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authorRusty Russell <rusty@rustcorp.com.au>2007-10-21 19:41:33 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-22 11:13:17 -0400
commite5371ac566b6794f2125393b6850909de9e16f58 (patch)
treeac08bad552ebfb1f0deb55f88230369f236b8ac0 /Documentation
parent55b70a0300b873c0ec7ea6e33752af56f41250ce (diff)
update boot spec to 2.07
Updates for version 2.07 of the boot protocol. This includes: load_flags.KEEP_SEGMENTS- flag to request/inhibit segment reloads hardware_subarch - what subarchitecture we're booting under hardware_subarch_data - per-architecture data The intention of these changes is to make booting a paravirtualized kernel work via the normal Linux boot protocol. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/i386/boot.txt34
1 files changed, 33 insertions, 1 deletions
diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt
index 35985b34d5a6..2f75e750e4f5 100644
--- a/Documentation/i386/boot.txt
+++ b/Documentation/i386/boot.txt
@@ -168,6 +168,8 @@ Offset Proto Name Meaning
1680234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not 1680234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not
1690235/3 N/A pad2 Unused 1690235/3 N/A pad2 Unused
1700238/4 2.06+ cmdline_size Maximum size of the kernel command line 1700238/4 2.06+ cmdline_size Maximum size of the kernel command line
171023C/4 2.07+ hardware_subarch Hardware subarchitecture
1720240/8 2.07+ hardware_subarch_data Subarchitecture-specific data
171 173
172(1) For backwards compatibility, if the setup_sects field contains 0, the 174(1) For backwards compatibility, if the setup_sects field contains 0, the
173 real value is 4. 175 real value is 4.
@@ -204,7 +206,7 @@ boot loaders can ignore those fields.
204 206
205The byte order of all fields is littleendian (this is x86, after all.) 207The byte order of all fields is littleendian (this is x86, after all.)
206 208
207Field name: setup_secs 209Field name: setup_sects
208Type: read 210Type: read
209Offset/size: 0x1f1/1 211Offset/size: 0x1f1/1
210Protocol: ALL 212Protocol: ALL
@@ -356,6 +358,13 @@ Protocol: 2.00+
356 - If 0, the protected-mode code is loaded at 0x10000. 358 - If 0, the protected-mode code is loaded at 0x10000.
357 - If 1, the protected-mode code is loaded at 0x100000. 359 - If 1, the protected-mode code is loaded at 0x100000.
358 360
361 Bit 6 (write): KEEP_SEGMENTS
362 Protocol: 2.07+
363 - if 0, reload the segment registers in the 32bit entry point.
364 - if 1, do not reload the segment registers in the 32bit entry point.
365 Assume that %cs %ds %ss %es are all set to flat segments with
366 a base of 0 (or the equivalent for their environment).
367
359 Bit 7 (write): CAN_USE_HEAP 368 Bit 7 (write): CAN_USE_HEAP
360 Set this bit to 1 to indicate that the value entered in the 369 Set this bit to 1 to indicate that the value entered in the
361 heap_end_ptr is valid. If this field is clear, some setup code 370 heap_end_ptr is valid. If this field is clear, some setup code
@@ -480,6 +489,29 @@ Protocol: 2.06+
480 cmdline_size characters. With protocol version 2.05 and earlier, the 489 cmdline_size characters. With protocol version 2.05 and earlier, the
481 maximum size was 255. 490 maximum size was 255.
482 491
492Field name: hardware_subarch
493Type: write
494Offset/size: 0x23c/4
495Protocol: 2.07+
496
497 In a paravirtualized environment the hardware low level architectural
498 pieces such as interrupt handling, page table handling, and
499 accessing process control registers needs to be done differently.
500
501 This field allows the bootloader to inform the kernel we are in one
502 one of those environments.
503
504 0x00000000 The default x86/PC environment
505 0x00000001 lguest
506 0x00000002 Xen
507
508Field name: hardware_subarch_data
509Type: write
510Offset/size: 0x240/8
511Protocol: 2.07+
512
513 A pointer to data that is specific to hardware subarch
514
483 515
484**** THE KERNEL COMMAND LINE 516**** THE KERNEL COMMAND LINE
485 517