linux.git/arch/arm64/kernel/efi.c, branch v4.12

arm64: mm: replace 'block_mappings_allowed' with 'page_mappings_only'

2016-11-07T18:15:04+00:00

In preparation of adding support for contiguous PTE and PMD mappings,
let's replace 'block_mappings_allowed' with 'page_mappings_only', which
will be a more accurate description of the nature of the setting once we
add such contiguous mappings into the mix.

Reviewed-by: Mark Rutland 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Catalin Marinas

arm64: efi: avoid block mappings for unaligned UEFI memory regions

2016-07-01T10:56:26+00:00

When running the OS with a page size > 4 KB, we need to round up mappings
for regions that are not aligned to the OS's page size. We already avoid
block mappings for EfiRuntimeServicesCode/Data regions for other reasons,
but in the unlikely event that other unaliged regions exists that have the
EFI_MEMORY_RUNTIME attribute set, ensure that unaligned regions are always
mapped down to pages. This way, the overlapping page is guaranteed not to
be covered by a block mapping that needs to be split.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Catalin Marinas

arm64: efi: always map runtime services code and data regions down to pages

2016-07-01T10:56:26+00:00

To avoid triggering diagnostics in the MMU code that are finicky about
splitting block mappings into more granular mappings, ensure that regions
that are likely to appear in the Memory Attributes table as well as the
UEFI memory map are always mapped down to pages. This way, we can use
apply_to_page_range() instead of create_pgd_mapping() for the second pass,
which cannot split or merge block entries, and operates strictly on PTEs.

Note that this aligns the arm64 Memory Attributes table handling code with
the ARM code, which already uses apply_to_page_range() to set the strict
permissions.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Catalin Marinas

arm64: mm: add param to force create_pgd_mapping() to use page mappings

2016-07-01T10:56:26+00:00

Add a bool parameter 'allow_block_mappings' to create_pgd_mapping() and
the various helper functions that it descends into, to give the caller
control over whether block entries may be used to create the mapping.

The UEFI runtime mapping routines will use this to avoid creating block
entries that would need to split up into page entries when applying the
permissions listed in the Memory Attributes firmware table.

This also replaces the block_mappings_allowed() helper function that was
added for DEBUG_PAGEALLOC functionality, but the resulting code is
functionally equivalent (given that debug_page_alloc does not operate on
EFI page table entries anyway)

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Catalin Marinas

arm64/efi/libstub: Make screen_info accessible to the UEFI stub

2016-04-28T09:33:59+00:00

Unlike on 32-bit ARM, where we need to pass the stub's version of struct
screen_info to the kernel proper via a configuration table, on 64-bit ARM
it simply involves making the core kernel's copy of struct screen_info
visible to the stub by exposing an __efistub_ alias for it.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Matt Fleming 
Acked-by: Will Deacon 
Cc: Borislav Petkov 
Cc: David Herrmann 
Cc: Mark Rutland 
Cc: Peter Jones 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-21-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar

arm64/efi: Apply strict permissions to UEFI Runtime Services regions

2016-04-28T09:33:53+00:00

Recent UEFI versions expose permission attributes for runtime services
memory regions, either in the UEFI memory map or in the separate memory
attributes table. This allows the kernel to map these regions with
stricter permissions, rather than the RWX permissions that are used by
default. So wire this up in our mapping routine.

Note that in the absence of permission attributes, we still only map
regions of type EFI_RUNTIME_SERVICE_CODE with the executable bit set.
Also, we base the mapping attributes of EFI_MEMORY_MAPPED_IO on the
type directly rather than on the absence of the EFI_MEMORY_WB attribute.
This is more correct, but is also required for compatibility with the
upcoming support for the Memory Attributes Table, which only carries
permission attributes, not memory type attributes.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Matt Fleming 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Leif Lindholm 
Cc: Mark Rutland 
Cc: Peter Jones 
Cc: Peter Zijlstra 
Cc: Sai Praneeth Prakhya 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-12-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar

arm64/efi: refactor EFI init and runtime code for reuse by 32-bit ARM

2015-12-09T16:57:23+00:00

This refactors the EFI init and runtime code that will be shared
between arm64 and ARM so that it can be built for both archs.

Reviewed-by: Matt Fleming 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Will Deacon

arm64/efi: split off EFI init and runtime code for reuse by 32-bit ARM

2015-12-09T16:57:23+00:00

This splits off the early EFI init and runtime code that
- discovers the EFI params and the memory map from the FDT, and installs
  the memblocks and config tables.
- prepares and installs the EFI page tables so that UEFI Runtime Services
  can be invoked at the virtual address installed by the stub.

This will allow it to be reused for 32-bit ARM.

Reviewed-by: Matt Fleming 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Will Deacon

arm64/efi: mark UEFI reserved regions as MEMBLOCK_NOMAP

2015-12-09T16:57:23+00:00

Change the EFI memory reservation logic to use memblock_mark_nomap()
rather than memblock_reserve() to mark UEFI reserved regions as
occupied. In addition to reserving them against allocations done by
memblock, this will also prevent them from being covered by the linear
mapping.

Reviewed-by: Matt Fleming 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Will Deacon

arm64: efi: fix initcall return values

2015-11-26T18:15:54+00:00

Even though initcall return values are typically ignored, the
prototype is to return 0 on success or a negative errno value on
error. So fix the arm_enable_runtime_services() implementation to
return 0 on conditions that are not in fact errors, and return a
meaningful error code otherwise.

Signed-off-by: Ard Biesheuvel 
Reviewed-by: Matt Fleming 
Acked-by: Will Deacon 
Signed-off-by: Catalin Marinas