diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /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.txt | 117 | ||||
-rw-r--r-- | Documentation/i386/boot.txt | 441 | ||||
-rw-r--r-- | Documentation/i386/usb-legacy-support.txt | 44 | ||||
-rw-r--r-- | Documentation/i386/zero-page.txt | 84 |
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 @@ | |||
1 | Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC', | ||
2 | which is an enhanced interrupt controller, it enables us to route | ||
3 | hardware interrupts to multiple CPUs, or to CPU groups. | ||
4 | |||
5 | Linux supports all variants of compliant SMP boards, including ones with | ||
6 | multiple IO-APICs. (multiple IO-APICs are used in high-end servers to | ||
7 | distribute IRQ load further). | ||
8 | |||
9 | There are (a few) known breakages in certain older boards, which bugs are | ||
10 | usually worked around by the kernel. If your MP-compliant SMP board does | ||
11 | not boot Linux, then consult the linux-smp mailing list archives first. | ||
12 | |||
13 | If 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 | |||
31 | some interrupts are still listed as 'XT PIC', but this is not a problem, | ||
32 | none of those IRQ sources is performance-critical. | ||
33 | |||
34 | |||
35 | in the unlikely case that your board does not create a working mp-table, | ||
36 | you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This | ||
37 | is nontrivial though and cannot be automated. One sample /etc/lilo.conf | ||
38 | entry: | ||
39 | |||
40 | append="pirq=15,11,10" | ||
41 | |||
42 | the actual numbers depend on your system, on your PCI cards and on their | ||
43 | PCI slot position. Usually PCI slots are 'daisy chained' before they are | ||
44 | connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4 | ||
45 | lines): | ||
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 | |||
57 | every 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 | |||
69 | These INTA-D PCI IRQs are always 'local to the card', their real meaning | ||
70 | depends on which slot they are in. If you look at the daisy chaining diagram, | ||
71 | a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ2 of | ||
72 | the PCI chipset. Most cards issue INTA, this creates optimal distribution | ||
73 | between the PIRQ lines. (distributing IRQ sources properly is not a | ||
74 | necessity, PCI IRQs can be shared at will, but it's a good for performance | ||
75 | to have non shared interrupts). Slot5 should be used for videocards, they | ||
76 | do not use interrupts normally, thus they are not daisy chained either. | ||
77 | |||
78 | so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in | ||
79 | Slot2, then you'll have to specify this pirq= line: | ||
80 | |||
81 | append="pirq=11,9" | ||
82 | |||
83 | the following script tries to figure out such a default pirq= line from | ||
84 | your PCI configuration: | ||
85 | |||
86 | echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g' | ||
87 | |||
88 | note that this script wont work if you have skipped a few slots or if your | ||
89 | board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins | ||
90 | connected in some strange way). E.g. if in the above case you have your SCSI | ||
91 | card (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) | ||
96 | slots.] | ||
97 | |||
98 | generally, it's always possible to find out the correct pirq= settings, just | ||
99 | permute 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 | ||
101 | won't function properly (if it's inserted as eg. a module). | ||
102 | |||
103 | If you have 2 PCI buses, then you can use up to 8 pirq values. Although such | ||
104 | boards tend to have a good configuration. | ||
105 | |||
106 | Be 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 | |||
110 | use smart try-and-err techniques to find out the correct pirq line ... | ||
111 | |||
112 | good luck and mail to linux-smp@vger.kernel.org or | ||
113 | linux-kernel@vger.kernel.org if you have any problems that are not covered | ||
114 | by 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 | |||
7 | On the i386 platform, the Linux kernel uses a rather complicated boot | ||
