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x86: boot protocol updates
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Also update field names to simply payload_{offset,length} so as to not rule
out uncompressed images.

Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Ian Campbell authored and Ingo Molnar committed Apr 17, 2008
1 parent bc0a733 commit 87253d1
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18 changes: 10 additions & 8 deletions Documentation/i386/boot.txt
Original file line number Diff line number Diff line change
Expand Up @@ -170,8 +170,8 @@ Offset Proto Name Meaning
0238/4 2.06+ cmdline_size Maximum size of the kernel command line
023C/4 2.07+ hardware_subarch Hardware subarchitecture
0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data
0248/4 2.08+ compressed_payload_offset
024C/4 2.08+ compressed_payload_length
0248/4 2.08+ payload_offset Offset of kernel payload
024C/4 2.08+ payload_length Length of kernel payload

(1) For backwards compatibility, if the setup_sects field contains 0, the
real value is 4.
Expand Down Expand Up @@ -514,22 +514,24 @@ Protocol: 2.07+

A pointer to data that is specific to hardware subarch

Field name: compressed_payload_offset
Field name: payload_offset
Type: read
Offset/size: 0x248/4
Protocol: 2.08+

If non-zero then this field contains the offset from the end of the
real-mode code to the compressed payload. The compression format
should be determined using the standard magic number, currently only
gzip is used.
real-mode code to the payload.

The payload may be compressed. The format of both the compressed and
uncompressed data should be determined using the standard magic
numbers. Currently only gzip compressed ELF is used.

Field name: compressed_payload_length
Field name: payload_length
Type: read
Offset/size: 0x24c/4
Protocol: 2.08+

The length of the compressed payload.
The length of the payload.

**** THE IMAGE CHECKSUM

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6 changes: 2 additions & 4 deletions arch/x86/boot/header.S
Original file line number Diff line number Diff line change
Expand Up @@ -224,10 +224,8 @@ hardware_subarch: .long 0 # subarchitecture, added with 2.07

hardware_subarch_data: .quad 0

compressed_payload_offset:
.long input_data
compressed_payload_length:
.long input_data_end-input_data
payload_offset: .long input_data
payload_length: .long input_data_end-input_data

# End of setup header #####################################################

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