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Diffstat (limited to 'Documentation/i386/boot.txt')
| -rw-r--r-- | Documentation/i386/boot.txt | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt index fc49b79bc1a..0fac3465f2e 100644 --- a/Documentation/i386/boot.txt +++ b/Documentation/i386/boot.txt @@ -42,6 +42,8 @@ Protocol 2.05: (Kernel 2.6.20) Make protected mode kernel relocatable. Protocol 2.06: (Kernel 2.6.22) Added a field that contains the size of the boot command line +Protocol 2.09: (kernel 2.6.26) Added a field of 64-bit physical + pointer to single linked list of struct setup_data. **** MEMORY LAYOUT @@ -170,6 +172,10 @@ 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+ payload_offset Offset of kernel payload +024C/4 2.08+ payload_length Length of kernel payload +0250/8 2.09+ setup_data 64-bit physical pointer to linked list + of struct setup_data (1) For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -512,6 +518,32 @@ Protocol: 2.07+ A pointer to data that is specific to hardware subarch +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 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: payload_length +Type: read +Offset/size: 0x24c/4 +Protocol: 2.08+ + + The length of the payload. + +**** THE IMAGE CHECKSUM + +From boot protocol version 2.08 onwards the CRC-32 is calculated over +the entire file using the characteristic polynomial 0x04C11DB7 and an +initial remainder of 0xffffffff. The checksum is appended to the +file; therefore the CRC of the file up to the limit specified in the +syssize field of the header is always 0. **** THE KERNEL COMMAND LINE @@ -544,6 +576,28 @@ command line is entered using the following protocol: covered by setup_move_size, so you may need to adjust this field. +Field name: setup_data +Type: write (obligatory) +Offset/size: 0x250/8 +Protocol: 2.09+ + + The 64-bit physical pointer to NULL terminated single linked list of + struct setup_data. This is used to define a more extensible boot + parameters passing mechanism. The definition of struct setup_data is + as follow: + + struct setup_data { + u64 next; + u32 type; + u32 len; + u8 data[0]; + }; + + Where, the next is a 64-bit physical pointer to the next node of + linked list, the next field of the last node is 0; the type is used + to identify the contents of data; the len is the length of data + field; the data holds the real payload. + **** MEMORY LAYOUT OF THE REAL-MODE CODE |