2ce7e221e7
The current implementation of QemuFwCfgLib is: - stateful - implicitly initialized in the library constructor. OVMF's SEC runs from read-only memory/flash. When the library is linked into a SEC binary (which currently never happens), the "mQemuFwCfgSupported" global variable becomes read-only, making the library non-functional. Extract the stateful, implicitly initialized library implementation into a separate file, making room for a stateless, explicitly queried implementation that's usable in SEC. Restrict the stateful implementation to the current, non-SEC clients. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15045 6f19259b-4bc3-4df7-8a09-765794883524
93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
/** @file
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Stateful and implicitly initialized fw_cfg library implementation.
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Copyright (C) 2013, Red Hat, Inc.
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Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials are licensed and made available
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under the terms and conditions of the BSD License which accompanies this
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distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
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WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Library/DebugLib.h>
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#include <Library/QemuFwCfgLib.h>
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STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
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/**
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Returns a boolean indicating if the firmware configuration interface
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is available or not.
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This function may change fw_cfg state.
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@retval TRUE The interface is available
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@retval FALSE The interface is not available
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**/
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BOOLEAN
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EFIAPI
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QemuFwCfgIsAvailable (
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VOID
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)
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{
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return InternalQemuFwCfgIsAvailable ();
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}
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RETURN_STATUS
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EFIAPI
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QemuFwCfgInitialize (
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VOID
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)
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{
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UINT32 Signature;
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UINT32 Revision;
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//
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// Enable the access routines while probing to see if it is supported.
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//
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mQemuFwCfgSupported = TRUE;
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QemuFwCfgSelectItem (QemuFwCfgItemSignature);
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Signature = QemuFwCfgRead32 ();
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DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));
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QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
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Revision = QemuFwCfgRead32 ();
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DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));
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if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||
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(Revision < 1)
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) {
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DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));
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mQemuFwCfgSupported = FALSE;
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return RETURN_SUCCESS;
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}
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DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));
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return RETURN_SUCCESS;
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}
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/**
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Returns a boolean indicating if the firmware configuration interface is
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available for library-internal purposes.
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This function never changes fw_cfg state.
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@retval TRUE The interface is available internally.
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@retval FALSE The interface is not available internally.
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**/
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BOOLEAN
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EFIAPI
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InternalQemuFwCfgIsAvailable (
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VOID
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)
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{
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return mQemuFwCfgSupported;
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}
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