8 | convention. This has evolved partially due to historical aspects, as | ||
9 | well as the desire in the early days to have the kernel itself be a | ||
10 | bootable image, the complicated PC memory model and due to changed | ||
11 | expectations in the PC industry caused by the effective demise of | ||
12 | real-mode DOS as a mainstream operating system. | ||
13 | |||
14 | Currently, four versions of the Linux/i386 boot protocol exist. | ||
15 | |||
16 | Old kernels: zImage/Image support only. Some very early kernels | ||
17 | may not even support a command line. | ||
18 | |||
19 | Protocol 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 | |||
25 | Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning. | ||
26 | |||
27 | Protocol 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 | |||
34 | Protocol 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 | |||
40 | The traditional memory map for the kernel loader, used for Image or | ||
41 | zImage kernels, typically looks like: | ||
42 | |||
43 | | | | ||
44 | 0A0000 +------------------------+ | ||
45 | | Reserved for BIOS | Do not use. Reserved for BIOS EBDA. | ||
46 | 09A000 +------------------------+ | ||
47 | | Stack/heap/cmdline | For use by the kernel real-mode code. | ||
48 | 098000 +------------------------+ | ||
49 | | Kernel setup | The kernel real-mode code. | ||
50 | 090200 +------------------------+ | ||
51 | | Kernel boot sector | The kernel legacy boot sector. | ||
52 | 090000 +------------------------+ | ||
53 | | Protected-mode kernel | The bulk of the kernel image. | ||
54 | 010000 +------------------------+ | ||
55 | | Boot loader | <- Boot sector entry point 0000:7C00 | ||
56 | 001000 +------------------------+ | ||
57 | | Reserved for MBR/BIOS | | ||
58 | 000800 +------------------------+ | ||
59 | | Typically used by MBR | | ||
60 | 000600 +------------------------+ | ||
61 | | BIOS use only | | ||
62 | 000000 +------------------------+ | ||
63 | |||
64 | |||
65 | When using bzImage, the protected-mode kernel was relocated to | ||
66 | 0x100000 ("high memory"), and the kernel real-mode block (boot sector, | ||
67 | setup, and stack/heap) was made relocatable to any address between | ||
68 | 0x10000 and end of low memory. Unfortunately, in protocols 2.00 and | ||
69 | 2.01 the command line is still required to live in the 0x9XXXX memory | ||
70 | range, and that memory range is still overwritten by the early kernel. | ||
71 | The 2.02 protocol resolves that problem. | ||
72 | |||
73 | It is desirable to keep the "memory ceiling" -- the highest point in | ||
74 | low memory touched by the boot loader -- as low as possible, since | ||
75 | some newer BIOSes have begun to allocate some rather large amounts of | ||
76 | memory, called the Extended BIOS Data Area, near the top of low | ||
77 | memory. The boot loader should use the "INT 12h" BIOS call to verify | ||
78 | how much low memory is available. | ||
79 | |||
80 | Unfortunately, if INT 12h reports that the amount of memory is too | ||
81 | low, there is usually nothing the boot loader can do but to report an | ||
82 | error to the user. The boot loader should therefore be designed to | ||
83 | take up as little space in low memory as it reasonably can. For | ||
84 | zImage or old bzImage kernels, which need data written into the | ||
85 | 0x90000 segment, the boot loader should make sure not to use memory | ||
86 | above the 0x9A000 point; too many BIOSes will break above that point. | ||
87 | |||
88 | |||
89 | **** THE REAL-MODE KERNEL HEADER | ||
90 | |||
91 | In the following text, and anywhere in the kernel boot sequence, "a | ||
92 | sector" refers to 512 bytes. It is independent of the actual sector | ||
93 | size of the underlying medium. | ||
94 | |||
95 | The first step in loading a Linux kernel should be to load the | ||
96 | real-mode code (boot sector and setup code) and then examine the | ||
97 | following header at offset 0x01f1. The real-mode code can total up to | ||
98 | 32K, although the boot loader may choose to load only the first two | ||
99 | sectors (1K) and then examine the bootup sector size. | ||
100 | |||
