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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/i386
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'Documentation/i386')
-rw-r--r--Documentation/i386/IO-APIC.txt117
-rw-r--r--Documentation/i386/boot.txt441
-rw-r--r--Documentation/i386/usb-legacy-support.txt44
-rw-r--r--Documentation/i386/zero-page.txt84
4 files changed, 686 insertions, 0 deletions
diff --git a/Documentation/i386/IO-APIC.txt b/Documentation/i386/IO-APIC.txt
new file mode 100644
index 000000000000..435e69e6e9aa
--- /dev/null
+++ b/Documentation/i386/IO-APIC.txt
@@ -0,0 +1,117 @@
1Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC',
2which is an enhanced interrupt controller, it enables us to route
3hardware interrupts to multiple CPUs, or to CPU groups.
4
5Linux supports all variants of compliant SMP boards, including ones with
6multiple IO-APICs. (multiple IO-APICs are used in high-end servers to
7distribute IRQ load further).
8
9There are (a few) known breakages in certain older boards, which bugs are
10usually worked around by the kernel. If your MP-compliant SMP board does
11not boot Linux, then consult the linux-smp mailing list archives first.
12
13If your box boots fine with enabled IO-APIC IRQs, then your
14/proc/interrupts will look like this one:
15
16 ---------------------------->
17 hell:~> cat /proc/interrupts
18 CPU0
19 0: 1360293 IO-APIC-edge timer
20 1: 4 IO-APIC-edge keyboard
21 2: 0 XT-PIC cascade
22 13: 1 XT-PIC fpu
23 14: 1448 IO-APIC-edge ide0
24 16: 28232 IO-APIC-level Intel EtherExpress Pro 10/100 Ethernet
25 17: 51304 IO-APIC-level eth0
26 NMI: 0
27 ERR: 0
28 hell:~>
29 <----------------------------
30
31some interrupts are still listed as 'XT PIC', but this is not a problem,
32none of those IRQ sources is performance-critical.
33
34
35in the unlikely case that your board does not create a working mp-table,
36you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This
37is nontrivial though and cannot be automated. One sample /etc/lilo.conf
38entry:
39
40 append="pirq=15,11,10"
41
42the actual numbers depend on your system, on your PCI cards and on their
43PCI slot position. Usually PCI slots are 'daisy chained' before they are
44connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4
45lines):
46
47 ,-. ,-. ,-. ,-. ,-.
48 PIRQ4 ----| |-. ,-| |-. ,-| |-. ,-| |--------| |
49 |S| \ / |S| \ / |S| \ / |S| |S|
50 PIRQ3 ----|l|-. `/---|l|-. `/---|l|-. `/---|l|--------|l|
51 |o| \/ |o| \/ |o| \/ |o| |o|
52 PIRQ2 ----|t|-./`----|t|-./`----|t|-./`----|t|--------|t|
53 |1| /\ |2| /\ |3| /\ |4| |5|
54 PIRQ1 ----| |- `----| |- `----| |- `----| |--------| |
55 `-' `-' `-' `-' `-'
56
57every PCI card emits a PCI IRQ, which can be INTA,INTB,INTC,INTD:
58
59 ,-.
60 INTD--| |
61 |S|
62 INTC--|l|
63 |o|
64 INTB--|t|
65 |x|
66 INTA--| |
67 `-'
68
69These INTA-D PCI IRQs are always 'local to the card', their real meaning
70depends on which slot they are in. If you look at the daisy chaining diagram,
71a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ2 of
72the PCI chipset. Most cards issue INTA, this creates optimal distribution
73between the PIRQ lines. (distributing IRQ sources properly is not a
74necessity, PCI IRQs can be shared at will, but it's a good for performance
75to have non shared interrupts). Slot5 should be used for videocards, they
76do not use interrupts normally, thus they are not daisy chained either.
77
78so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in
79Slot2, then you'll have to specify this pirq= line:
80
81 append="pirq=11,9"
82
83the following script tries to figure out such a default pirq= line from
84your PCI configuration:
85
86 echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'
87
88note that this script wont work if you have skipped a few slots or if your
89board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins
90connected in some strange way). E.g. if in the above case you have your SCSI
91card (IRQ11) in Slot3, and have Slot1 empty:
92
93 append="pirq=0,9,11"
94
95[value '0' is a generic 'placeholder', reserved for empty (or non-IRQ emitting)
96slots.]
