diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-07-08 03:43:01 -0400 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 03:43:01 -0400 |
commit | 3c1ca43fafea41e38cb2d0c1684119af4c1de547 (patch) | |
tree | 122e41a7b9fca26ea25ea9864180f5016274a8c8 /Documentation/x86 | |
parent | 6924d1ab8b7bbe5ab416713f5701b3316b2df85b (diff) | |
parent | 6bcb13b35a2ea39be6c7cc0292b8ad1191b1a748 (diff) |
Merge branch 'x86/setup' into x86/devel
Diffstat (limited to 'Documentation/x86')
-rw-r--r-- | Documentation/x86/i386/IO-APIC.txt | 119 | ||||
-rw-r--r-- | Documentation/x86/i386/boot.txt | 900 | ||||
-rw-r--r-- | Documentation/x86/i386/usb-legacy-support.txt | 44 | ||||
-rw-r--r-- | Documentation/x86/i386/zero-page.txt | 31 | ||||
-rw-r--r-- | Documentation/x86/x86_64/00-INDEX | 16 | ||||
-rw-r--r-- | Documentation/x86/x86_64/boot-options.txt | 314 | ||||
-rw-r--r-- | Documentation/x86/x86_64/cpu-hotplug-spec | 21 | ||||
-rw-r--r-- | Documentation/x86/x86_64/fake-numa-for-cpusets | 66 | ||||
-rw-r--r-- | Documentation/x86/x86_64/kernel-stacks | 99 | ||||
-rw-r--r-- | Documentation/x86/x86_64/machinecheck | 77 | ||||
-rw-r--r-- | Documentation/x86/x86_64/mm.txt | 28 | ||||
-rw-r--r-- | Documentation/x86/x86_64/uefi.txt | 38 |
12 files changed, 1753 insertions, 0 deletions
diff --git a/Documentation/x86/i386/IO-APIC.txt b/Documentation/x86/i386/IO-APIC.txt new file mode 100644 index 000000000000..30b4c714fbe1 --- /dev/null +++ b/Documentation/x86/i386/IO-APIC.txt | |||
@@ -0,0 +1,119 @@ | |||
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. Without an | ||
4 | IO-APIC, interrupts from hardware will be delivered only to the | ||
5 | CPU which boots the operating system (usually CPU#0). | ||
6 | |||
7 | Linux supports all variants of compliant SMP boards, including ones with | ||
8 | multiple IO-APICs. Multiple IO-APICs are used in high-end servers to | ||
9 | distribute IRQ load further. | ||
10 | |||
11 | There are (a few) known breakages in certain older boards, such bugs are | ||
12 | usually worked around by the kernel. If your MP-compliant SMP board does | ||
13 | not boot Linux, then consult the linux-smp mailing list archives first. | ||
14 | |||
15 | If your box boots fine with enabled IO-APIC IRQs, then your | ||
16 | /proc/interrupts will look like this one: | ||
17 | |||
18 | ----------------------------> | ||
19 | hell:~> cat /proc/interrupts | ||
20 | CPU0 | ||
21 | 0: 1360293 IO-APIC-edge timer | ||
22 | 1: 4 IO-APIC-edge keyboard | ||
23 | 2: 0 XT-PIC cascade | ||
24 | 13: 1 XT-PIC fpu | ||
25 | 14: 1448 IO-APIC-edge ide0 | ||
26 | 16: 28232 IO-APIC-level Intel EtherExpress Pro 10/100 Ethernet | ||
27 | 17: 51304 IO-APIC-level eth0 | ||
28 | NMI: 0 | ||
29 | ERR: 0 | ||
30 | hell:~> | ||
31 | <---------------------------- | ||
32 | |||
33 | Some interrupts are still listed as 'XT PIC', but this is not a problem; | ||
34 | none of those IRQ sources is performance-critical. | ||
35 | |||
36 | |||
37 | In the unlikely case that your board does not create a working mp-table, | ||
38 | you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This | ||
39 | is non-trivial though and cannot be automated. One sample /etc/lilo.conf | ||
40 | entry: | ||
41 | |||
42 | append="pirq=15,11,10" | ||
43 | |||
44 | The actual numbers depend on your system, on your PCI cards and on their | ||
45 | PCI slot position. Usually PCI slots are 'daisy chained' before they are | ||
46 | connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4 | ||
47 | lines): | ||
48 | |||
49 | ,-. ,-. ,-. ,-. ,-. | ||
50 | PIRQ4 ----| |-. ,-| |-. ,-| |-. ,-| |--------| | | ||
51 | |S| \ / |S| \ / |S| \ / |S| |S| | ||
52 | PIRQ3 ----|l|-. `/---|l|-. `/---|l|-. `/---|l|--------|l| | ||
53 | |o| \/ |o| \/ |o| \/ |o| |o| | ||
54 | PIRQ2 ----|t|-./`----|t|-./`----|t|-./`----|t|--------|t| | ||
55 | |1| /\ |2| /\ |3| /\ |4| |5| | ||
56 | PIRQ1 ----| |- `----| |- `----| |- `----| |--------| | | ||
57 | `-' `-' `-' `-' `-' | ||
58 | |||
59 | Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD: | ||
60 | |||
61 | ,-. | ||
62 | INTD--| | | ||
63 | |S| | ||
64 | INTC--|l| | ||
65 | |o| | ||
66 | INTB--|t| | ||
67 | |x| | ||
68 | INTA--| | | ||
69 | `-' | ||
70 | |||
71 | These INTA-D PCI IRQs are always 'local to the card', their real meaning | ||
72 | depends on which slot they are in. If you look at the daisy chaining diagram, | ||
73 | a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ4 of | ||
74 | the PCI chipset. Most cards issue INTA, this creates optimal distribution | ||
75 | between the PIRQ lines. (distributing IRQ sources properly is not a | ||
76 | necessity, PCI IRQs can be shared at will, but it's a good for performance | ||
77 | to have non shared interrupts). Slot5 should be used for videocards, they | ||
78 | do not use interrupts normally, thus they are not daisy chained either. | ||
79 | |||
80 | so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in | ||
81 | Slot2, then you'll have to specify this pirq= line: | ||
82 | |||
83 | append="pirq=11,9" | ||
84 | |||
85 | the following script tries to figure out such a default pirq= line from | ||
86 | your PCI configuration: | ||
87 | |||
88 | echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g' | ||
89 | |||
90 | note that this script wont work if you have skipped a few slots or if your | ||
91 | board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins | ||
92 | connected in some strange way). E.g. if in the above case you have your SCSI | ||
93 | card (IRQ11) in Slot3, and have Slot1 empty: | ||
94 | |||
95 | append="pirq=0,9,11" | ||
96 | |||
97 | [value '0' is a generic 'placeholder', reserved for empty (or non-IRQ emitting) | ||
98 | slots.] | ||
99 | |||
100 | Generally, it's always possible to find out the correct pirq= settings, just | ||
101 | permute all IRQ numbers properly ... it will take some time though. An | ||
102 | 'incorrect' pirq line will cause the booting process to hang, or a device | ||
103 | won't function properly (e.g. if it's inserted as a module). | ||
104 | |||
105 | If you have 2 PCI buses, then you can use up to 8 pirq values, although such | ||
106 | boards tend to have a good configuration. | ||
107 | |||
108 | Be prepared that it might happen that you need some strange pirq line: | ||
109 | |||
110 | append="pirq=0,0,0,0,0,0,9,11" | ||
111 | |||
112 | Use smart trial-and-error techniques to find out the correct pirq line ... | ||
113 | |||
114 | Good luck and mail to linux-smp@vger.kernel.org or | ||
115 | linux-kernel@vger.kernel.org if you have any problems that are not covered | ||
116 | by this document. | ||
117 | |||
118 | -- mingo | ||
119 | |||
diff --git a/Documentation/x86/i386/boot.txt b/Documentation/x86/i386/boot.txt new file mode 100644 index 000000000000..147bfe511cdd --- /dev/null +++ b/Documentation/x86/i386/boot.txt | |||
@@ -0,0 +1,900 @@ | |||
1 | THE LINUX/x86 BOOT PROTOCOL | ||
2 | --------------------------- | ||
3 | |||
4 | On the x86 platform, the Linux kernel uses a rather complicated boot | ||
5 | convention. This has evolved partially due to historical aspects, as | ||
6 | well as the desire in the early days to have the kernel itself be a | ||
7 | bootable image, the complicated PC memory model and due to changed | ||
8 | expectations in the PC industry caused by the effective demise of | ||
9 | real-mode DOS as a mainstream operating system. | ||
10 | |||
11 | Currently, the following versions of the Linux/x86 boot protocol exist. | ||
12 | |||
13 | Old kernels: zImage/Image support only. Some very early kernels | ||
14 | may not even support a command line. | ||
15 | |||
16 | Protocol 2.00: (Kernel 1.3.73) Added bzImage and initrd support, as | ||
17 | well as a formalized way to communicate between the | ||
18 | boot loader and the kernel. setup.S made relocatable, | ||
19 | although the traditional setup area still assumed | ||
20 | writable. | ||
21 | |||
22 | Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning. | ||
23 | |||
24 | Protocol 2.02: (Kernel 2.4.0-test3-pre3) New command line protocol. | ||
25 | Lower the conventional memory ceiling. No overwrite | ||
26 | of the traditional setup area, thus making booting | ||
27 | safe for systems which use the EBDA from SMM or 32-bit | ||
28 | BIOS entry points. zImage deprecated but still | ||
29 | supported. | ||
30 | |||
31 | Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible | ||
32 | initrd address available to the bootloader. | ||
33 | |||
34 | Protocol 2.04: (Kernel 2.6.14) Extend the syssize field to four bytes. | ||
35 | |||
36 | Protocol 2.05: (Kernel 2.6.20) Make protected mode kernel relocatable. | ||
37 | Introduce relocatable_kernel and kernel_alignment fields. | ||
38 | |||
39 | Protocol 2.06: (Kernel 2.6.22) Added a field that contains the size of | ||
40 | the boot command line. | ||
41 | |||
42 | Protocol 2.07: (Kernel 2.6.24) Added paravirtualised boot protocol. | ||
43 | Introduced hardware_subarch and hardware_subarch_data | ||
44 | and KEEP_SEGMENTS flag in load_flags. | ||
45 | |||
46 | Protocol 2.08: (Kernel 2.6.26) Added crc32 checksum and ELF format | ||
47 | payload. Introduced payload_offset and payload length | ||
48 | fields to aid in locating the payload. | ||
49 | |||
50 | Protocol 2.09: (Kernel 2.6.26) Added a field of 64-bit physical | ||
