We need a way to customize the behaviour of the EFI boot stub, in
particular, we need a way to disable the "chunking" workaround, used
when reading files from the EFI System Partition.

One of my machines doesn't cope well when reading files in 1MB chunks to
a buffer above the 4GB mark - it appears that the "chunking" bug
workaround triggers another firmware bug. This was only discovered with
commit 4bf7111f ("x86/efi: Support initrd loaded above 4G"), and
that commit is perfectly valid. The symptom I observed was a corrupt
initrd rather than any kind of crash.

efi= is now used to specify EFI parameters in two very different
execution environments, the EFI boot stub and during kernel boot.

There is also a slight performance optimization by enabling efi=nochunk,
but that's offset by the fact that you're more likely to run into
firmware issues, at least on x86. This is the rationale behind leaving
the workaround enabled by default.

Also provide some documentation for EFI_READ_CHUNK_SIZE and why we're
using the current value of 1MB.
Tested-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Borislav Petkov <bp@suse.de>
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>

Instead of truncating UTF-16 assuming all characters is ASCII,
properly convert it to UTF-8.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
[ Bug and style fixes. ]
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add the get_dram_base() function, shared by arm/arm64.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add a wrapper for printk to standardize the prefix for informational and
error messages from the EFI stub.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

An #ifdef CONFIG_ARM clause in efi-stub-helper.c got included with some
of the generic stub rework by Roy Franz. Drop it here to make subsequent
patches less confusing.

Also, In handle_cmdline_files(), fh is not initialized, and while the
overall logic around this handling appears safe, gcc does not always
pick this up. Initialize to NULL to remove the resulting warning.
Signed-off-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

We're currently passing the file handle for the root file system to
efi_file_read() and efi_file_close(), instead of the file handle for the
file we wish to read/close.

While this has worked up until now, it seems that it has only been by
pure luck. Olivier explains,

 "The issue is the UEFI Fat driver might return the same function for
  'fh->read()' and 'h->read()'. While in our case it does not work with
  a different implementation of EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. In our
  case, we return a different pointer when reading a directory and
  reading a file."

Fixing this actually clears up the two functions because we can drop one
of the arguments, and instead only pass a file 'handle' argument.
Reported-by: NOlivier Martin <olivier.martin@arm.com>
Reviewed-by: NOlivier Martin <olivier.martin@arm.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The ARM EFI boot stub doesn't need to care about the efi_early
infrastructure that x86 requires in order to do mixed mode thunking. So
wrap everything up in an efi_call_early() macro.

This allows x86 to do the necessary indirection jumps to call whatever
firmware interface is necessary (native or mixed mode), but also allows
the ARM folks to mask the fact that they don't support relocation in the
boot stub and need to pass 'sys_table_arg' to every function.

[ hpa: there are no object code changes from this patch ]
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20140326091011.GB2958@console-pimps.org
Cc: Roy Franz <roy.franz@linaro.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

It's not possible to dereference the EFI System table directly when
booting a 64-bit kernel on a 32-bit EFI firmware because the size of
pointers don't match.

In preparation for supporting the above use case, build a list of
function pointers on boot so that callers don't have to worry about
converting pointer sizes through multiple levels of indirection.
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Remove a redundant memset() call from efi_relocate_kernel() that
was clearing memory that would be used by BSS in non-compressed
images loaded with this function.  This clear was redundant with
the clearing done in the image itself, and also implemented incorrectly
with a 0 length.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

warnings from gcc:
warning: label 'free_pool' defined but not used [-Wunused-label]
warning: value computed is not used [-Wunused-value]
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

EFI calls can made directly on ARM, so the function pointers
are directly invoked.  This allows types to be checked at
compile time, so here we ensure that the parameters match
the function signature. The wrappers used by x86 prevent
any type checking.
Correct the type of chunksize to be based on native
width as specified by the EFI_FILE_PROTOCOL read()
function.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename variables to be not initrd specific, as now the function
loads arbitrary files.  This change is exclusively renames
and comment changes to reflect the generalization.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The handle_cmdline_files now takes the option to handle as a string,
and returns the loaded data through parameters, rather than taking
an x86 specific setup_header structure.  For ARM, this will be used
to load a device tree blob in addition to initrd images.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Make efi_free() safely callable with size of 0, similar to free() being
callable with NULL pointers, and do nothing in that case.
Remove size checks that this makes redundant.  This also avoids some
size checks in the ARM EFI stub code that will be added as well.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add arguments for returning the descriptor version and also
the memory map key.  The key is required for calling
exit_boot_services().
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename function in preparation for making it more flexible
and sharing it.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Move the open-coded conversion to a shared function for
use by all architectures.  Change the allocation to prefer
a high address for ARM, as this is required to avoid conflicts
with reserved regions in low memory.  We don't know the specifics
of these regions until after we process the command line and
device tree.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename relocate_kernel() to efi_relocate_kernel(), and take
parameters rather than x86 specific structure.  Add max_addr
argument as for ARM we have some address constraints that we
need to enforce when relocating the kernel.  Add alloc_size
parameter for use by ARM64 which uses an uncompressed kernel,
and needs to allocate space for BSS.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The relocate_kernel() function will be generalized and used
by all architectures, as they all have similar requirements.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The efi_high_alloc() and efi_low_alloc() functions
use the EFI_ALLOCATE_ADDRESS option to the EFI
function allocate_pages(), which requires a minimum
of page alignment, and rejects all other requests.
The existing code could fail to allocate depending
on allocation size, as although repeated allocation
attempts were made, none were guaranteed to be page
aligned.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Rename them to be more similar, as low_free() could be used to free
memory allocated by both high_alloc() and low_alloc().
high_alloc() -> efi_high_alloc()
low_alloc()  -> efi_low_alloc()
low_free()   -> efi_free()
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

Add system table pointer argument to shared EFI stub related functions
so they no longer use a global system table pointer as they did when part
of eboot.c.  For the ARM EFI stub this allows us to avoid global
variables completely and thereby not have to deal with GOT fixups.
Not having the EFI stub fixup its GOT, which is shared with the
decompressor, simplifies the relocating of the zImage to a
bootable address.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

No code changes made, just moving functions and #define from x86 arch
directory to common location.  Code is shared using #include, similar
to how decompression code is shared among architectures.
Signed-off-by: NRoy Franz <roy.franz@linaro.org>
Acked-by: NMark Salter <msalter@redhat.com>
Reviewed-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>