97
98generally, it's always possible to find out the correct pirq= settings, just
99permute all IRQ numbers properly ... it will take some time though. An
100'incorrect' pirq line will cause the booting process to hang, or a device
101won't function properly (if it's inserted as eg. a module).
102
103If you have 2 PCI buses, then you can use up to 8 pirq values. Although such
104boards tend to have a good configuration.
105
106Be prepared that it might happen that you need some strange pirq line:
107
108 append="pirq=0,0,0,0,0,0,9,11"
109
110use smart try-and-err techniques to find out the correct pirq line ...
111
112good luck and mail to linux-smp@vger.kernel.org or
113linux-kernel@vger.kernel.org if you have any problems that are not covered
114by this document.
115
116-- mingo
117
diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt
new file mode 100644
index 000000000000..1c48f0eba6fb
--- /dev/null
+++ b/Documentation/i386/boot.txt
@@ -0,0 +1,441 @@
1 THE LINUX/I386 BOOT PROTOCOL
2 ----------------------------
3
4 H. Peter Anvin <hpa@zytor.com>
5 Last update 2002-01-01
6
7On the i386 platform, the Linux kernel uses a rather complicated boot
8convention. This has evolved partially due to historical aspects, as
9well as the desire in the early days to have the kernel itself be a
10bootable image, the complicated PC memory model and due to changed
11expectations in the PC industry caused by the effective demise of
12real-mode DOS as a mainstream operating system.
13
14Currently, four versions of the Linux/i386 boot protocol exist.
15
16Old kernels: zImage/Image support only. Some very early kernels
17 may not even support a command line.
18
19Protocol 2.00: (Kernel 1.3.73) Added bzImage and initrd support, as
20 well as a formalized way to communicate between the
21 boot loader and the kernel. setup.S made relocatable,
22 although the traditional setup area still assumed
23 writable.
24
25Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning.
26
27Protocol 2.02: (Kernel 2.4.0-test3-pre3) New command line protocol.
28 Lower the conventional memory ceiling. No overwrite
29 of the traditional setup area, thus making booting
30 safe for systems which use the EBDA from SMM or 32-bit
31 BIOS entry points. zImage deprecated but still
32 supported.
33
34Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible
35 initrd address available to the bootloader.
36
37
38**** MEMORY LAYOUT
39
40The traditional memory map for the kernel loader, used for Image or
41zImage kernels, typically looks like:
42
43 | |
440A0000 +------------------------+
45 | Reserved for BIOS | Do not use. Reserved for BIOS EBDA.
4609A000 +------------------------+
47 | Stack/heap/cmdline | For use by the kernel real-mode code.
48098000 +------------------------+
49 | Kernel setup | The kernel real-mode code.
50090200 +------------------------+
51 | Kernel boot sector | The kernel legacy boot sector.
52090000 +------------------------+
53 | Protected-mode kernel | The bulk of the kernel image.
54010000 +------------------------+
55 | Boot loader | <- Boot sector entry point 0000:7C00
56001000 +------------------------+
57 | Reserved for MBR/BIOS |
58000800 +------------------------+
59 | Typically used by MBR |
60000600 +------------------------+
61 | BIOS use only |
62000000 +------------------------+
63
64
65When using bzImage, the protected-mode kernel was relocated to
660x100000 ("high memory"), and the kernel real-mode block (boot sector,
67setup, and stack/heap) was made relocatable to any address between
680x10000 and end of low memory. Unfortunately, in protocols 2.00 and
692.01 the command line is still required to live in the 0x9XXXX memory
70range, and that memory range is still overwritten by the early kernel.
71The 2.02 protocol resolves that problem.
72
73It is desirable to keep the "memory ceiling" -- the highest point in
74low memory touched by the boot loader -- as low as possible, since
75some newer BIOSes have begun to allocate some rather large amounts of
76memory, called the Extended BIOS Data Area, near the top of low
77memory. The boot loader should use the "INT 12h" BIOS call to verify
78how much low memory is available.
