIME) && md->type != EFI_BOOT_SERVICES_DATA && md->type != EFI_RUNTIME_SERVICES_DATA) { continue; } This means that only EfiBootServicesData or EfiRuntimeServicesData regions are considered, or any other region type provided that it has the EFI_MEMORY_RUNTIME attribute set. Given what the name of the function implies, and the fact that any physical address can be described in the UEFI memory map only a single time, it does not make sense to impose this condition in the body of the loop, but instead, should be imposed by the caller depending on the value that is returned to it. Two such callers exist at the moment: - The BGRT code when running on x86, via efi_mem_reserve() and efi_arch_mem_reserve(). In this case, the region is already known to be EfiBootServicesData, and so the check is redundant. - The ESRT handling code which introduced this function, which calls it both directly from efi_esrt_init() and again via efi_mem_reserve() and efi_arch_mem_reserve() [on x86]. So let's move this check into the callers instead. This preserves the current behavior both for BGRT and ESRT handling, and allows the lookup routine to be reused by other [upcoming] users that don't have this limitation. In the ESRT case, keep the entire condition, so that platforms that deviate from the UEFI spec and use something other than EfiBootServicesData for the ESRT table will keep working as before. For x86's efi_arch_mem_reserve() implementation, limit the type to EfiBootServicesData, since it is the only type the reservation code expects to operate on in the first place. While we're at it, drop the __init annotation so that drivers can use it as well. Tested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180711094040.12506-8-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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