51 | pointer to single linked list of struct setup_data. | ||
52 | |||
53 | **** MEMORY LAYOUT | ||
54 | |||
55 | The traditional memory map for the kernel loader, used for Image or | ||
56 | zImage kernels, typically looks like: | ||
57 | |||
58 | | | | ||
59 | 0A0000 +------------------------+ | ||
60 | | Reserved for BIOS | Do not use. Reserved for BIOS EBDA. | ||
61 | 09A000 +------------------------+ | ||
62 | | Command line | | ||
63 | | Stack/heap | For use by the kernel real-mode code. | ||
64 | 098000 +------------------------+ | ||
65 | | Kernel setup | The kernel real-mode code. | ||
66 | 090200 +------------------------+ | ||
67 | | Kernel boot sector | The kernel legacy boot sector. | ||
68 | 090000 +------------------------+ | ||
69 | | Protected-mode kernel | The bulk of the kernel image. | ||
70 | 010000 +------------------------+ | ||
71 | | Boot loader | <- Boot sector entry point 0000:7C00 | ||
72 | 001000 +------------------------+ | ||
73 | | Reserved for MBR/BIOS | | ||
74 | 000800 +------------------------+ | ||
75 | | Typically used by MBR | | ||
76 | 000600 +------------------------+ | ||
77 | | BIOS use only | | ||
78 | 000000 +------------------------+ | ||
79 | |||
80 | |||
81 | When using bzImage, the protected-mode kernel was relocated to | ||
82 | 0x100000 ("high memory"), and the kernel real-mode block (boot sector, | ||
83 | setup, and stack/heap) was made relocatable to any address between | ||
84 | 0x10000 and end of low memory. Unfortunately, in protocols 2.00 and | ||
85 | 2.01 the 0x90000+ memory range is still used internally by the kernel; | ||
86 | the 2.02 protocol resolves that problem. | ||
87 | |||
88 | It is desirable to keep the "memory ceiling" -- the highest point in | ||
89 | low memory touched by the boot loader -- as low as possible, since | ||
90 | some newer BIOSes have begun to allocate some rather large amounts of | ||
91 | memory, called the Extended BIOS Data Area, near the top of low | ||
92 | memory. The boot loader should use the "INT 12h" BIOS call to verify | ||
93 | how much low memory is available. | ||
94 | |||
95 | Unfortunately, if INT 12h reports that the amount of memory is too | ||
96 | low, there is usually nothing the boot loader can do but to report an | ||
97 | error to the user. The boot loader should therefore be designed to | ||
98 | take up as little space in low memory as it reasonably can. For | ||
99 | zImage or old bzImage kernels, which need data written into the | ||
100 | 0x90000 segment, the boot loader should make sure not to use memory | ||
101 | above the 0x9A000 point; too many BIOSes will break above that point. | ||
102 | |||
103 | For a modern bzImage kernel with boot protocol version >= 2.02, a | ||
104 | memory layout like the following is suggested: | ||
105 | |||
106 | ~ ~ | ||
107 | | Protected-mode kernel | | ||
108 | 100000 +------------------------+ | ||
109 | | I/O memory hole | | ||
110 | 0A0000 +------------------------+ | ||
111 | | Reserved for BIOS | Leave as much as possible unused | ||
112 | ~ ~ | ||
113 | | Command line | (Can also be below the X+10000 mark) | ||
114 | X+10000 +------------------------+ | ||
115 | | Stack/heap | For use by the kernel real-mode code. | ||
116 | X+08000 +------------------------+ | ||
117 | | Kernel setup | The kernel real-mode code. | ||
118 | | Kernel boot sector | The kernel legacy boot sector. | ||
119 | X +------------------------+ | ||
120 | | Boot loader | <- Boot sector entry point 0000:7C00 | ||
121 | 001000 +------------------------+ | ||
122 | | Reserved for MBR/BIOS | | ||
123 | 000800 +------------------------+ | ||
124 | | Typically used by MBR | | ||
125 | 000600 +------------------------+ | ||
126 | | BIOS use only | | ||
127 | 000000 +------------------------+ | ||
128 | |||
129 | ... where the address X is as low as the design of the boot loader | ||
130 | permits. | ||
131 | |||
132 | |||
133 | **** THE REAL-MODE KERNEL HEADER | ||
134 | |||
135 | In the following text, and anywhere in the kernel boot sequence, "a | ||
136 | sector" refers to 512 bytes. It is independent of the actual sector | ||
137 | size of the underlying medium. | ||
138 | |||
139 | The first step in loading a Linux kernel should be to load the | ||
140 | real-mode code (boot sector and setup code) and then examine the | ||
141 | following header at offset 0x01f1. The real-mode code can total up to | ||
142 | 32K, although the boot loader may choose to load only the first two | ||
143 | sectors (1K) and then examine the bootup sector size. | ||
144 | |||
145 | The header looks like: | ||
146 | |||
147 | Offset Proto Name Meaning | ||
148 | /Size | ||
149 | |||
150 | 01F1/1 ALL(1 setup_sects The size of the setup in sectors | ||
151 | 01F2/2 ALL root_flags If set, the root is mounted readonly | ||
152 | 01F4/4 2.04+(2 syssize The size of the 32-bit code in 16-byte paras | ||
153 | 01F8/2 ALL ram_size DO NOT USE - for bootsect.S use only | ||
154 | 01FA/2 ALL vid_mode Video mode control | ||
155 | 01FC/2 ALL root_dev Default root device number | ||
156 | 01FE/2 ALL boot_flag 0xAA55 magic number | ||
157 | 0200/2 2.00+ jump Jump instruction | ||
158 | 0202/4 2.00+ header Magic signature "HdrS" | ||
159 | 0206/2 2.00+ version Boot protocol version supported | ||
160 | 0208/4 2.00+ realmode_swtch Boot loader hook (see below) | ||
161 | 020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete) | ||
162 | 020E/2 2.00+ kernel_version Pointer to kernel version string | ||
163 | 0210/1 2.00+ type_of_loader Boot loader identifier | ||
164 | 0211/1 2.00+ loadflags Boot protocol option flags | ||
165 | 0212/2 2.00+ setup_move_size Move to high memory size (used with hooks) | ||
166 | 0214/4 2.00+ code32_start Boot loader hook (see below) | ||
167 | 0218/4 2.00+ ramdisk_image initrd load address (set by boot loader) | ||
168 | 021C/4 2.00+ ramdisk_size initrd size (set by boot loader) | ||
169 | 0220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only | ||
170 | 0224/2 2.01+ heap_end_ptr Free memory after setup end | ||
171 | 0226/2 N/A pad1 Unused | ||
172 | 0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line | ||
173 | 022C/4 2.03+ initrd_addr_max Highest legal initrd address | ||
174 | 0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel | ||
175 | 0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not | ||
176 | 0235/3 N/A pad2 Unused | ||
177 | 0238/4 2.06+ cmdline_size Maximum size of the kernel command line | ||
178 | 023C/4 2.07+ hardware_subarch Hardware subarchitecture | ||
179 | 0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data | ||
180 | 0248/4 2.08+ payload_offset Offset of kernel payload | ||
181 | 024C/4 2.08+ payload_length Length of kernel payload | ||
182 | 0250/8 2.09+ setup_data 64-bit physical pointer to linked list | ||
183 | of struct setup_data | ||
184 | |||
185 | (1) For backwards compatibility, if the setup_sects field contains 0, the | ||
186 | real value is 4. | ||
187 | |||
188 | (2) For boot protocol prior to 2.04, the upper two bytes of the syssize | ||
189 | field are unusable, which means the size of a bzImage kernel | ||
190 | cannot be determined. | ||
191 | |||
192 | If the "HdrS" (0x53726448) magic number is not found at offset 0x202, | ||
193 | the boot protocol version is "old". Loading an old kernel, the | ||
194 | following parameters should be assumed: | ||
195 | |||
196 | Image type = zImage | ||
197 | initrd not supported | ||
198 | Real-mode kernel must be located at 0x90000. | ||
199 | |||
200 | Otherwise, the "version" field contains the protocol version, | ||
201 | e.g. protocol version 2.01 will contain 0x0201 in this field. When | ||
202 | setting fields in the header, you must make sure only to set fields | ||
203 | supported by the protocol version in use. | ||
204 | |||
205 | |||
206 | **** DETAILS OF HEADER FIELDS | ||
207 | |||
208 | For each field, some are information from the kernel to the bootloader | ||
209 | ("read"), some are expected to be filled out by the bootloader | ||
210 | ("write"), and some are expected to be read and modified by the | ||
211 | bootloader ("modify"). | ||
212 | |||
213 | All general purpose boot loaders should write the fields marked | ||
214 | (obligatory). Boot loaders who want to load the kernel at a | ||
215 | nonstandard address should fill in the fields marked (reloc); other | ||
216 | boot loaders can ignore those fields. | ||
217 | |||
218 | The byte order of all fields is littleendian (this is x86, after all.) | ||
219 | |||
220 | Field name: setup_sects | ||
221 | Type: read | ||
222 | Offset/size: 0x1f1/1 | ||
223 | Protocol: ALL | ||
224 | |||
225 | The size of the setup code in 512-byte sectors. If this field is | ||
226 | 0, the real value is 4. The real-mode code consists of the boot | ||
227 | sector (always one 512-byte sector) plus the setup code. | ||
228 | |||
229 | Field name: root_flags | ||
230 | Type: modify (optional) | ||
231 | Offset/size: 0x1f2/2 | ||
232 | Protocol: ALL | ||
233 | |||
234 | If this field is nonzero, the root defaults to readonly. The use of | ||
235 | this field is deprecated; use the "ro" or "rw" options on the | ||
236 | command line instead. | ||
237 | |||
238 | Field name: syssize | ||
239 | Type: read | ||
240 | Offset/size: 0x1f4/4 (protocol 2.04+) 0x1f4/2 (protocol ALL) | ||