79
80Unfortunately, if INT 12h reports that the amount of memory is too
81low, there is usually nothing the boot loader can do but to report an
82error to the user. The boot loader should therefore be designed to
83take up as little space in low memory as it reasonably can. For
84zImage or old bzImage kernels, which need data written into the
850x90000 segment, the boot loader should make sure not to use memory
86above the 0x9A000 point; too many BIOSes will break above that point.
87
88
89**** THE REAL-MODE KERNEL HEADER
90
91In the following text, and anywhere in the kernel boot sequence, "a
92sector" refers to 512 bytes. It is independent of the actual sector
93size of the underlying medium.
94
95The first step in loading a Linux kernel should be to load the
96real-mode code (boot sector and setup code) and then examine the
97following header at offset 0x01f1. The real-mode code can total up to
9832K, although the boot loader may choose to load only the first two
99sectors (1K) and then examine the bootup sector size.
100
101The header looks like:
102
103Offset Proto Name Meaning
104/Size
105
10601F1/1 ALL setup_sects The size of the setup in sectors
10701F2/2 ALL root_flags If set, the root is mounted readonly
10801F4/2 ALL syssize DO NOT USE - for bootsect.S use only
10901F6/2 ALL swap_dev DO NOT USE - obsolete
11001F8/2 ALL ram_size DO NOT USE - for bootsect.S use only
11101FA/2 ALL vid_mode Video mode control
11201FC/2 ALL root_dev Default root device number
11301FE/2 ALL boot_flag 0xAA55 magic number
1140200/2 2.00+ jump Jump instruction
1150202/4 2.00+ header Magic signature "HdrS"
1160206/2 2.00+ version Boot protocol version supported
1170208/4 2.00+ realmode_swtch Boot loader hook (see below)
118020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete)
119020E/2 2.00+ kernel_version Pointer to kernel version string
1200210/1 2.00+ type_of_loader Boot loader identifier
1210211/1 2.00+ loadflags Boot protocol option flags
1220212/2 2.00+ setup_move_size Move to high memory size (used with hooks)
1230214/4 2.00+ code32_start Boot loader hook (see below)
1240218/4 2.00+ ramdisk_image initrd load address (set by boot loader)
125021C/4 2.00+ ramdisk_size initrd size (set by boot loader)
1260220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only
1270224/2 2.01+ heap_end_ptr Free memory after setup end
1280226/2 N/A pad1 Unused
1290228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line
130022C/4 2.03+ initrd_addr_max Highest legal initrd address
131
132For backwards compatibility, if the setup_sects field contains 0, the
133real value is 4.
134
135If the "HdrS" (0x53726448) magic number is not found at offset 0x202,
136the boot protocol version is "old". Loading an old kernel, the
137following parameters should be assumed:
138
139 Image type = zImage
140 initrd not supported
141 Real-mode kernel must be located at 0x90000.
142
143Otherwise, the "version" field contains the protocol version,
144e.g. protocol version 2.01 will contain 0x0201 in this field. When
145setting fields in the header, you must make sure only to set fields
146supported by the protocol version in use.
147
148The "kernel_version" field, if set to a nonzero value, contains a
149pointer to a null-terminated human-readable kernel version number
150string, less 0x200. This can be used to display the kernel version to
151the user. This value should be less than (0x200*setup_sects). For
152example, if this value is set to 0x1c00, the kernel version number
153string can be found at offset 0x1e00 in the kernel file. This is a
154valid value if and only if the "setup_sects" field contains the value
15514 or higher.
156
157Most boot loaders will simply load the kernel at its target address
158directly. Such boot loaders do not need to worry about filling in
159most of the fields in the header. The following fields should be
160filled out, however:
161
162 vid_mode:
163 Please see the section on SPECIAL COMMAND LINE OPTIONS.
164
165 type_of_loader:
166 If your boot loader has an assigned id (see table below), enter
167 0xTV here, where T is an identifier for the boot loader and V is
168 a version number. Otherwise, enter 0xFF here.
169
170 Assigned boot loader ids:
171 0 LILO
172 1 Loadlin
173 2 bootsect-loader
174 3 SYSLINUX
175 4 EtherBoot
176 5 ELILO
177 7 GRuB
178 8 U-BOOT
179
180 Please contact <hpa@zytor.com> if you need a bootloader ID
181 value assigned.
