u-boot.git/lib/efi_loader/efi_memory.c, branch v2016.11

efi_loader: Do not leak memory when unlinking a mapping

2016-10-18T07:08:08+00:00

As soon as a mapping is unlinked from the list, there are no further
references to it, so it should be freed. If it not unlinked,
update the start address and length.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Keep memory mapping sorted when splitting an entry

2016-10-18T07:08:07+00:00

The code assumes sorted mappings in descending address order. When
splitting a mapping, insert the new part next to the current mapping.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Readd freed pages to memory pool

2016-10-18T07:08:07+00:00

Currently each allocation creates a new mapping. Readding the mapping
as free memory (EFI_CONVENTIONAL_MEMORY) potentially allows to hand out
an existing mapping, thus limiting the number of mapping descriptors in
the memory map.

Mitigates a problem with current (4.8rc7) linux kernels when doing an
efi_get_memory map, resulting in an infinite loop. Space for the memory
map is reserved with allocate_pool (implicitly creating a new mapping) and
filled. If there is insufficient slack space (8 entries) in the map, the
space is freed and a new round is started, with space for one more entry.
As each round increases requirement and allocation by exactly one, there
is never enough slack space. (At least 32 entries are allocated, so as
long as there are less than 24 entries, there is enough slack).
Earlier kernels reserved no slack, and did less allocations, so this
problem was not visible.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Track size of pool allocations to allow freeing

2016-10-18T07:08:07+00:00

We need a functional free_pool implementation, as otherwise each
allocate_pool causes growth of the memory descriptor table.

Different to free_pages, free_pool does not provide the size for the
to be freed allocation, thus we have to track the size ourselves.

As the only EFI requirement for pool allocation is an alignment of
8 bytes, we can keep allocating a range using the page allocator,
reserve the first 8 bytes for our bookkeeping and hand out the
remainder to the caller. This saves us from having to use any
independent data structures for tracking.

To simplify the conversion between pool allocations and the corresponding
page allocation, we create an auxiliary struct efi_pool_allocation.

Given the allocation size free_pool size can handoff freeing the page
range, which was indirectly allocated by a call to allocate_pool,
to free_pages.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Move efi_allocate_pool implementation to efi_memory.c

2016-10-18T07:08:07+00:00

We currently handle efi_allocate_pool() in our boot time service
file. In the following patch, pool allocation will receive additional
internal semantics that we should preserve inside efi_memory.c instead.

As foundation for those changes, split the function into an externally
facing efi_allocate_pool_ext() for use by payloads and an internal helper
efi_allocate_pool() in efi_memory.c that handles the actual allocation.

While at it, change the magic 0xfff / 12 constants to the more obvious
EFI_PAGE_MASK/SHIFT defines.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Fix memory map size check to avoid out-of-bounds access

2016-10-18T07:08:07+00:00

The current efi_get_memory_map() function overwrites the map_size
property before reading its value. That way the sanity check whether our
memory map fits into the given array always succeeds, potentially
overwriting arbitrary payload memory.

This patch moves the property update write after its sanity check, so
that the check actually verifies the correct value.

So far this has not triggered any known bugs, but we're better off safe
than sorry.

If the buffer is to small, the returned memory_map_size indicates the
required size to the caller.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: Update description of internal efi_mem_carve_out

2016-10-18T07:08:06+00:00

In 74c16acce30bb882ad5951829d8dafef8eea564c the return values where
changed, but the description was kept.

Signed-off-by: Stefan Brüns 
Reviewed-by: Alexander Graf 
Signed-off-by: Alexander Graf

efi_loader: provide efi_mem_desc version

2016-09-07T12:49:07+00:00

Provide version of struct efi_mem_desc in efi_get_memory_map().

EFI_BOOT_SERVICES.GetMemoryMap() in UEFI specification v2.6 defines
memory descriptor version to 1. Linux kernel also expects descriptor
version to be 1 and prints following warning during boot if its not:

Unexpected EFI_MEMORY_DESCRIPTOR version 0

Signed-off-by: Mian Yousaf Kaukab

efi_loader: Add debug output for efi_add_memory_map()

2016-07-22T18:46:23+00:00

Tracing the arguments has been helpful for pinpointing overflows.

Cc: Alexander Graf 
Signed-off-by: Andreas Färber 
Reviewed-by: Alexander Graf

efi_loader: Don't allocate from memory holes

2016-06-06T17:39:16+00:00

When a payload calls our memory allocator with the exact address hint, we
happily allocate memory from completely unpopulated regions. Payloads however
expect this to only succeed if they would be allocating from free conventional
memory.

This patch makes the logic behind those checks a bit more obvious and ensures
that we always allocate from known good free conventional memory regions if we
want to allocate ram.

Reported-by: Jonathan Gray 
Signed-off-by: Alexander Graf