241 | Protocol: 2.04+ | ||
242 | |||
243 | The size of the protected-mode code in units of 16-byte paragraphs. | ||
244 | For protocol versions older than 2.04 this field is only two bytes | ||
245 | wide, and therefore cannot be trusted for the size of a kernel if | ||
246 | the LOAD_HIGH flag is set. | ||
247 | |||
248 | Field name: ram_size | ||
249 | Type: kernel internal | ||
250 | Offset/size: 0x1f8/2 | ||
251 | Protocol: ALL | ||
252 | |||
253 | This field is obsolete. | ||
254 | |||
255 | Field name: vid_mode | ||
256 | Type: modify (obligatory) | ||
257 | Offset/size: 0x1fa/2 | ||
258 | |||
259 | Please see the section on SPECIAL COMMAND LINE OPTIONS. | ||
260 | |||
261 | Field name: root_dev | ||
262 | Type: modify (optional) | ||
263 | Offset/size: 0x1fc/2 | ||
264 | Protocol: ALL | ||
265 | |||
266 | The default root device device number. The use of this field is | ||
267 | deprecated, use the "root=" option on the command line instead. | ||
268 | |||
269 | Field name: boot_flag | ||
270 | Type: read | ||
271 | Offset/size: 0x1fe/2 | ||
272 | Protocol: ALL | ||
273 | |||
274 | Contains 0xAA55. This is the closest thing old Linux kernels have | ||
275 | to a magic number. | ||
276 | |||
277 | Field name: jump | ||
278 | Type: read | ||
279 | Offset/size: 0x200/2 | ||
280 | Protocol: 2.00+ | ||
281 | |||
282 | Contains an x86 jump instruction, 0xEB followed by a signed offset | ||
283 | relative to byte 0x202. This can be used to determine the size of | ||
284 | the header. | ||
285 | |||
286 | Field name: header | ||
287 | Type: read | ||
288 | Offset/size: 0x202/4 | ||
289 | Protocol: 2.00+ | ||
290 | |||
291 | Contains the magic number "HdrS" (0x53726448). | ||
292 | |||
293 | Field name: version | ||
294 | Type: read | ||
295 | Offset/size: 0x206/2 | ||
296 | Protocol: 2.00+ | ||
297 | |||
298 | Contains the boot protocol version, in (major << 8)+minor format, | ||
299 | e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version | ||
300 | 10.17. | ||
301 | |||
302 | Field name: readmode_swtch | ||
303 | Type: modify (optional) | ||
304 | Offset/size: 0x208/4 | ||
305 | Protocol: 2.00+ | ||
306 | |||
307 | Boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) | ||
308 | |||
309 | Field name: start_sys | ||
310 | Type: read | ||
311 | Offset/size: 0x20c/4 | ||
312 | Protocol: 2.00+ | ||
313 | |||
314 | The load low segment (0x1000). Obsolete. | ||
315 | |||
316 | Field name: kernel_version | ||
317 | Type: read | ||
318 | Offset/size: 0x20e/2 | ||
319 | Protocol: 2.00+ | ||
320 | |||
321 | If set to a nonzero value, contains a pointer to a NUL-terminated | ||
322 | human-readable kernel version number string, less 0x200. This can | ||
323 | be used to display the kernel version to the user. This value | ||
324 | should be less than (0x200*setup_sects). | ||
325 | |||
326 | For example, if this value is set to 0x1c00, the kernel version | ||
327 | number string can be found at offset 0x1e00 in the kernel file. | ||
328 | This is a valid value if and only if the "setup_sects" field | ||
329 | contains the value 15 or higher, as: | ||
330 | |||
331 | 0x1c00 < 15*0x200 (= 0x1e00) but | ||
332 | 0x1c00 >= 14*0x200 (= 0x1c00) | ||
333 | |||
334 | 0x1c00 >> 9 = 14, so the minimum value for setup_secs is 15. | ||
335 | |||
336 | Field name: type_of_loader | ||
337 | Type: write (obligatory) | ||
338 | Offset/size: 0x210/1 | ||
339 | Protocol: 2.00+ | ||
340 | |||
341 | If your boot loader has an assigned id (see table below), enter | ||
342 | 0xTV here, where T is an identifier for the boot loader and V is | ||
343 | a version number. Otherwise, enter 0xFF here. | ||
344 | |||
345 | Assigned boot loader ids: | ||
346 | 0 LILO (0x00 reserved for pre-2.00 bootloader) | ||
347 | 1 Loadlin | ||
348 | 2 bootsect-loader (0x20, all other values reserved) | ||
349 | 3 SYSLINUX | ||
350 | 4 EtherBoot | ||
351 | 5 ELILO | ||
352 | 7 GRuB | ||
353 | 8 U-BOOT | ||
354 | 9 Xen | ||
355 | A Gujin | ||
356 | B Qemu | ||
357 | |||
358 | Please contact <hpa@zytor.com> if you need a bootloader ID | ||
359 | value assigned. | ||
360 | |||
361 | Field name: loadflags | ||
362 | Type: modify (obligatory) | ||
363 | Offset/size: 0x211/1 | ||
364 | Protocol: 2.00+ | ||
365 | |||
366 | This field is a bitmask. | ||
367 | |||
368 | Bit 0 (read): LOADED_HIGH | ||
369 | - If 0, the protected-mode code is loaded at 0x10000. | ||
370 | - If 1, the protected-mode code is loaded at 0x100000. | ||
371 | |||
372 | Bit 5 (write): QUIET_FLAG | ||
373 | - If 0, print early messages. | ||
374 | - If 1, suppress early messages. | ||
375 | This requests to the kernel (decompressor and early | ||
376 | kernel) to not write early messages that require | ||
377 | accessing the display hardware directly. | ||
378 | |||
379 | Bit 6 (write): KEEP_SEGMENTS | ||
380 | Protocol: 2.07+ | ||
381 | - If 0, reload the segment registers in the 32bit entry point. | ||
382 | - If 1, do not reload the segment registers in the 32bit entry point. | ||
383 | Assume that %cs %ds %ss %es are all set to flat segments with | ||
384 | a base of 0 (or the equivalent for their environment). | ||
385 | |||
386 | Bit 7 (write): CAN_USE_HEAP | ||
387 | Set this bit to 1 to indicate that the value entered in the | ||
388 | heap_end_ptr is valid. If this field is clear, some setup code | ||
389 | functionality will be disabled. | ||
390 | |||
391 | Field name: setup_move_size | ||
392 | Type: modify (obligatory) | ||
393 | Offset/size: 0x212/2 | ||
394 | Protocol: 2.00-2.01 | ||
395 | |||
396 | When using protocol 2.00 or 2.01, if the real mode kernel is not | ||
397 | loaded at 0x90000, it gets moved there later in the loading | ||
398 | sequence. Fill in this field if you want additional data (such as | ||
399 | the kernel command line) moved in addition to the real-mode kernel | ||
400 | itself. | ||
401 | |||
402 | The unit is bytes starting with the beginning of the boot sector. | ||
403 | |||
404 | This field is can be ignored when the protocol is 2.02 or higher, or | ||
405 | if the real-mode code is loaded at 0x90000. | ||
406 | |||
407 | Field name: code32_start | ||
408 | Type: modify (optional, reloc) | ||
409 | Offset/size: 0x214/4 | ||
410 | Protocol: 2.00+ | ||
411 | |||
412 | The address to jump to in protected mode. This defaults to the load | ||
413 | address of the kernel, and can be used by the boot loader to | ||
414 | determine the proper load address. | ||
415 | |||
416 | This field can be modified for two purposes: | ||
417 | |||
418 | 1. as a boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) | ||
419 | |||
420 | 2. if a bootloader which does not install a hook loads a | ||
421 | relocatable kernel at a nonstandard address it will have to modify | ||
422 | this field to point to the load address. | ||
423 | |||
424 | Field name: ramdisk_image | ||
425 | Type: write (obligatory) | ||
426 | Offset/size: 0x218/4 | ||
427 | Protocol: 2.00+ | ||
428 | |||
429 | The 32-bit linear address of the initial ramdisk or ramfs. Leave at | ||
430 | zero if there is no initial ramdisk/ramfs. | ||
431 | |||
432 | Field name: ramdisk_size | ||
433 | Type: write (obligatory) | ||
434 | Offset/size: 0x21c/4 | ||
435 | Protocol: 2.00+ | ||
436 | |||
437 | Size of the initial ramdisk or ramfs. Leave at zero if there is no | ||
438 | initial ramdisk/ramfs. | ||
439 | |||
440 | Field name: bootsect_kludge | ||
441 | Type: kernel internal | ||
442 | Offset/size: 0x220/4 | ||
443 | Protocol: 2.00+ | ||
444 | |||
445 | This field is obsolete. | ||
446 | |||
447 | Field name: heap_end_ptr | ||
448 | Type: write (obligatory) | ||
449 | Offset/size: 0x224/2 | ||
450 | Protocol: 2.01+ | ||
451 | |||
452 | Set this field to the offset (from the beginning of the real-mode | ||
453 | code) of the end of the setup stack/heap, minus 0x0200. | ||
454 | |||
455 | Field name: cmd_line_ptr | ||
456 | Type: write (obligatory) | ||
457 | Offset/size: 0x228/4 | ||
458 | Protocol: 2.02+ | ||
459 | |||
460 | Set this field to the linear address of the kernel command line. | ||
461 | The kernel command line can be located anywhere between the end of | ||
462 | the setup heap and 0xA0000; it does not have to be located in the | ||
463 | same 64K segment as the real-mode code itself. | ||
464 | |||
465 | Fill in this field even if your boot loader does not support a | ||
466 | command line, in which case you can point this to an empty string | ||
467 | (or better yet, to the string "auto".) If this field is left at | ||
468 | zero, the kernel will assume that your boot loader does not support | ||
469 | the 2.02+ protocol. | ||
470 | |||
471 | Field name: initrd_addr_max | ||
472 | Type: read | ||
473 | Offset/size: 0x22c/4 | ||
474 | Protocol: 2.03+ | ||
475 | |||
476 | The maximum address that may be occupied by the initial | ||
477 | ramdisk/ramfs contents. For boot protocols 2.02 or earlier, this | ||
478 | field is not present, and the maximum address is 0x37FFFFFF. (This | ||
479 | address is defined as the address of the highest safe byte, so if | ||
480 | your ramdisk is exactly 131072 bytes long and this field is | ||
481 | 0x37FFFFFF, you can start your ramdisk at 0x37FE0000.) | ||
482 | |||
483 | Field name: kernel_alignment | ||
484 | Type: read (reloc) | ||