182
183 loadflags, heap_end_ptr:
184 If the protocol version is 2.01 or higher, enter the
185 offset limit of the setup heap into heap_end_ptr and set the
186 0x80 bit (CAN_USE_HEAP) of loadflags. heap_end_ptr appears to
187 be relative to the start of setup (offset 0x0200).
188
189 setup_move_size:
190 When using protocol 2.00 or 2.01, if the real mode
191 kernel is not loaded at 0x90000, it gets moved there later in
192 the loading sequence. Fill in this field if you want
193 additional data (such as the kernel command line) moved in
194 addition to the real-mode kernel itself.
195
196 ramdisk_image, ramdisk_size:
197 If your boot loader has loaded an initial ramdisk (initrd),
198 set ramdisk_image to the 32-bit pointer to the ramdisk data
199 and the ramdisk_size to the size of the ramdisk data.
200
201 The initrd should typically be located as high in memory as
202 possible, as it may otherwise get overwritten by the early
203 kernel initialization sequence. However, it must never be
204 located above the address specified in the initrd_addr_max
205 field. The initrd should be at least 4K page aligned.
206
207 cmd_line_ptr:
208 If the protocol version is 2.02 or higher, this is a 32-bit
209 pointer to the kernel command line. The kernel command line
210 can be located anywhere between the end of setup and 0xA0000.
211 Fill in this field even if your boot loader does not support a
212 command line, in which case you can point this to an empty
213 string (or better yet, to the string "auto".) If this field
214 is left at zero, the kernel will assume that your boot loader
215 does not support the 2.02+ protocol.
216
217 ramdisk_max:
218 The maximum address that may be occupied by the initrd
219 contents. For boot protocols 2.02 or earlier, this field is
220 not present, and the maximum address is 0x37FFFFFF. (This
221 address is defined as the address of the highest safe byte, so
222 if your ramdisk is exactly 131072 bytes long and this field is
223 0x37FFFFFF, you can start your ramdisk at 0x37FE0000.)
224
225
226**** THE KERNEL COMMAND LINE
227
228The kernel command line has become an important way for the boot
229loader to communicate with the kernel. Some of its options are also
230relevant to the boot loader itself, see "special command line options"
231below.
232
233The kernel command line is a null-terminated string up to 255
234characters long, plus the final null.
235
236If the boot protocol version is 2.02 or later, the address of the
237kernel command line is given by the header field cmd_line_ptr (see
238above.)
239
240If the protocol version is *not* 2.02 or higher, the kernel
241command line is entered using the following protocol:
242
243 At offset 0x0020 (word), "cmd_line_magic", enter the magic
244 number 0xA33F.
245
246 At offset 0x0022 (word), "cmd_line_offset", enter the offset
247 of the kernel command line (relative to the start of the
248 real-mode kernel).
249
250 The kernel command line *must* be within the memory region
251 covered by setup_move_size, so you may need to adjust this
252 field.
253
254
255**** SAMPLE BOOT CONFIGURATION
256
257As a sample configuration, assume the following layout of the real
258mode segment:
259
260 0x0000-0x7FFF Real mode kernel
261 0x8000-0x8FFF Stack and heap
262 0x9000-0x90FF Kernel command line
263
264Such a boot loader should enter the following fields in the header:
265
266 unsigned long base_ptr; /* base address for real-mode segment */
267
268 if ( setup_sects == 0 ) {
269 setup_sects = 4;
270 }
271
272 if ( protocol >= 0x0200 ) {
273 type_of_loader = <type code>;
274 if ( loading_initrd ) {
275 ramdisk_image = <initrd_address>;
276 ramdisk_size = <initrd_size>;
277 }
278 if ( protocol >= 0x0201 ) {
279 heap_end_ptr = 0x9000 - 0x200;
280 loadflags |= 0x80; /* CAN_USE_HEAP */
281 }
282 if ( protocol >= 0x0202 ) {
283 cmd_line_ptr = base_ptr + 0x9000;
284 } else {
285 cmd_line_magic = 0xA33F;
286 cmd_line_offset = 0x9000;
287 setup_move_size = 0x9100;
288 }
289 } else {
290 /* Very old kernel */
291
292 cmd_line_magic = 0xA33F;
293 cmd_line_offset = 0x9000;
294
295 /* A very old kernel MUST have its real-mode code
296 loaded at 0x90000 */
297
298 if ( base_ptr != 0x90000 ) {
299 /* Copy the real-mode kernel */
300 memcpy(0x90000, base_ptr, (setup_sects+1)*512);
301 /* Copy the command line */
302 memcpy(0x99000, base_ptr+0x9000, 256);
303
304 base_ptr = 0x90000; /* Relocated */
305 }
306
307 /* It is recommended to clear memory up to the 32K mark */
308 memset(0x90000 + (setup_sects+1)*512, 0,
309 (64-(setup_sects+1))*512);
310 }
311
312
313**** LOADING THE REST OF THE KERNEL
314
315The non-real-mode kernel starts at offset (setup_sects+1)*512 in the
316kernel file (again, if setup_sects == 0 the real value is 4.) It
317should be loaded at address 0x10000 for Image/zImage kernels and
3180x100000 for bzImage kernels.
