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[efi] Install our own disk I/O protocol and claim exclusive use of it
The EFI FAT filesystem driver has a bug: if a block device contains no FAT filesystem but does have an EFI_SIMPLE_FILE_SYSTEM_PROTOCOL instance, the FAT driver will assume that it must have previously installed the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. This causes the FAT driver to claim control of our device, and to refuse to stop driving it, which prevents us from later uninstalling correctly. Work around this bug by opening the disk I/O protocol ourselves, thereby preventing the FAT driver from opening it. Note that the alternative approach of opening the block I/O protocol (and thereby in theory preventing DiskIo from attaching to the block I/O protocol) causes an endless loop of calls to our DRIVER_STOP method when starting the EFI shell. I have no idea why this is. Signed-off-by: Michael Brown <mcb30@ipxe.org>
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/** @file | ||
Disk IO protocol as defined in the UEFI 2.0 specification. | ||
The Disk IO protocol is used to convert block oriented devices into byte | ||
oriented devices. The Disk IO protocol is intended to layer on top of the | ||
Block IO protocol. | ||
Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR> | ||
This program and the accompanying materials | ||
are licensed and made available under the terms and conditions of the BSD License | ||
which accompanies this distribution. The full text of the license may be found at | ||
http://opensource.org/licenses/bsd-license.php | ||
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, | ||
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. | ||
**/ | ||
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#ifndef __DISK_IO_H__ | ||
#define __DISK_IO_H__ | ||
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FILE_LICENCE ( BSD3 ); | ||
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#define EFI_DISK_IO_PROTOCOL_GUID \ | ||
{ \ | ||
0xce345171, 0xba0b, 0x11d2, {0x8e, 0x4f, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b } \ | ||
} | ||
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/// | ||
/// Protocol GUID name defined in EFI1.1. | ||
/// | ||
#define DISK_IO_PROTOCOL EFI_DISK_IO_PROTOCOL_GUID | ||
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typedef struct _EFI_DISK_IO_PROTOCOL EFI_DISK_IO_PROTOCOL; | ||
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/// | ||
/// Protocol defined in EFI1.1. | ||
/// | ||
typedef EFI_DISK_IO_PROTOCOL EFI_DISK_IO; | ||
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/** | ||
Read BufferSize bytes from Offset into Buffer. | ||
@param This Protocol instance pointer. | ||
@param MediaId Id of the media, changes every time the media is replaced. | ||
@param Offset The starting byte offset to read from | ||
@param BufferSize Size of Buffer | ||
@param Buffer Buffer containing read data | ||
@retval EFI_SUCCESS The data was read correctly from the device. | ||
@retval EFI_DEVICE_ERROR The device reported an error while performing the read. | ||
@retval EFI_NO_MEDIA There is no media in the device. | ||
@retval EFI_MEDIA_CHNAGED The MediaId does not matched the current device. | ||
@retval EFI_INVALID_PARAMETER The read request contains device addresses that are not | ||
valid for the device. | ||
**/ | ||
typedef | ||
EFI_STATUS | ||
(EFIAPI *EFI_DISK_READ)( | ||
IN EFI_DISK_IO_PROTOCOL *This, | ||
IN UINT32 MediaId, | ||
IN UINT64 Offset, | ||
IN UINTN BufferSize, | ||
OUT VOID *Buffer | ||
); | ||
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/** | ||
Writes a specified number of bytes to a device. | ||
@param This Indicates a pointer to the calling context. | ||
@param MediaId ID of the medium to be written. | ||
@param Offset The starting byte offset on the logical block I/O device to write. | ||
@param BufferSize The size in bytes of Buffer. The number of bytes to write to the device. | ||
@param Buffer A pointer to the buffer containing the data to be written. | ||
@retval EFI_SUCCESS The data was written correctly to the device. | ||
@retval EFI_WRITE_PROTECTED The device can not be written to. | ||
@retval EFI_DEVICE_ERROR The device reported an error while performing the write. | ||
@retval EFI_NO_MEDIA There is no media in the device. | ||
@retval EFI_MEDIA_CHNAGED The MediaId does not matched the current device. | ||
@retval EFI_INVALID_PARAMETER The write request contains device addresses that are not | ||
valid for the device. | ||
**/ | ||
typedef | ||
EFI_STATUS | ||
(EFIAPI *EFI_DISK_WRITE)( | ||
IN EFI_DISK_IO_PROTOCOL *This, | ||
IN UINT32 MediaId, | ||
IN UINT64 Offset, | ||
IN UINTN BufferSize, | ||
IN VOID *Buffer | ||
); | ||
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#define EFI_DISK_IO_PROTOCOL_REVISION 0x00010000 | ||
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/// | ||
/// Revision defined in EFI1.1 | ||
/// | ||
#define EFI_DISK_IO_INTERFACE_REVISION EFI_DISK_IO_PROTOCOL_REVISION | ||
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/// | ||
/// This protocol is used to abstract Block I/O interfaces. | ||
/// | ||
struct _EFI_DISK_IO_PROTOCOL { | ||
/// | ||
/// The revision to which the disk I/O interface adheres. All future | ||
/// revisions must be backwards compatible. If a future version is not | ||
/// backwards compatible, it is not the same GUID. | ||
/// | ||
UINT64 Revision; | ||
EFI_DISK_READ ReadDisk; | ||
EFI_DISK_WRITE WriteDisk; | ||
}; | ||
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extern EFI_GUID gEfiDiskIoProtocolGuid; | ||
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#endif |
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