485 | Offset/size: 0x230/4 | ||
486 | Protocol: 2.05+ | ||
487 | |||
488 | Alignment unit required by the kernel (if relocatable_kernel is true.) | ||
489 | |||
490 | Field name: relocatable_kernel | ||
491 | Type: read (reloc) | ||
492 | Offset/size: 0x234/1 | ||
493 | Protocol: 2.05+ | ||
494 | |||
495 | If this field is nonzero, the protected-mode part of the kernel can | ||
496 | be loaded at any address that satisfies the kernel_alignment field. | ||
497 | After loading, the boot loader must set the code32_start field to | ||
498 | point to the loaded code, or to a boot loader hook. | ||
499 | |||
500 | Field name: cmdline_size | ||
501 | Type: read | ||
502 | Offset/size: 0x238/4 | ||
503 | Protocol: 2.06+ | ||
504 | |||
505 | The maximum size of the command line without the terminating | ||
506 | zero. This means that the command line can contain at most | ||
507 | cmdline_size characters. With protocol version 2.05 and earlier, the | ||
508 | maximum size was 255. | ||
509 | |||
510 | Field name: hardware_subarch | ||
511 | Type: write (optional, defaults to x86/PC) | ||
512 | Offset/size: 0x23c/4 | ||
513 | Protocol: 2.07+ | ||
514 | |||
515 | In a paravirtualized environment the hardware low level architectural | ||
516 | pieces such as interrupt handling, page table handling, and | ||
517 | accessing process control registers needs to be done differently. | ||
518 | |||
519 | This field allows the bootloader to inform the kernel we are in one | ||
520 | one of those environments. | ||
521 | |||
522 | 0x00000000 The default x86/PC environment | ||
523 | 0x00000001 lguest | ||
524 | 0x00000002 Xen | ||
525 | |||
526 | Field name: hardware_subarch_data | ||
527 | Type: write (subarch-dependent) | ||
528 | Offset/size: 0x240/8 | ||
529 | Protocol: 2.07+ | ||
530 | |||
531 | A pointer to data that is specific to hardware subarch | ||
532 | This field is currently unused for the default x86/PC environment, | ||
533 | do not modify. | ||
534 | |||
535 | Field name: payload_offset | ||
536 | Type: read | ||
537 | Offset/size: 0x248/4 | ||
538 | Protocol: 2.08+ | ||
539 | |||
540 | If non-zero then this field contains the offset from the end of the | ||
541 | real-mode code to the payload. | ||
542 | |||
543 | The payload may be compressed. The format of both the compressed and | ||
544 | uncompressed data should be determined using the standard magic | ||
545 | numbers. Currently only gzip compressed ELF is used. | ||
546 | |||
547 | Field name: payload_length | ||
548 | Type: read | ||
549 | Offset/size: 0x24c/4 | ||
550 | Protocol: 2.08+ | ||
551 | |||
552 | The length of the payload. | ||
553 | |||
554 | Field name: setup_data | ||
555 | Type: write (special) | ||
556 | Offset/size: 0x250/8 | ||
557 | Protocol: 2.09+ | ||
558 | |||
559 | The 64-bit physical pointer to NULL terminated single linked list of | ||
560 | struct setup_data. This is used to define a more extensible boot | ||
561 | parameters passing mechanism. The definition of struct setup_data is | ||
562 | as follow: | ||
563 | |||
564 | struct setup_data { | ||
565 | u64 next; | ||
566 | u32 type; | ||
567 | u32 len; | ||
568 | u8 data[0]; | ||
569 | }; | ||
570 | |||
571 | Where, the next is a 64-bit physical pointer to the next node of | ||
572 | linked list, the next field of the last node is 0; the type is used | ||
573 | to identify the contents of data; the len is the length of data | ||
574 | field; the data holds the real payload. | ||
575 | |||
576 | This list may be modified at a number of points during the bootup | ||
577 | process. Therefore, when modifying this list one should always make | ||
578 | sure to consider the case where the linked list already contains | ||
579 | entries. | ||
580 | |||
581 | |||
582 | **** THE IMAGE CHECKSUM | ||
583 | |||
584 | From boot protocol version 2.08 onwards the CRC-32 is calculated over | ||
585 | the entire file using the characteristic polynomial 0x04C11DB7 and an | ||
586 | initial remainder of 0xffffffff. The checksum is appended to the | ||
587 | file; therefore the CRC of the file up to the limit specified in the | ||
588 | syssize field of the header is always 0. | ||
589 | |||
590 | |||
591 | **** THE KERNEL COMMAND LINE | ||
592 | |||
593 | The kernel command line has become an important way for the boot | ||
594 | loader to communicate with the kernel. Some of its options are also | ||
595 | relevant to the boot loader itself, see "special command line options" | ||
596 | below. | ||
597 | |||
598 | The kernel command line is a null-terminated string. The maximum | ||
599 | length can be retrieved from the field cmdline_size. Before protocol | ||
600 | version 2.06, the maximum was 255 characters. A string that is too | ||
601 | long will be automatically truncated by the kernel. | ||
602 | |||
603 | If the boot protocol version is 2.02 or later, the address of the | ||
604 | kernel command line is given by the header field cmd_line_ptr (see | ||
605 | above.) This address can be anywhere between the end of the setup | ||
606 | heap and 0xA0000. | ||
607 | |||
608 | If the protocol version is *not* 2.02 or higher, the kernel | ||
609 | command line is entered using the following protocol: | ||
610 | |||
611 | At offset 0x0020 (word), "cmd_line_magic", enter the magic | ||
612 | number 0xA33F. | ||
613 | |||
614 | At offset 0x0022 (word), "cmd_line_offset", enter the offset | ||
615 | of the kernel command line (relative to the start of the | ||
616 | real-mode kernel). | ||
617 | |||
618 | The kernel command line *must* be within the memory region | ||
619 | covered by setup_move_size, so you may need to adjust this | ||
620 | field. | ||
621 | |||
622 | |||
623 | **** MEMORY LAYOUT OF THE REAL-MODE CODE | ||
624 | |||
625 | The real-mode code requires a stack/heap to be set up, as well as | ||
626 | memory allocated for the kernel command line. This needs to be done | ||
627 | in the real-mode accessible memory in bottom megabyte. | ||
628 | |||
629 | It should be noted that modern machines often have a sizable Extended | ||
630 | BIOS Data Area (EBDA). As a result, it is advisable to use as little | ||
631 | of the low megabyte as possible. | ||
632 | |||
633 | Unfortunately, under the following circumstances the 0x90000 memory | ||
634 | segment has to be used: | ||
635 | |||
636 | - When loading a zImage kernel ((loadflags & 0x01) == 0). | ||
637 | - When loading a 2.01 or earlier boot protocol kernel. | ||
638 | |||
639 | -> For the 2.00 and 2.01 boot protocols, the real-mode code | ||
640 | can be loaded at another address, but it is internally | ||
641 | relocated to 0x90000. For the "old" protocol, the | ||
642 | real-mode code must be loaded at 0x90000. | ||
643 | |||
644 | When loading at 0x90000, avoid using memory above 0x9a000. | ||
645 | |||
646 | For boot protocol 2.02 or higher, the command line does not have to be | ||
647 | located in the same 64K segment as the real-mode setup code; it is | ||
648 | thus permitted to give the stack/heap the full 64K segment and locate | ||
649 | the command line above it. | ||
650 | |||
651 | The kernel command line should not be located below the real-mode | ||
652 | code, nor should it be located in high memory. | ||
653 | |||
654 | |||
655 | **** SAMPLE BOOT CONFIGURATION | ||
656 | |||
657 | As a sample configuration, assume the following layout of the real | ||
658 | mode segment: | ||
659 | |||
660 | When loading below 0x90000, use the entire segment: | ||
661 | |||
662 | 0x0000-0x7fff Real mode kernel | ||
663 | 0x8000-0xdfff Stack and heap | ||
664 | 0xe000-0xffff Kernel command line | ||
665 | |||
666 | When loading at 0x90000 OR the protocol version is 2.01 or earlier: | ||
667 | |||
668 | 0x0000-0x7fff Real mode kernel | ||
669 | 0x8000-0x97ff Stack and heap | ||
670 | 0x9800-0x9fff Kernel command line | ||
671 | |||
672 | Such a boot loader should enter the following fields in the header: | ||
673 | |||
674 | unsigned long base_ptr; /* base address for real-mode segment */ | ||
675 | |||
676 | if ( setup_sects == 0 ) { | ||
677 | setup_sects = 4; | ||
678 | } | ||
679 | |||
680 | if ( protocol >= 0x0200 ) { | ||
681 | type_of_loader = <type code>; | ||
682 | if ( loading_initrd ) { | ||
683 | ramdisk_image = <initrd_address>; | ||
684 | ramdisk_size = <initrd_size>; | ||
685 | } | ||
686 | |||
687 | if ( protocol >= 0x0202 && loadflags & 0x01 ) | ||
688 | heap_end = 0xe000; | ||
689 | else | ||
690 | heap_end = 0x9800; | ||
691 | |||
692 | if ( protocol >= 0x0201 ) { | ||
693 | heap_end_ptr = heap_end - 0x200; | ||
694 | loadflags |= 0x80; /* CAN_USE_HEAP */ | ||
695 | } | ||
696 | |||
697 | if ( protocol >= 0x0202 ) { | ||
698 | cmd_line_ptr = base_ptr + heap_end; | ||
699 | strcpy(cmd_line_ptr, cmdline); | ||
700 | } else { | ||
701 | cmd_line_magic = 0xA33F; | ||
702 | cmd_line_offset = heap_end; | ||
703 | setup_move_size = heap_end + strlen(cmdline)+1; | ||
704 | strcpy(base_ptr+cmd_line_offset, cmdline); | ||
705 | } | ||
706 | } else { | ||
707 | /* Very old kernel */ | ||
708 | |||
709 | heap_end = 0x9800; | ||
710 | |||
711 | cmd_line_magic = 0xA33F; | ||
712 | cmd_line_offset = heap_end; | ||
713 | |||
714 | /* A very old kernel MUST have its real-mode code | ||
715 | loaded at 0x90000 */ | ||
716 | |||
717 | if ( base_ptr != 0x90000 ) { | ||