319
320The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01
321bit (LOAD_HIGH) in the loadflags field is set:
322
323 is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01);
324 load_address = is_bzImage ? 0x100000 : 0x10000;
325
326Note that Image/zImage kernels can be up to 512K in size, and thus use
327the entire 0x10000-0x90000 range of memory. This means it is pretty
328much a requirement for these kernels to load the real-mode part at
3290x90000. bzImage kernels allow much more flexibility.
330
331
332**** SPECIAL COMMAND LINE OPTIONS
333
334If the command line provided by the boot loader is entered by the
335user, the user may expect the following command line options to work.
336They should normally not be deleted from the kernel command line even
337though not all of them are actually meaningful to the kernel. Boot
338loader authors who need additional command line options for the boot
339loader itself should get them registered in
340Documentation/kernel-parameters.txt to make sure they will not
341conflict with actual kernel options now or in the future.
342
343 vga=<mode>
344 <mode> here is either an integer (in C notation, either
345 decimal, octal, or hexadecimal) or one of the strings
346 "normal" (meaning 0xFFFF), "ext" (meaning 0xFFFE) or "ask"
347 (meaning 0xFFFD). This value should be entered into the
348 vid_mode field, as it is used by the kernel before the command
349 line is parsed.
350
351 mem=<size>
352 <size> is an integer in C notation optionally followed by K, M
353 or G (meaning << 10, << 20 or << 30). This specifies the end
354 of memory to the kernel. This affects the possible placement
355 of an initrd, since an initrd should be placed near end of
356 memory. Note that this is an option to *both* the kernel and
357 the bootloader!
358
359 initrd=<file>
360 An initrd should be loaded. The meaning of <file> is
361 obviously bootloader-dependent, and some boot loaders
362 (e.g. LILO) do not have such a command.
363
364In addition, some boot loaders add the following options to the
365user-specified command line:
366
367 BOOT_IMAGE=<file>
368 The boot image which was loaded. Again, the meaning of <file>
369 is obviously bootloader-dependent.
370
371 auto
372 The kernel was booted without explicit user intervention.
373
374If these options are added by the boot loader, it is highly
375recommended that they are located *first*, before the user-specified
376or configuration-specified command line. Otherwise, "init=/bin/sh"
377gets confused by the "auto" option.
378
379
380**** RUNNING THE KERNEL
381
382The kernel is started by jumping to the kernel entry point, which is
383located at *segment* offset 0x20 from the start of the real mode
384kernel. This means that if you loaded your real-mode kernel code at
3850x90000, the kernel entry point is 9020:0000.
386
387At entry, ds = es = ss should point to the start of the real-mode
388kernel code (0x9000 if the code is loaded at 0x90000), sp should be
389set up properly, normally pointing to the top of the heap, and
390interrupts should be disabled. Furthermore, to guard against bugs in
391the kernel, it is recommended that the boot loader sets fs = gs = ds =
392es = ss.