101 | The header looks like: | ||
102 | |||
103 | Offset Proto Name Meaning | ||
104 | /Size | ||
105 | |||
106 | 01F1/1 ALL setup_sects The size of the setup in sectors | ||
107 | 01F2/2 ALL root_flags If set, the root is mounted readonly | ||
108 | 01F4/2 ALL syssize DO NOT USE - for bootsect.S use only | ||
109 | 01F6/2 ALL swap_dev DO NOT USE - obsolete | ||
110 | 01F8/2 ALL ram_size DO NOT USE - for bootsect.S use only | ||
111 | 01FA/2 ALL vid_mode Video mode control | ||
112 | 01FC/2 ALL root_dev Default root device number | ||
113 | 01FE/2 ALL boot_flag 0xAA55 magic number | ||
114 | 0200/2 2.00+ jump Jump instruction | ||
115 | 0202/4 2.00+ header Magic signature "HdrS" | ||
116 | 0206/2 2.00+ version Boot protocol version supported | ||
117 | 0208/4 2.00+ realmode_swtch Boot loader hook (see below) | ||
118 | 020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete) | ||
119 | 020E/2 2.00+ kernel_version Pointer to kernel version string | ||
120 | 0210/1 2.00+ type_of_loader Boot loader identifier | ||
121 | 0211/1 2.00+ loadflags Boot protocol option flags | ||
122 | 0212/2 2.00+ setup_move_size Move to high memory size (used with hooks) | ||
123 | 0214/4 2.00+ code32_start Boot loader hook (see below) | ||
124 | 0218/4 2.00+ ramdisk_image initrd load address (set by boot loader) | ||
125 | 021C/4 2.00+ ramdisk_size initrd size (set by boot loader) | ||
126 | 0220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only | ||
127 | 0224/2 2.01+ heap_end_ptr Free memory after setup end | ||
128 | 0226/2 N/A pad1 Unused | ||
129 | 0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line | ||
130 | 022C/4 2.03+ initrd_addr_max Highest legal initrd address | ||
131 | |||
132 | For backwards compatibility, if the setup_sects field contains 0, the | ||
133 | real value is 4. | ||
134 | |||
135 | If the "HdrS" (0x53726448) magic number is not found at offset 0x202, | ||
136 | the boot protocol version is "old". Loading an old kernel, the | ||
137 | following parameters should be assumed: | ||
138 | |||
139 | Image type = zImage | ||
140 | initrd not supported | ||
141 | Real-mode kernel must be located at 0x90000. | ||
142 | |||
143 | Otherwise, the "version" field contains the protocol version, | ||
144 | e.g. protocol version 2.01 will contain 0x0201 in this field. When | ||
145 | setting fields in the header, you must make sure only to set fields | ||
146 | supported by the protocol version in use. | ||
147 | |||
148 | The "kernel_version" field, if set to a nonzero value, contains a | ||
149 | pointer to a null-terminated human-readable kernel version number | ||
150 | string, less 0x200. This can be used to display the kernel version to | ||
151 | the user. This value should be less than (0x200*setup_sects). For | ||
152 | example, if this value is set to 0x1c00, the kernel version number | ||
153 | string can be found at offset 0x1e00 in the kernel file. This is a | ||
154 | valid value if and only if the "setup_sects" field contains the value | ||
155 | 14 or higher. | ||
156 | |||
157 | Most boot loaders will simply load the kernel at its target address | ||
158 | directly. Such boot loaders do not need to worry about filling in | ||
159 | most of the fields in the header. The following fields should be | ||
160 | filled 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 | |||
228 | The kernel command line has become an important way for the boot | ||
229 | loader to communicate with the kernel. Some of its options are also | ||
230 | relevant to the boot loader itself, see "special command line options" | ||
231 | below. | ||
232 | |||
233 | The kernel command line is a null-terminated string up to 255 | ||
234 | characters long, plus the final null. | ||
235 | |||
236 | If the boot protocol version is 2.02 or later, the address of the | ||
237 | kernel command line is given by the header field cmd_line_ptr (see | ||
238 | above.) | ||
239 | |||
240 | If the protocol version is *not* 2.02 or higher, the kernel | ||
241 | command 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 | |||
257 | As a sample configuration, assume the following layout of the real | ||
258 | mode segment: | ||
259 | |||