718 | /* Copy the real-mode kernel */ | ||
719 | memcpy(0x90000, base_ptr, (setup_sects+1)*512); | ||
720 | base_ptr = 0x90000; /* Relocated */ | ||
721 | } | ||
722 | |||
723 | strcpy(0x90000+cmd_line_offset, cmdline); | ||
724 | |||
725 | /* It is recommended to clear memory up to the 32K mark */ | ||
726 | memset(0x90000 + (setup_sects+1)*512, 0, | ||
727 | (64-(setup_sects+1))*512); | ||
728 | } | ||
729 | |||
730 | |||
731 | **** LOADING THE REST OF THE KERNEL | ||
732 | |||
733 | The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512 | ||
734 | in the kernel file (again, if setup_sects == 0 the real value is 4.) | ||
735 | It should be loaded at address 0x10000 for Image/zImage kernels and | ||
736 | 0x100000 for bzImage kernels. | ||
737 | |||
738 | The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01 | ||
739 | bit (LOAD_HIGH) in the loadflags field is set: | ||
740 | |||
741 | is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01); | ||
742 | load_address = is_bzImage ? 0x100000 : 0x10000; | ||
743 | |||
744 | Note that Image/zImage kernels can be up to 512K in size, and thus use | ||
745 | the entire 0x10000-0x90000 range of memory. This means it is pretty | ||
746 | much a requirement for these kernels to load the real-mode part at | ||
747 | 0x90000. bzImage kernels allow much more flexibility. | ||
748 | |||
749 | |||
750 | **** SPECIAL COMMAND LINE OPTIONS | ||
751 | |||
752 | If the command line provided by the boot loader is entered by the | ||
753 | user, the user may expect the following command line options to work. | ||
754 | They should normally not be deleted from the kernel command line even | ||
755 | though not all of them are actually meaningful to the kernel. Boot | ||
756 | loader authors who need additional command line options for the boot | ||
757 | loader itself should get them registered in | ||
758 | Documentation/kernel-parameters.txt to make sure they will not | ||
759 | conflict with actual kernel options now or in the future. | ||
760 | |||
761 | vga=<mode> | ||
762 | <mode> here is either an integer (in C notation, either | ||
763 | decimal, octal, or hexadecimal) or one of the strings | ||
764 | "normal" (meaning 0xFFFF), "ext" (meaning 0xFFFE) or "ask" | ||
765 | (meaning 0xFFFD). This value should be entered into the | ||
766 | vid_mode field, as it is used by the kernel before the command | ||
767 | line is parsed. | ||
768 | |||
769 | mem=<size> | ||
770 | <size> is an integer in C notation optionally followed by | ||
771 | (case insensitive) K, M, G, T, P or E (meaning << 10, << 20, | ||
772 | << 30, << 40, << 50 or << 60). This specifies the end of | ||
773 | memory to the kernel. This affects the possible placement of | ||
774 | an initrd, since an initrd should be placed near end of | ||
775 | memory. Note that this is an option to *both* the kernel and | ||
776 | the bootloader! | ||
777 | |||
778 | initrd=<file> | ||
779 | An initrd should be loaded. The meaning of <file> is | ||
780 | obviously bootloader-dependent, and some boot loaders | ||
781 | (e.g. LILO) do not have such a command. | ||
782 | |||
783 | In addition, some boot loaders add the following options to the | ||
784 | user-specified command line: | ||
785 | |||
786 | BOOT_IMAGE=<file> | ||
787 | The boot image which was loaded. Again, the meaning of <file> | ||
788 | is obviously bootloader-dependent. | ||
789 | |||
790 | auto | ||
791 | The kernel was booted without explicit user intervention. | ||
792 | |||
793 | If these options are added by the boot loader, it is highly | ||
794 | recommended that they are located *first*, before the user-specified | ||
795 | or configuration-specified command line. Otherwise, "init=/bin/sh" | ||
796 | gets confused by the "auto" option. | ||
797 | |||
798 | |||
799 | **** RUNNING THE KERNEL | ||
800 | |||
801 | The kernel is started by jumping to the kernel entry point, which is | ||
802 | located at *segment* offset 0x20 from the start of the real mode | ||
803 | kernel. This means that if you loaded your real-mode kernel code at | ||
804 | 0x90000, the kernel entry point is 9020:0000. | ||
805 | |||
806 | At entry, ds = es = ss should point to the start of the real-mode | ||
807 | kernel code (0x9000 if the code is loaded at 0x90000), sp should be | ||
808 | set up properly, normally pointing to the top of the heap, and | ||
809 | interrupts should be disabled. Furthermore, to guard against bugs in | ||
810 | the kernel, it is recommended that the boot loader sets fs = gs = ds = | ||
811 | es = ss. | ||
812 | |||
813 | In our example from above, we would do: | ||
814 | |||
815 | /* Note: in the case of the "old" kernel protocol, base_ptr must | ||
816 | be == 0x90000 at this point; see the previous sample code */ | ||
817 | |||
818 | seg = base_ptr >> 4; | ||
819 | |||
820 | cli(); /* Enter with interrupts disabled! */ | ||
821 | |||
822 | /* Set up the real-mode kernel stack */ | ||
823 | _SS = seg; | ||
824 | _SP = heap_end; | ||
825 | |||
826 | _DS = _ES = _FS = _GS = seg; | ||
827 | jmp_far(seg+0x20, 0); /* Run the kernel */ | ||
828 | |||
829 | If your boot sector accesses a floppy drive, it is recommended to | ||
830 | switch off the floppy motor before running the kernel, since the | ||
831 | kernel boot leaves interrupts off and thus the motor will not be | ||
832 | switched off, especially if the loaded kernel has the floppy driver as | ||
833 | a demand-loaded module! | ||
834 | |||
835 | |||
836 | **** ADVANCED BOOT LOADER HOOKS | ||
837 | |||
838 | If the boot loader runs in a particularly hostile environment (such as | ||
839 | LOADLIN, which runs under DOS) it may be impossible to follow the | ||
840 | standard memory location requirements. Such a boot loader may use the | ||
841 | following hooks that, if set, are invoked by the kernel at the | ||
842 | appropriate time. The use of these hooks should probably be | ||
843 | considered an absolutely last resort! | ||
844 | |||
845 | IMPORTANT: All the hooks are required to preserve %esp, %ebp, %esi and | ||
846 | %edi across invocation. | ||
847 | |||
848 | realmode_swtch: | ||
849 | A 16-bit real mode far subroutine invoked immediately before | ||
850 | entering protected mode. The default routine disables NMI, so | ||
851 | your routine should probably do so, too. | ||
852 | |||
853 | code32_start: | ||
854 | A 32-bit flat-mode routine *jumped* to immediately after the | ||
855 | transition to protected mode, but before the kernel is | ||
856 | uncompressed. No segments, except CS, are guaranteed to be | ||
857 | set up (current kernels do, but older ones do not); you should | ||
858 | set them up to BOOT_DS (0x18) yourself. | ||
859 | |||
860 | After completing your hook, you should jump to the address | ||
861 | that was in this field before your boot loader overwrote it | ||
862 | (relocated, if appropriate.) | ||
863 | |||
864 | |||
865 | **** 32-bit BOOT PROTOCOL | ||
866 | |||
867 | For machine with some new BIOS other than legacy BIOS, such as EFI, | ||
868 | LinuxBIOS, etc, and kexec, the 16-bit real mode setup code in kernel | ||
869 | based on legacy BIOS can not be used, so a 32-bit boot protocol needs | ||
870 | to be defined. | ||
871 | |||
872 | In 32-bit boot protocol, the first step in loading a Linux kernel | ||
873 | should be to setup the boot parameters (struct boot_params, | ||
874 | traditionally known as "zero page"). The memory for struct boot_params | ||
875 | should be allocated and initialized to all zero. Then the setup header | ||
876 | from offset 0x01f1 of kernel image on should be loaded into struct | ||
877 | boot_params and examined. The end of setup header can be calculated as | ||
878 | follow: | ||
879 | |||
880 | 0x0202 + byte value at offset 0x0201 | ||
881 | |||
882 | In addition to read/modify/write the setup header of the struct | ||
883 | boot_params as that of 16-bit boot protocol, the boot loader should | ||
884 | also fill the additional fields of the struct boot_params as that | ||
885 | described in zero-page.txt. | ||
886 | |||
887 | After setupping the struct boot_params, the boot loader can load the | ||
888 | 32/64-bit kernel in the same way as that of 16-bit boot protocol. | ||
889 | |||
890 | In 32-bit boot protocol, the kernel is started by jumping to the | ||
891 | 32-bit kernel entry point, which is the start address of loaded | ||
892 | 32/64-bit kernel. | ||
893 | |||
894 | At entry, the CPU must be in 32-bit protected mode with paging | ||
895 | disabled; a GDT must be loaded with the descriptors for selectors | ||
896 | __BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat | ||
897 | segment; __BOOS_CS must have execute/read permission, and __BOOT_DS | ||
898 | must have read/write permission; CS must be __BOOT_CS and DS, ES, SS | ||
899 | must be __BOOT_DS; interrupt must be disabled; %esi must hold the base | ||
900 | address of the struct boot_params; %ebp, %edi and %ebx must be zero. | ||
diff --git a/Documentation/x86/i386/usb-legacy-support.txt b/Documentation/x86/i386/usb-legacy-support.txt new file mode 100644 index 000000000000..1894cdfc69d9 --- /dev/null +++ b/Documentation/x86/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/x86/i386/zero-page.txt b/Documentation/x86/i386/zero-page.txt new file mode 100644 index 000000000000..169ad423a3d1 --- /dev/null +++ b/Documentation/x86/i386/zero-page.txt | |||
