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From: Jian J Wang <jian.j.wang@intel.com>
To: edk2-devel@lists.01.org
Subject: [PATCH 0/3] Remove dependency on PcdNullPointerDetectionPropertyMask
Date: Wed,  6 Dec 2017 15:31:17 +0800	[thread overview]
Message-ID: <20171206073120.2248-1-jian.j.wang@intel.com> (raw)

Due to the introduction of NULL pointer detection feature, page 0 will be
disabled if the feature is enabled, which will cause legacy code failed to
update legacy data in page 0.

To avoid page fault caused by above feature in legacy code, legacy related
drivers have to enable page 0 temporarily before accessing page 0 and disable
it afterwards.

Old GCD servie has a bug which paging related attributes are not awared and
managed by GCD service. The legacy code has to use PCD
PcdNullPointerDetectionPropertyMask to know if page 0 is disabled or not.
As a result, two methods

    EnableNullDetection()
    DisableNullDetection()

were introduced to do enable/disable job just mentioned.

But the newly added PcdNullPointerDetectionPropertyMask caused backward
compatibility issue in some packages having legcy drivers. Since the
attributes missing issue in GCD services has been fixed, it's now able to
eliminate the dependency on this PCD.

Jian J Wang (3):
  IntelFrameworkPkg/LegacyBios.h: Add a macro to guarantee page 0 access
  IntelFrameworkModulePkg/LegacyBiosDxe: Use macro to enable/disable
    page 0
  IntelFrameworkModulePkg/KeyboardDxe: Use macro to enable/disable page
    0

 .../Csm/BiosThunk/KeyboardDxe/BiosKeyboard.c       | 118 ++----------------
 .../Csm/BiosThunk/KeyboardDxe/KeyboardDxe.inf      |   1 -
 .../Csm/LegacyBiosDxe/LegacyBda.c                  |  53 ++++----
 .../Csm/LegacyBiosDxe/LegacyBios.c                 | 135 ++-------------------
 .../Csm/LegacyBiosDxe/LegacyBiosDxe.inf            |   1 -
 .../Csm/LegacyBiosDxe/LegacyBiosInterface.h        |  16 ---
 .../Csm/LegacyBiosDxe/LegacyBootSupport.c          |  80 ++++++------
 .../Csm/LegacyBiosDxe/LegacyPci.c                  |  72 ++++++-----
 IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c  |  51 ++++----
 IntelFrameworkPkg/Include/Protocol/LegacyBios.h    |  34 ++++++
 10 files changed, 179 insertions(+), 382 deletions(-)

-- 
2.15.1.windows.2



             reply	other threads:[~2017-12-06  7:27 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-06  7:31 Jian J Wang [this message]
2017-12-06  7:31 ` [PATCH 1/3] IntelFrameworkPkg/LegacyBios.h: Add a macro to guarantee page 0 access Jian J Wang
2017-12-06  9:31   ` Ni, Ruiyu
2017-12-06 12:36     ` Wang, Jian J
2017-12-06  7:31 ` [PATCH 2/3] IntelFrameworkModulePkg/LegacyBiosDxe: Use macro to enable/disable page 0 Jian J Wang
2017-12-06  9:32   ` Ni, Ruiyu
2017-12-06 12:38     ` Wang, Jian J
2017-12-06  7:31 ` [PATCH 3/3] IntelFrameworkModulePkg/KeyboardDxe: " Jian J Wang

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