393
394In our example from above, we would do:
395
396 /* Note: in the case of the "old" kernel protocol, base_ptr must
397 be == 0x90000 at this point; see the previous sample code */
398
399 seg = base_ptr >> 4;
400
401 cli(); /* Enter with interrupts disabled! */
402
403 /* Set up the real-mode kernel stack */
404 _SS = seg;
405 _SP = 0x9000; /* Load SP immediately after loading SS! */
406
407 _DS = _ES = _FS = _GS = seg;
408 jmp_far(seg+0x20, 0); /* Run the kernel */
409
410If your boot sector accesses a floppy drive, it is recommended to
411switch off the floppy motor before running the kernel, since the
412kernel boot leaves interrupts off and thus the motor will not be
413switched off, especially if the loaded kernel has the floppy driver as
414a demand-loaded module!
415
416
417**** ADVANCED BOOT TIME HOOKS
418
419If the boot loader runs in a particularly hostile environment (such as
420LOADLIN, which runs under DOS) it may be impossible to follow the
421standard memory location requirements. Such a boot loader may use the
422following hooks that, if set, are invoked by the kernel at the
423appropriate time. The use of these hooks should probably be
424considered an absolutely last resort!
425
426IMPORTANT: All the hooks are required to preserve %esp, %ebp, %esi and
427%edi across invocation.
428
429 realmode_swtch:
430 A 16-bit real mode far subroutine invoked immediately before
431 entering protected mode. The default routine disables NMI, so
432 your routine should probably do so, too.
433
434 code32_start:
435 A 32-bit flat-mode routine *jumped* to immediately after the
436 transition to protected mode, but before the kernel is
437 uncompressed. No segments, except CS, are set up; you should
438 set them up to KERNEL_DS (0x18) yourself.
439
440 After completing your hook, you should jump to the address
441 that was in this field before your boot loader overwrote it.
diff --git a/Documentation/i386/usb-legacy-support.txt b/Documentation/i386/usb-legacy-support.txt
new file mode 100644
index 000000000000..1894cdfc69d9
--- /dev/null
+++ b/Documentation/i386/usb-legacy-support.txt
@@ -0,0 +1,44 @@
1USB Legacy support
2~~~~~~~~~~~~~~~~~~
3
4Vojtech Pavlik <vojtech@suse.cz>, January 2004
5
6
7Also known as "USB Keyboard" or "USB Mouse support" in the BIOS Setup is a
8feature that allows one to use the USB mouse and keyboard as if they were
9their classic PS/2 counterparts. This means one can use an USB keyboard to
10type in LILO for example.
11
12It has several drawbacks, though:
13
141) On some machines, the emulated PS/2 mouse takes over even when no USB
15 mouse is present and a real PS/2 mouse is present. In that case the extra
16 features (wheel, extra buttons, touchpad mode) of the real PS/2 mouse may
17 not be available.
18
192) If CONFIG_HIGHMEM64G is enabled, the PS/2 mouse emulation can cause
20 system crashes, because the SMM BIOS is not expecting to be in PAE mode.
21 The Intel E7505 is a typical machine where this happens.
22
233) If AMD64 64-bit mode is enabled, again system crashes often happen,
24 because the SMM BIOS isn't expecting the CPU to be in 64-bit mode. The
25 BIOS manufacturers only test with Windows, and Windows doesn't do 64-bit
26 yet.
27
28Solutions:
29
30Problem 1) can be solved by loading the USB drivers prior to loading the
31PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into
32the kernel unconditionally, this means the USB drivers need to be
33compiled-in, too.
34
35Problem 2) can currently only be solved by either disabling HIGHMEM64G
36in the kernel config or USB Legacy support in the BIOS. A BIOS update
37could help, but so far no such update exists.
38
39Problem 3) is usually fixed by a BIOS update. Check the board
40manufacturers web site. If an update is not available, disable USB
41Legacy support in the BIOS. If this alone doesn't help, try also adding
42idle=poll on the kernel command line. The BIOS may be entering the SMM
43on the HLT instruction as well.