@@ -0,0 +1,31 @@ | |||
1 | The additional fields in struct boot_params as a part of 32-bit boot | ||
2 | protocol of kernel. These should be filled by bootloader or 16-bit | ||
3 | real-mode setup code of the kernel. References/settings to it mainly | ||
4 | are in: | ||
5 | |||
6 | include/asm-x86/bootparam.h | ||
7 | |||
8 | |||
9 | Offset Proto Name Meaning | ||
10 | /Size | ||
11 | |||
12 | 000/040 ALL screen_info Text mode or frame buffer information | ||
13 | (struct screen_info) | ||
14 | 040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) | ||
15 | 060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information | ||
16 | (struct ist_info) | ||
17 | 080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! | ||
18 | 090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!! | ||
19 | 0A0/010 ALL sys_desc_table System description table (struct sys_desc_table) | ||
20 | 140/080 ALL edid_info Video mode setup (struct edid_info) | ||
21 | 1C0/020 ALL efi_info EFI 32 information (struct efi_info) | ||
22 | 1E0/004 ALL alk_mem_k Alternative mem check, in KB | ||
23 | 1E4/004 ALL scratch Scratch field for the kernel setup code | ||
24 | 1E8/001 ALL e820_entries Number of entries in e820_map (below) | ||
25 | 1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below) | ||
26 | 1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer | ||
27 | (below) | ||
28 | 290/040 ALL edd_mbr_sig_buffer EDD MBR signatures | ||
29 | 2D0/A00 ALL e820_map E820 memory map table | ||
30 | (array of struct e820entry) | ||
31 | D00/1EC ALL eddbuf EDD data (array of struct edd_info) | ||
diff --git a/Documentation/x86/x86_64/00-INDEX b/Documentation/x86/x86_64/00-INDEX new file mode 100644 index 000000000000..92fc20ab5f0e --- /dev/null +++ b/Documentation/x86/x86_64/00-INDEX | |||
@@ -0,0 +1,16 @@ | |||
1 | 00-INDEX | ||
2 | - This file | ||
3 | boot-options.txt | ||
4 | - AMD64-specific boot options. | ||
5 | cpu-hotplug-spec | ||
6 | - Firmware support for CPU hotplug under Linux/x86-64 | ||
7 | fake-numa-for-cpusets | ||
8 | - Using numa=fake and CPUSets for Resource Management | ||
9 | kernel-stacks | ||
10 | - Context-specific per-processor interrupt stacks. | ||
11 | machinecheck | ||
12 | - Configurable sysfs parameters for the x86-64 machine check code. | ||
13 | mm.txt | ||
14 | - Memory layout of x86-64 (4 level page tables, 46 bits physical). | ||
15 | uefi.txt | ||
16 | - Booting Linux via Unified Extensible Firmware Interface. | ||
diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt new file mode 100644 index 000000000000..b0c7b6c4abda --- /dev/null +++ b/Documentation/x86/x86_64/boot-options.txt | |||
@@ -0,0 +1,314 @@ | |||
1 | AMD64 specific boot options | ||
2 | |||
3 | There are many others (usually documented in driver documentation), but | ||
4 | only the AMD64 specific ones are listed here. | ||
5 | |||
6 | Machine check | ||
7 | |||
8 | mce=off disable machine check | ||
9 | mce=bootlog Enable logging of machine checks left over from booting. | ||
10 | Disabled by default on AMD because some BIOS leave bogus ones. | ||
11 | If your BIOS doesn't do that it's a good idea to enable though | ||
12 | to make sure you log even machine check events that result | ||
13 | in a reboot. On Intel systems it is enabled by default. | ||
14 | mce=nobootlog | ||
15 | Disable boot machine check logging. | ||
16 | mce=tolerancelevel (number) | ||
17 | 0: always panic on uncorrected errors, log corrected errors | ||
18 | 1: panic or SIGBUS on uncorrected errors, log corrected errors | ||
19 | 2: SIGBUS or log uncorrected errors, log corrected errors | ||
20 | 3: never panic or SIGBUS, log all errors (for testing only) | ||
21 | Default is 1 | ||
22 | Can be also set using sysfs which is preferable. | ||
23 | |||
24 | nomce (for compatibility with i386): same as mce=off | ||
25 | |||
26 | Everything else is in sysfs now. | ||
27 | |||
28 | APICs | ||
29 | |||
30 | apic Use IO-APIC. Default | ||
31 | |||
32 | noapic Don't use the IO-APIC. | ||
33 | |||
34 | disableapic Don't use the local APIC | ||
35 | |||
36 | nolapic Don't use the local APIC (alias for i386 compatibility) | ||
37 | |||
38 | pirq=... See Documentation/i386/IO-APIC.txt | ||
39 | |||
40 | noapictimer Don't set up the APIC timer | ||
41 | |||
42 | no_timer_check Don't check the IO-APIC timer. This can work around | ||
43 | problems with incorrect timer initialization on some boards. | ||
44 | |||
45 | apicmaintimer Run time keeping from the local APIC timer instead | ||
46 | of using the PIT/HPET interrupt for this. This is useful | ||
47 | when the PIT/HPET interrupts are unreliable. | ||
48 | |||
49 | noapicmaintimer Don't do time keeping using the APIC timer. | ||
50 | Useful when this option was auto selected, but doesn't work. | ||
51 | |||
52 | apicpmtimer | ||
53 | Do APIC timer calibration using the pmtimer. Implies | ||
54 | apicmaintimer. Useful when your PIT timer is totally | ||
55 | broken. | ||
56 | |||
57 | disable_8254_timer / enable_8254_timer | ||
58 | Enable interrupt 0 timer routing over the 8254 in addition to over | ||
59 | the IO-APIC. The kernel tries to set a sensible default. | ||
60 | |||
61 | Early Console | ||
62 | |||
63 | syntax: earlyprintk=vga | ||
64 | earlyprintk=serial[,ttySn[,baudrate]] | ||
65 | |||
66 | The early console is useful when the kernel crashes before the | ||
67 | normal console is initialized. It is not enabled by | ||
68 | default because it has some cosmetic problems. | ||
69 | Append ,keep to not disable it when the real console takes over. | ||
70 | Only vga or serial at a time, not both. | ||
71 | Currently only ttyS0 and ttyS1 are supported. | ||
72 | Interaction with the standard serial driver is not very good. | ||
73 | The VGA output is eventually overwritten by the real console. | ||
74 | |||
75 | Timing | ||
76 | |||
77 | notsc | ||
78 | Don't use the CPU time stamp counter to read the wall time. | ||
79 | This can be used to work around timing problems on multiprocessor systems | ||
80 | with not properly synchronized CPUs. | ||
81 | |||
82 | report_lost_ticks | ||
83 | Report when timer interrupts are lost because some code turned off | ||
84 | interrupts for too long. | ||
85 | |||
86 | nmi_watchdog=NUMBER[,panic] | ||
87 | NUMBER can be: | ||
88 | 0 don't use an NMI watchdog | ||
89 | 1 use the IO-APIC timer for the NMI watchdog | ||
90 | 2 use the local APIC for the NMI watchdog using a performance counter. Note | ||
91 | This will use one performance counter and the local APIC's performance | ||
92 | vector. | ||
93 | When panic is specified panic when an NMI watchdog timeout occurs. | ||
94 | This is useful when you use a panic=... timeout and need the box | ||
95 | quickly up again. | ||
96 | |||
97 | nohpet | ||
98 | Don't use the HPET timer. | ||
99 | |||
100 | Idle loop | ||
101 | |||
102 | idle=poll | ||
103 | Don't do power saving in the idle loop using HLT, but poll for rescheduling | ||
104 | event. This will make the CPUs eat a lot more power, but may be useful | ||
105 | to get slightly better performance in multiprocessor benchmarks. It also | ||
106 | makes some profiling using performance counters more accurate. | ||
107 | Please note that on systems with MONITOR/MWAIT support (like Intel EM64T | ||
108 | CPUs) this option has no performance advantage over the normal idle loop. | ||
109 | It may also interact badly with hyperthreading. | ||
110 | |||
111 | Rebooting | ||
112 | |||
113 | reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old] | ||
114 | bios Use the CPU reboot vector for warm reset | ||
115 | warm Don't set the cold reboot flag | ||
116 | cold Set the cold reboot flag | ||
117 | triple Force a triple fault (init) | ||
118 | kbd Use the keyboard controller. cold reset (default) | ||
119 | acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the | ||
120 | ACPI reset does not work, the reboot path attempts the reset using | ||
121 | the keyboard controller. | ||
122 | efi Use efi reset_system runtime service. If EFI is not configured or the | ||
123 | EFI reset does not work, the reboot path attempts the reset using | ||
124 | the keyboard controller. | ||
125 | |||
126 | Using warm reset will be much faster especially on big memory | ||
127 | systems because the BIOS will not go through the memory check. | ||
128 | Disadvantage is that not all hardware will be completely reinitialized | ||
129 | on reboot so there may be boot problems on some systems. | ||
130 | |||
131 | reboot=force | ||
132 | |||
133 | Don't stop other CPUs on reboot. This can make reboot more reliable | ||
134 | in some cases. | ||
135 | |||
136 | Non Executable Mappings | ||
137 | |||
138 | noexec=on|off | ||
139 | |||
140 | on Enable(default) | ||
141 | off Disable | ||
142 | |||
143 | SMP | ||
144 | |||
145 | additional_cpus=NUM Allow NUM more CPUs for hotplug | ||
146 | (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec) | ||
147 | |||
148 | NUMA | ||
149 | |||
150 | numa=off Only set up a single NUMA node spanning all memory. | ||
151 | |||
152 | numa=noacpi Don't parse the SRAT table for NUMA setup | ||
153 | |||
154 | numa=fake=CMDLINE | ||
155 | If a number, fakes CMDLINE nodes and ignores NUMA setup of the | ||