260 | 0x0000-0x7FFF Real mode kernel | ||
261 | 0x8000-0x8FFF Stack and heap | ||
262 | 0x9000-0x90FF Kernel command line | ||
263 | |||
264 | Such 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 | |||
315 | The non-real-mode kernel starts at offset (setup_sects+1)*512 in the | ||
316 | kernel file (again, if setup_sects == 0 the real value is 4.) It | ||
317 | should be loaded at address 0x10000 for Image/zImage kernels and | ||
318 | 0x100000 for bzImage kernels. | ||
319 | |||
320 | The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01 | ||
321 | bit (LOAD_HIGH) in the loadflags field is set: | ||
322 | |||
323 | is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01); | ||
324 | load_address = is_bzImage ? 0x100000 : 0x10000; | ||
325 | |||
326 | Note that Image/zImage kernels can be up to 512K in size, and thus use | ||
327 | the entire 0x10000-0x90000 range of memory. This means it is pretty | ||
328 | much a requirement for these kernels to load the real-mode part at | ||
329 | 0x90000. bzImage kernels allow much more flexibility. | ||
330 | |||
331 | |||
332 | **** SPECIAL COMMAND LINE OPTIONS | ||
333 | |||
334 | If the command line provided by the boot loader is entered by the | ||
335 | user, the user may expect the following command line options to work. | ||
336 | They should normally not be deleted from the kernel command line even | ||
337 | though not all of them are actually meaningful to the kernel. Boot | ||
338 | loader authors who need additional command line options for the boot | ||
339 | loader itself should get them registered in | ||
340 | Documentation/kernel-parameters.txt to make sure they will not | ||
341 | conflict 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 | |||
364 | In addition, some boot loaders add the following options to the | ||
365 | user-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 | |||
374 | If these options are added by the boot loader, it is highly | ||
375 | recommended that they are located *first*, before the user-specified | ||
376 | or configuration-specified command line. Otherwise, "init=/bin/sh" | ||
377 | gets confused by the "auto" option. | ||
378 | |||
379 | |||
380 | **** RUNNING THE KERNEL | ||
381 | |||
382 | The kernel is started by jumping to the kernel entry point, which is | ||
383 | located at *segment* offset 0x20 from the start of the real mode | ||
384 | kernel. This means that if you loaded your real-mode kernel code at | ||
385 | 0x90000, the kernel entry point is 9020:0000. | ||
386 | |||
387 | At entry, ds = es = ss should point to the start of the real-mode | ||
388 | kernel code (0x9000 if the code is loaded at 0x90000), sp should be | ||
389 | set up properly, normally pointing to the top of the heap, and | ||
390 | interrupts should be disabled. Furthermore, to guard against bugs in | ||
391 | the kernel, it is recommended that the boot loader sets fs = gs = ds = | ||
392 | es = ss. | ||
393 | |||
394 | In 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 | |||
410 | If your boot sector accesses a floppy drive, it is recommended to | ||
411 | switch off the floppy motor before running the kernel, since the | ||
412 | kernel boot leaves interrupts off and thus the motor will not be | ||
413 | switched off, especially if the loaded kernel has the floppy driver as | ||
414 | a demand-loaded module! | ||
415 | |||
416 | |||
417 | **** ADVANCED BOOT TIME HOOKS | ||
418 | |||
419 | If the boot loader runs in a particularly hostile environment (such as | ||
420 | LOADLIN, which runs under DOS) it may be impossible to follow the | ||
421 | standard memory location requirements. Such a boot loader may use the | ||
422 | following hooks that, if set, are invoked by the kernel at the | ||
423 | appropriate time. The use of these hooks should probably be | ||
424 | considered an absolutely last resort! | ||
425 | |||
426 | IMPORTANT: 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 @@ | |||
1 | USB Legacy support | ||
2 | ~~~~~~~~~~~~~~~~~~ | ||
3 | |||
4 | Vojtech Pavlik <vojtech@suse.cz>, January 2004 | ||
5 | |||
6 | |||
7 | Also known as "USB Keyboard" or "USB Mouse support" in the BIOS Setup is a | ||
