efi_get_memory_map() allocates a buffer to store the memory map that it
retrieves.  This buffer may need to be reused by the client after
ExitBootServices() is called, at which point allocations are not longer
permitted.  To support this usecase, provide the allocated buffer size back
to the client, and allocate some additional headroom to account for any
reasonable growth in the map that is likely to happen between the call to
efi_get_memory_map() and the client reusing the buffer.
Signed-off-by: NJeffrey Hugo <jhugo@codeaurora.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>

There are two problems with the UEFI stub DT memory node removal
routine:
- it deletes nodes as it traverses the tree, which happens to work
  but is not supported, as deletion invalidates the node iterator;
- deleting memory nodes entirely may discard annotations in the form
  of additional properties on the nodes.

Since the discovery of DT memory nodes occurs strictly before the
UEFI init sequence, we can simply clear the memblock memory table
before parsing the UEFI memory map. This way, it is no longer
necessary to remove the nodes, so we can remove that logic from the
stub as well.
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Acked-by: NSteve Capper <steve.capper@arm.com>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Since arm64 does not use a decompressor that supplies an execution
environment where it is feasible to some extent to provide a source of
randomness, the arm64 KASLR kernel depends on the bootloader to supply
some random bits in the /chosen/kaslr-seed DT property upon kernel entry.

On UEFI systems, we can use the EFI_RNG_PROTOCOL, if supplied, to obtain
some random bits. At the same time, use it to randomize the offset of the
kernel Image in physical memory.
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch fix multiple spelling typos found in
various part of kernel.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

With the stub to kernel interface being promoted to a proper interface
so that other agents than the stub can boot the kernel proper in EFI
mode, we can remove the linux,uefi-stub-kern-ver field, considering
that its original purpose was to prevent this from happening in the
first place.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: NMatt Fleming <matt.fleming@intel.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

When allocating memory for the copy of the FDT that the stub
modifies and passes to the kernel, it uses the current size as
an estimate of how much memory to allocate, and increases it page
by page if it turns out to be too small. However, when loading
the FDT from a UEFI configuration table, the estimated size is
left at its default value of zero, and the allocation loop runs
starting from zero all the way up to the allocation size that
finally fits the updated FDT.

Instead, retrieve the size of the FDT from the FDT header when
loading it from the UEFI config table.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

In order to support kexec, the kernel needs to be able to deal with the
state of the UEFI firmware after SetVirtualAddressMap() has been called.
To avoid having separate code paths for non-kexec and kexec, let's move
the call to SetVirtualAddressMap() to the stub: this will guarantee us
that it will only be called once (since the stub is not executed during
kexec), and ensures that the UEFI state is identical between kexec and
normal boot.

This implies that the layout of the virtual mapping needs to be created
by the stub as well. All regions are rounded up to a naturally aligned
multiple of 64 KB (for compatibility with 64k pages kernels) and recorded
in the UEFI memory map. The kernel proper reads those values and installs
the mappings in a dedicated set of page tables that are swapped in during
UEFI Runtime Services calls.
Acked-by: NLeif Lindholm <leif.lindholm@linaro.org>
Acked-by: NMatt Fleming <matt.fleming@intel.com>
Tested-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>

Commit 86c8b27a:
 "arm64: ignore DT memreserve entries when booting in UEFI mode

prevents early_init_fdt_scan_reserved_mem() from being called for
arm64 kernels booting via UEFI. This was done because the kernel
will use the UEFI memory map to determine reserved memory regions.
That approach has problems in that early_init_fdt_scan_reserved_mem()
also reserves the FDT itself and any node-specific reserved memory.
By chance of some kernel configs, the FDT may be overwritten before
it can be unflattened and the kernel will fail to boot. More subtle
problems will result if the FDT has node specific reserved memory
which is not really reserved.

This patch has the UEFI stub remove the memory reserve map entries
from the FDT as it does with the memory nodes. This allows
early_init_fdt_scan_reserved_mem() to be called unconditionally
so that the other needed reservations are made.
Signed-off-by: NMark Salter <msalter@redhat.com>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

This patch changes both x86 and arm64 efistub implementations
from #including shared .c files under drivers/firmware/efi to
building shared code as a static library.

The x86 code uses a stub built into the boot executable which
uncompresses the kernel at boot time. In this case, the library is
linked into the decompressor.

In the arm64 case, the stub is part of the kernel proper so the library
is linked into the kernel proper as well.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

In order to move from the #include "../../../xxxxx.c" anti-pattern used
by both the x86 and arm64 versions of the stub to a static library
linked into either the kernel proper (arm64) or a separate boot
executable (x86), there is some prepatory work required.

This patch does the following:
- move forward declarations of functions shared between the arch
  specific and the generic parts of the stub to include/linux/efi.h
- move forward declarations of functions shared between various .c files
  of the generic stub code to a new local header file called "efistub.h"
- add #includes to all .c files which were formerly relying on the
  #includor to include the correct header files
- remove all static modifiers from functions which will need to be
  externally visible once we move to a static library
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The shared efistub code for ARM and arm64 contains a local copy of
linux_banner, allowing it to be referenced from separate executables
such as the ARM decompressor. However, this introduces a dependency on
generated header files, causing unnecessary rebuilds of the stub itself
and, in case of arm64, vmlinux which contains it.

On arm64, the copy is not actually needed since we can reference the
original symbol directly, and as it turns out, there may be better ways
to deal with this for ARM as well, so let's remove it from the shared
code. If it still needs to be reintroduced for ARM later, it should live
under arch/arm anyway and not in shared code.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The shared efistub code for ARM and arm64 contains a local copy of
linux_banner, allowing it to be referenced from separate executables
such as the ARM decompressor. However, this introduces a dependency on
generated header files, causing unnecessary rebuilds of the stub itself
and, in case of arm64, vmlinux which contains it.

On arm64, the copy is not actually needed since we can reference the
original symbol directly, and as it turns out, there may be better ways
to deal with this for ARM as well, so let's remove it from the shared
code. If it still needs to be reintroduced for ARM later, it should live
under arch/arm anyway and not in shared code.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

This patch fixes a few compiler warning in the efi code for unused
variable, discarding const qualifier and wrong pointer type:

drivers/firmware/efi/fdt.c|66 col 22| warning: unused variable ‘name’ [-Wunused-variable]
drivers/firmware/efi/efi.c|368 col 3| warning: passing argument 3 of ‘of_get_flat_dt_prop’ from incompatible pointer type [enabled by default]
drivers/firmware/efi/efi.c|368 col 8| warning: assignment discards ‘const’ qualifier from pointer target type [enabled by default]
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Both ARM and ARM64 stubs will update the device tree that they pass to
the kernel.  In both cases they primarily need to add the same UEFI
related information, so the function can be shared.  Create a new FDT
related file for this to avoid use of architecture #ifdefs in
efi-stub-helper.c.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
[ Fixed memory node deletion code. ]
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Acked-by: NGrant Likely <grant.likely@linaro.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>