From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Thu, 8 Jan 2015 17:51:47 +0000 (+0000)
Subject: efi/libstub: Call get_memory_map() to obtain map and desc sizes
X-Git-Tag: omap-for-v4.1/prcm-dts-mfd-syscon-fix~158^2^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d1a8d66b9177105e898e73716f97eb61842c457a;p=pandora-kernel.git

efi/libstub: Call get_memory_map() to obtain map and desc sizes

This fixes two minor issues in the implementation of get_memory_map():
- Currently, it assumes that sizeof(efi_memory_desc_t) == desc_size,
  which is usually true, but not mandated by the spec. (This was added
  intentionally to allow future additions to the definition of
  efi_memory_desc_t). The way the loop is implemented currently, the
  added slack space may be insufficient if desc_size is larger, which in
  some corner cases could result in the loop never terminating.
- It allocates 32 efi_memory_desc_t entries first (again, using the size
  of the struct instead of desc_size), and frees and reallocates if it
  turns out to be insufficient. Few implementations of UEFI have such small
  memory maps, which results in a unnecessary allocate/free pair on each
  invocation.

Fix this by calling the get_memory_map() boot service first with a '0'
input value for map size to retrieve the map size and desc size from the
firmware and only then perform the allocation, using desc_size rather
than sizeof(efi_memory_desc_t).

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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