156 | actual machine. Otherwise, system memory is configured | ||
157 | depending on the sizes and coefficients listed. For example: | ||
158 | numa=fake=2*512,1024,4*256,*128 | ||
159 | gives two 512M nodes, a 1024M node, four 256M nodes, and the | ||
160 | rest split into 128M chunks. If the last character of CMDLINE | ||
161 | is a *, the remaining memory is divided up equally among its | ||
162 | coefficient: | ||
163 | numa=fake=2*512,2* | ||
164 | gives two 512M nodes and the rest split into two nodes. | ||
165 | Otherwise, the remaining system RAM is allocated to an | ||
166 | additional node. | ||
167 | |||
168 | numa=hotadd=percent | ||
169 | Only allow hotadd memory to preallocate page structures upto | ||
170 | percent of already available memory. | ||
171 | numa=hotadd=0 will disable hotadd memory. | ||
172 | |||
173 | ACPI | ||
174 | |||
175 | acpi=off Don't enable ACPI | ||
176 | acpi=ht Use ACPI boot table parsing, but don't enable ACPI | ||
177 | interpreter | ||
178 | acpi=force Force ACPI on (currently not needed) | ||
179 | |||
180 | acpi=strict Disable out of spec ACPI workarounds. | ||
181 | |||
182 | acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt. | ||
183 | |||
184 | acpi=noirq Don't route interrupts | ||
185 | |||
186 | PCI | ||
187 | |||
188 | pci=off Don't use PCI | ||
189 | pci=conf1 Use conf1 access. | ||
190 | pci=conf2 Use conf2 access. | ||
191 | pci=rom Assign ROMs. | ||
192 | pci=assign-busses Assign busses | ||
193 | pci=irqmask=MASK Set PCI interrupt mask to MASK | ||
194 | pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says. | ||
195 | pci=noacpi Don't use ACPI to set up PCI interrupt routing. | ||
196 | |||
197 | IOMMU (input/output memory management unit) | ||
198 | |||
199 | Currently four x86-64 PCI-DMA mapping implementations exist: | ||
200 | |||
201 | 1. <arch/x86_64/kernel/pci-nommu.c>: use no hardware/software IOMMU at all | ||
202 | (e.g. because you have < 3 GB memory). | ||
203 | Kernel boot message: "PCI-DMA: Disabling IOMMU" | ||
204 | |||
205 | 2. <arch/x86_64/kernel/pci-gart.c>: AMD GART based hardware IOMMU. | ||
206 | Kernel boot message: "PCI-DMA: using GART IOMMU" | ||
207 | |||
208 | 3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used | ||
209 | e.g. if there is no hardware IOMMU in the system and it is need because | ||
210 | you have >3GB memory or told the kernel to us it (iommu=soft)) | ||
211 | Kernel boot message: "PCI-DMA: Using software bounce buffering | ||
212 | for IO (SWIOTLB)" | ||
213 | |||
214 | 4. <arch/x86_64/pci-calgary.c> : IBM Calgary hardware IOMMU. Used in IBM | ||
215 | pSeries and xSeries servers. This hardware IOMMU supports DMA address | ||
216 | mapping with memory protection, etc. | ||
217 | Kernel boot message: "PCI-DMA: Using Calgary IOMMU" | ||
218 | |||
219 | iommu=[<size>][,noagp][,off][,force][,noforce][,leak[=<nr_of_leak_pages>] | ||
220 | [,memaper[=<order>]][,merge][,forcesac][,fullflush][,nomerge] | ||
221 | [,noaperture][,calgary] | ||
222 | |||
223 | General iommu options: | ||
224 | off Don't initialize and use any kind of IOMMU. | ||
225 | noforce Don't force hardware IOMMU usage when it is not needed. | ||
226 | (default). | ||
227 | force Force the use of the hardware IOMMU even when it is | ||
228 | not actually needed (e.g. because < 3 GB memory). | ||
229 | soft Use software bounce buffering (SWIOTLB) (default for | ||
230 | Intel machines). This can be used to prevent the usage | ||
231 | of an available hardware IOMMU. | ||
232 | |||
233 | iommu options only relevant to the AMD GART hardware IOMMU: | ||
234 | <size> Set the size of the remapping area in bytes. | ||
235 | allowed Overwrite iommu off workarounds for specific chipsets. | ||
236 | fullflush Flush IOMMU on each allocation (default). | ||
237 | nofullflush Don't use IOMMU fullflush. | ||
238 | leak Turn on simple iommu leak tracing (only when | ||
239 | CONFIG_IOMMU_LEAK is on). Default number of leak pages | ||
240 | is 20. | ||
241 | memaper[=<order>] Allocate an own aperture over RAM with size 32MB<<order. | ||
242 | (default: order=1, i.e. 64MB) | ||
243 | merge Do scatter-gather (SG) merging. Implies "force" | ||
244 | (experimental). | ||
245 | nomerge Don't do scatter-gather (SG) merging. | ||
246 | noaperture Ask the IOMMU not to touch the aperture for AGP. | ||
247 | forcesac Force single-address cycle (SAC) mode for masks <40bits | ||
248 | (experimental). | ||
249 | noagp Don't initialize the AGP driver and use full aperture. | ||
250 | allowdac Allow double-address cycle (DAC) mode, i.e. DMA >4GB. | ||
251 | DAC is used with 32-bit PCI to push a 64-bit address in | ||
252 | two cycles. When off all DMA over >4GB is forced through | ||
253 | an IOMMU or software bounce buffering. | ||
254 | nodac Forbid DAC mode, i.e. DMA >4GB. | ||
255 | panic Always panic when IOMMU overflows. | ||
256 | calgary Use the Calgary IOMMU if it is available | ||
257 | |||
258 | iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU | ||
259 | implementation: | ||
260 | swiotlb=<pages>[,force] | ||
261 | <pages> Prereserve that many 128K pages for the software IO | ||
262 | bounce buffering. | ||
263 | force Force all IO through the software TLB. | ||
264 | |||
265 | Settings for the IBM Calgary hardware IOMMU currently found in IBM | ||
266 | pSeries and xSeries machines: | ||
267 | |||
268 | calgary=[64k,128k,256k,512k,1M,2M,4M,8M] | ||
269 | calgary=[translate_empty_slots] | ||
270 | calgary=[disable=<PCI bus number>] | ||
271 | panic Always panic when IOMMU overflows | ||
272 | |||
273 | 64k,...,8M - Set the size of each PCI slot's translation table | ||
274 | when using the Calgary IOMMU. This is the size of the translation | ||
275 | table itself in main memory. The smallest table, 64k, covers an IO | ||
276 | space of 32MB; the largest, 8MB table, can cover an IO space of | ||
277 | 4GB. Normally the kernel will make the right choice by itself. | ||
278 | |||
279 | translate_empty_slots - Enable translation even on slots that have | ||
280 | no devices attached to them, in case a device will be hotplugged | ||
281 | in the future. | ||
282 | |||
283 | disable=<PCI bus number> - Disable translation on a given PHB. For | ||
284 | example, the built-in graphics adapter resides on the first bridge | ||
285 | (PCI bus number 0); if translation (isolation) is enabled on this | ||
286 | bridge, X servers that access the hardware directly from user | ||
287 | space might stop working. Use this option if you have devices that | ||
288 | are accessed from userspace directly on some PCI host bridge. | ||
289 | |||
290 | Debugging | ||
291 | |||
292 | oops=panic Always panic on oopses. Default is to just kill the process, | ||
293 | but there is a small probability of deadlocking the machine. | ||
294 | This will also cause panics on machine check exceptions. | ||
295 | Useful together with panic=30 to trigger a reboot. | ||
296 | |||
297 | kstack=N Print N words from the kernel stack in oops dumps. | ||
298 | |||
299 | pagefaulttrace Dump all page faults. Only useful for extreme debugging | ||
300 | and will create a lot of output. | ||
301 | |||
302 | call_trace=[old|both|newfallback|new] | ||
303 | old: use old inexact backtracer | ||
304 | new: use new exact dwarf2 unwinder | ||
305 | both: print entries from both | ||
306 | newfallback: use new unwinder but fall back to old if it gets | ||
307 | stuck (default) | ||
308 | |||
309 | Miscellaneous | ||
310 | |||
311 | nogbpages | ||
312 | Do not use GB pages for kernel direct mappings. | ||
313 | gbpages | ||
314 | Use GB pages for kernel direct mappings. | ||
diff --git a/Documentation/x86/x86_64/cpu-hotplug-spec b/Documentation/x86/x86_64/cpu-hotplug-spec new file mode 100644 index 000000000000..3c23e0587db3 --- /dev/null +++ b/Documentation/x86/x86_64/cpu-hotplug-spec | |||
@@ -0,0 +1,21 @@ | |||
1 | Firmware support for CPU hotplug under Linux/x86-64 | ||
2 | --------------------------------------------------- | ||
3 | |||
4 | Linux/x86-64 supports CPU hotplug now. For various reasons Linux wants to | ||
5 | know in advance of boot time the maximum number of CPUs that could be plugged | ||
6 | into the system. ACPI 3.0 currently has no official way to supply | ||
7 | this information from the firmware to the operating system. | ||
8 | |||
9 | In ACPI each CPU needs an LAPIC object in the MADT table (5.2.11.5 in the | ||
10 | ACPI 3.0 specification). ACPI already has the concept of disabled LAPIC | ||
11 | objects by setting the Enabled bit in the LAPIC object to zero. | ||
12 | |||
13 | For CPU hotplug Linux/x86-64 expects now that any possible future hotpluggable | ||
14 | CPU is already available in the MADT. If the CPU is not available yet | ||
15 | it should have its LAPIC Enabled bit set to 0. Linux will use the number | ||
16 | of disabled LAPICs to compute the maximum number of future CPUs. | ||
17 | |||
18 | In the worst case the user can overwrite this choice using a command line | ||
19 | option (additional_cpus=...), but it is recommended to supply the correct | ||
20 | number (or a reasonable approximation of it, with erring towards more not less) | ||
21 | in the MADT to avoid manual configuration. | ||