8 | feature that allows one to use the USB mouse and keyboard as if they were | ||
9 | their classic PS/2 counterparts. This means one can use an USB keyboard to | ||
10 | type in LILO for example. | ||
11 | |||
12 | It has several drawbacks, though: | ||
13 | |||
14 | 1) 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 | |||
19 | 2) 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 | |||
23 | 3) 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 | |||
28 | Solutions: | ||
29 | |||
30 | Problem 1) can be solved by loading the USB drivers prior to loading the | ||
31 | PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into | ||
32 | the kernel unconditionally, this means the USB drivers need to be | ||
33 | compiled-in, too. | ||
34 | |||
35 | Problem 2) can currently only be solved by either disabling HIGHMEM64G | ||
36 | in the kernel config or USB Legacy support in the BIOS. A BIOS update | ||
37 | could help, but so far no such update exists. | ||
38 | |||
39 | Problem 3) is usually fixed by a BIOS update. Check the board | ||
40 | manufacturers web site. If an update is not available, disable USB | ||
41 | Legacy support in the BIOS. If this alone doesn't help, try also adding | ||
42 | idle=poll on the kernel command line. The BIOS may be entering the SMM | ||
43 | on 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 @@ | |||
1 | Summary of boot_params layout (kernel point of view) | ||
2 | ( collected by Hans Lermen and Martin Mares ) | ||
3 | |||
4 | The contents of boot_params are used to pass parameters from the | ||
5 | 16-bit realmode code of the kernel to the 32-bit part. References/settings | ||
6 | to 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 | |||
14 | Offset 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 | |||
34 | 0x1c4 unsigned long EFI system table pointer | ||
35 | 0x1c8 unsigned long EFI memory descriptor size | ||
36 | 0x1cc unsigned long EFI memory descriptor version | ||
37 | 0x1d0 unsigned long EFI memory descriptor map pointer | ||
38 | 0x1d4 unsigned long EFI memory descriptor map size | ||
39 | 0x1e0 unsigned long ALT_MEM_K, alternative mem check, in Kb | ||
40 | 0x1e8 char number of entries in E820MAP (below) | ||
41 | 0x1e9 unsigned char number of entries in EDDBUF (below) | ||
42 | 0x1ea unsigned char number of entries in EDD_MBR_SIG_BUFFER (below) | ||
43 | 0x1f1 char size of setup.S, number of sectors | ||
44 | 0x1f2 unsigned short MOUNT_ROOT_RDONLY (if !=0) | ||
45 | 0x1f4 unsigned short size of compressed kernel-part in the | ||
46 | (b)zImage-file (in 16 byte units, rounded up) | ||
47 | 0x1f6 unsigned short swap_dev (unused AFAIK) | ||
48 | 0x1f8 unsigned short RAMDISK_FLAGS | ||
49 | 0x1fa unsigned short VGA-Mode (old one) | ||
50 | 0x1fc unsigned short ORIG_ROOT_DEV (high=Major, low=minor) | ||
51 | 0x1ff char AUX_DEVICE_INFO | ||
52 | |||
53 | 0x200 short jump to start of setup code aka "reserved" field. | ||
54 | 0x202 4 bytes Signature for SETUP-header, ="HdrS" | ||
55 | 0x206 unsigned short Version number of header format | ||
56 | Current version is 0x0201... | ||
57 | 0x208 8 bytes (used by setup.S for communication with boot loaders, | ||
58 | look there) | ||
59 | 0x210 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 | ||
67 | 0x211 char loadflags: | ||
68 | bit0 = 1: kernel is loaded high (bzImage) | ||
69 | bit7 = 1: Heap and pointer (see below) set by boot | ||
70 | loader. | ||
71 | 0x212 unsigned short (setup.S) | ||
72 | 0x214 unsigned long KERNEL_START, where the loader started the kernel | ||
73 | 0x218 unsigned long INITRD_START, address of loaded ramdisk image | ||
74 | 0x21c unsigned long INITRD_SIZE, size in bytes of ramdisk image | ||
75 | 0x220 4 bytes (setup.S) | ||
76 | 0x224 unsigned short setup.S heap end pointer | ||
77 | 0x226 unsigned short zero_pad | ||
78 | 0x228 unsigned long cmd_line_ptr | ||
79 | 0x22c unsigned long ramdisk_max | ||
80 | 0x230 16 bytes trampoline | ||
81 | 0x290 - 0x2cf EDD_MBR_SIG_BUFFER (edd.S) | ||
82 | 0x2d0 - 0x600 E820MAP | ||
83 | 0x600 - 0x7ff EDDBUF (edd.S) for disk signature read sector | ||
84 | 0x600 - 0x7eb EDDBUF (edd.S) for edd data | ||