44
diff --git a/Documentation/i386/zero-page.txt b/Documentation/i386/zero-page.txt
new file mode 100644
index 000000000000..67c053a099ed
--- /dev/null
+++ b/Documentation/i386/zero-page.txt
@@ -0,0 +1,84 @@
1Summary of boot_params layout (kernel point of view)
2 ( collected by Hans Lermen and Martin Mares )
3
4The contents of boot_params are used to pass parameters from the
516-bit realmode code of the kernel to the 32-bit part. References/settings
6to it mainly are in:
7
8 arch/i386/boot/setup.S
9 arch/i386/boot/video.S
10 arch/i386/kernel/head.S
11 arch/i386/kernel/setup.c
12
13
14Offset Type Description
15------ ---- -----------
16 0 32 bytes struct screen_info, SCREEN_INFO
17 ATTENTION, overlaps the following !!!
18 2 unsigned short EXT_MEM_K, extended memory size in Kb (from int 0x15)
19 0x20 unsigned short CL_MAGIC, commandline magic number (=0xA33F)
20 0x22 unsigned short CL_OFFSET, commandline offset
21 Address of commandline is calculated:
22 0x90000 + contents of CL_OFFSET
23 (only taken, when CL_MAGIC = 0xA33F)
24 0x40 20 bytes struct apm_bios_info, APM_BIOS_INFO
25 0x60 16 bytes Intel SpeedStep (IST) BIOS support information
26 0x80 16 bytes hd0-disk-parameter from intvector 0x41
27 0x90 16 bytes hd1-disk-parameter from intvector 0x46
28
29 0xa0 16 bytes System description table truncated to 16 bytes.
30 ( struct sys_desc_table_struct )
31 0xb0 - 0x13f Free. Add more parameters here if you really need them.
32 0x140- 0x1be EDID_INFO Video mode setup
33
340x1c4 unsigned long EFI system table pointer
350x1c8 unsigned long EFI memory descriptor size
360x1cc unsigned long EFI memory descriptor version
370x1d0 unsigned long EFI memory descriptor map pointer
380x1d4 unsigned long EFI memory descriptor map size
390x1e0 unsigned long ALT_MEM_K, alternative mem check, in Kb
400x1e8 char number of entries in E820MAP (below)
410x1e9 unsigned char number of entries in EDDBUF (below)
420x1ea unsigned char number of entries in EDD_MBR_SIG_BUFFER (below)
430x1f1 char size of setup.S, number of sectors
440x1f2 unsigned short MOUNT_ROOT_RDONLY (if !=0)
450x1f4 unsigned short size of compressed kernel-part in the
46 (b)zImage-file (in 16 byte units, rounded up)
470x1f6 unsigned short swap_dev (unused AFAIK)
480x1f8 unsigned short RAMDISK_FLAGS
490x1fa unsigned short VGA-Mode (old one)
500x1fc unsigned short ORIG_ROOT_DEV (high=Major, low=minor)
510x1ff char AUX_DEVICE_INFO
52
530x200 short jump to start of setup code aka "reserved" field.
540x202 4 bytes Signature for SETUP-header, ="HdrS"
550x206 unsigned short Version number of header format
56 Current version is 0x0201...
570x208 8 bytes (used by setup.S for communication with boot loaders,
58 look there)
590x210 char LOADER_TYPE, = 0, old one
60 else it is set by the loader:
61 0xTV: T=0 for LILO
62 1 for Loadlin
63 2 for bootsect-loader
64 3 for SYSLINUX
65 4 for ETHERBOOT
66 V = version
670x211 char loadflags:
68 bit0 = 1: kernel is loaded high (bzImage)
69 bit7 = 1: Heap and pointer (see below) set by boot
70 loader.
710x212 unsigned short (setup.S)
720x214 unsigned long KERNEL_START, where the loader started the kernel
730x218 unsigned long INITRD_START, address of loaded ramdisk image
740x21c unsigned long INITRD_SIZE, size in bytes of ramdisk image
750x220 4 bytes (setup.S)
760x224 unsigned short setup.S heap end pointer
770x226 unsigned short zero_pad
780x228 unsigned long cmd_line_ptr
790x22c unsigned long ramdisk_max
800x230 16 bytes trampoline
810x290 - 0x2cf EDD_MBR_SIG_BUFFER (edd.S)
820x2d0 - 0x600 E820MAP
830x600 - 0x7ff EDDBUF (edd.S) for disk signature read sector
840x600 - 0x7eb EDDBUF (edd.S) for edd data