diff --git a/Documentation/x86/x86_64/fake-numa-for-cpusets b/Documentation/x86/x86_64/fake-numa-for-cpusets new file mode 100644 index 000000000000..d1a985c5b00a --- /dev/null +++ b/Documentation/x86/x86_64/fake-numa-for-cpusets | |||
@@ -0,0 +1,66 @@ | |||
1 | Using numa=fake and CPUSets for Resource Management | ||
2 | Written by David Rientjes <rientjes@cs.washington.edu> | ||
3 | |||
4 | This document describes how the numa=fake x86_64 command-line option can be used | ||
5 | in conjunction with cpusets for coarse memory management. Using this feature, | ||
6 | you can create fake NUMA nodes that represent contiguous chunks of memory and | ||
7 | assign them to cpusets and their attached tasks. This is a way of limiting the | ||
8 | amount of system memory that are available to a certain class of tasks. | ||
9 | |||
10 | For more information on the features of cpusets, see Documentation/cpusets.txt. | ||
11 | There are a number of different configurations you can use for your needs. For | ||
12 | more information on the numa=fake command line option and its various ways of | ||
13 | configuring fake nodes, see Documentation/x86_64/boot-options.txt. | ||
14 | |||
15 | For the purposes of this introduction, we'll assume a very primitive NUMA | ||
16 | emulation setup of "numa=fake=4*512,". This will split our system memory into | ||
17 | four equal chunks of 512M each that we can now use to assign to cpusets. As | ||
18 | you become more familiar with using this combination for resource control, | ||
19 | you'll determine a better setup to minimize the number of nodes you have to deal | ||
20 | with. | ||
21 | |||
22 | A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: | ||
23 | |||
24 | Faking node 0 at 0000000000000000-0000000020000000 (512MB) | ||
25 | Faking node 1 at 0000000020000000-0000000040000000 (512MB) | ||
26 | Faking node 2 at 0000000040000000-0000000060000000 (512MB) | ||
27 | Faking node 3 at 0000000060000000-0000000080000000 (512MB) | ||
28 | ... | ||
29 | On node 0 totalpages: 130975 | ||
30 | On node 1 totalpages: 131072 | ||
31 | On node 2 totalpages: 131072 | ||
32 | On node 3 totalpages: 131072 | ||
33 | |||
34 | Now following the instructions for mounting the cpusets filesystem from | ||
35 | Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory | ||
36 | address spaces) to individual cpusets: | ||
37 | |||
38 | [root@xroads /]# mkdir exampleset | ||
39 | [root@xroads /]# mount -t cpuset none exampleset | ||
40 | [root@xroads /]# mkdir exampleset/ddset | ||
41 | [root@xroads /]# cd exampleset/ddset | ||
42 | [root@xroads /exampleset/ddset]# echo 0-1 > cpus | ||
43 | [root@xroads /exampleset/ddset]# echo 0-1 > mems | ||
44 | |||
45 | Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for | ||
46 | memory allocations (1G). | ||
47 | |||
48 | You can now assign tasks to these cpusets to limit the memory resources | ||
49 | available to them according to the fake nodes assigned as mems: | ||
50 | |||
51 | [root@xroads /exampleset/ddset]# echo $$ > tasks | ||
52 | [root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G | ||
53 | [1] 13425 | ||
54 | |||
55 | Notice the difference between the system memory usage as reported by | ||
56 | /proc/meminfo between the restricted cpuset case above and the unrestricted | ||
57 | case (i.e. running the same 'dd' command without assigning it to a fake NUMA | ||
58 | cpuset): | ||
59 | Unrestricted Restricted | ||
60 | MemTotal: 3091900 kB 3091900 kB | ||
61 | MemFree: 42113 kB 1513236 kB | ||
62 | |||
63 | This allows for coarse memory management for the tasks you assign to particular | ||
64 | cpusets. Since cpusets can form a hierarchy, you can create some pretty | ||
65 | interesting combinations of use-cases for various classes of tasks for your | ||
66 | memory management needs. | ||
diff --git a/Documentation/x86/x86_64/kernel-stacks b/Documentation/x86/x86_64/kernel-stacks new file mode 100644 index 000000000000..5ad65d51fb95 --- /dev/null +++ b/Documentation/x86/x86_64/kernel-stacks | |||
@@ -0,0 +1,99 @@ | |||
1 | Most of the text from Keith Owens, hacked by AK | ||
2 | |||
3 | x86_64 page size (PAGE_SIZE) is 4K. | ||
4 | |||
5 | Like all other architectures, x86_64 has a kernel stack for every | ||
6 | active thread. These thread stacks are THREAD_SIZE (2*PAGE_SIZE) big. | ||
7 | These stacks contain useful data as long as a thread is alive or a | ||
8 | zombie. While the thread is in user space the kernel stack is empty | ||
9 | except for the thread_info structure at the bottom. | ||
10 | |||
11 | In addition to the per thread stacks, there are specialized stacks | ||
12 | associated with each CPU. These stacks are only used while the kernel | ||
13 | is in control on that CPU; when a CPU returns to user space the | ||
14 | specialized stacks contain no useful data. The main CPU stacks are: | ||
15 | |||
16 | * Interrupt stack. IRQSTACKSIZE | ||
17 | |||
18 | Used for external hardware interrupts. If this is the first external | ||
19 | hardware interrupt (i.e. not a nested hardware interrupt) then the | ||
20 | kernel switches from the current task to the interrupt stack. Like | ||
21 | the split thread and interrupt stacks on i386 (with CONFIG_4KSTACKS), | ||
22 | this gives more room for kernel interrupt processing without having | ||
23 | to increase the size of every per thread stack. | ||
24 | |||
25 | The interrupt stack is also used when processing a softirq. | ||
26 | |||
27 | Switching to the kernel interrupt stack is done by software based on a | ||
28 | per CPU interrupt nest counter. This is needed because x86-64 "IST" | ||
29 | hardware stacks cannot nest without races. | ||
30 | |||
31 | x86_64 also has a feature which is not available on i386, the ability | ||
32 | to automatically switch to a new stack for designated events such as | ||
33 | double fault or NMI, which makes it easier to handle these unusual | ||
34 | events on x86_64. This feature is called the Interrupt Stack Table | ||
35 | (IST). There can be up to 7 IST entries per CPU. The IST code is an | ||
36 | index into the Task State Segment (TSS). The IST entries in the TSS | ||
37 | point to dedicated stacks; each stack can be a different size. | ||
38 | |||
39 | An IST is selected by a non-zero value in the IST field of an | ||
40 | interrupt-gate descriptor. When an interrupt occurs and the hardware | ||
41 | loads such a descriptor, the hardware automatically sets the new stack | ||
42 | pointer based on the IST value, then invokes the interrupt handler. If | ||
43 | software wants to allow nested IST interrupts then the handler must | ||
44 | adjust the IST values on entry to and exit from the interrupt handler. | ||
45 | (This is occasionally done, e.g. for debug exceptions.) | ||
46 | |||
47 | Events with different IST codes (i.e. with different stacks) can be | ||
48 | nested. For example, a debug interrupt can safely be interrupted by an | ||
49 | NMI. arch/x86_64/kernel/entry.S::paranoidentry adjusts the stack | ||
50 | pointers on entry to and exit from all IST events, in theory allowing | ||
51 | IST events with the same code to be nested. However in most cases, the | ||
52 | stack size allocated to an IST assumes no nesting for the same code. | ||
53 | If that assumption is ever broken then the stacks will become corrupt. | ||
54 | |||
55 | The currently assigned IST stacks are :- | ||
56 | |||
57 | * STACKFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). | ||
58 | |||
59 | Used for interrupt 12 - Stack Fault Exception (#SS). | ||
60 | |||
61 | This allows the CPU to recover from invalid stack segments. Rarely | ||
62 | happens. | ||
63 | |||
64 | * DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). | ||
65 | |||
66 | Used for interrupt 8 - Double Fault Exception (#DF). | ||
67 | |||
68 | Invoked when handling one exception causes another exception. Happens | ||
69 | when the kernel is very confused (e.g. kernel stack pointer corrupt). | ||
70 | Using a separate stack allows the kernel to recover from it well enough | ||
71 | in many cases to still output an oops. | ||
72 | |||
73 | * NMI_STACK. EXCEPTION_STKSZ (PAGE_SIZE). | ||
74 | |||
75 | Used for non-maskable interrupts (NMI). | ||
76 | |||
77 | NMI can be delivered at any time, including when the kernel is in the | ||
78 | middle of switching stacks. Using IST for NMI events avoids making | ||
79 | assumptions about the previous state of the kernel stack. | ||
80 | |||
81 | * DEBUG_STACK. DEBUG_STKSZ | ||
82 | |||
83 | Used for hardware debug interrupts (interrupt 1) and for software | ||
84 | debug interrupts (INT3). | ||
85 | |||
86 | When debugging a kernel, debug interrupts (both hardware and | ||
87 | software) can occur at any time. Using IST for these interrupts | ||
88 | avoids making assumptions about the previous state of the kernel | ||
89 | stack. | ||
90 | |||
91 | * MCE_STACK. EXCEPTION_STKSZ (PAGE_SIZE). | ||
92 | |||
93 | Used for interrupt 18 - Machine Check Exception (#MC). | ||
94 | |||
95 | MCE can be delivered at any time, including when the kernel is in the | ||
96 | middle of switching stacks. Using IST for MCE events avoids making | ||
97 | assumptions about the previous state of the kernel stack. | ||
98 | |||
99 | For more details see the Intel IA32 or AMD AMD64 architecture manuals. | ||
diff --git a/Documentation/x86/x86_64/machinecheck b/Documentation/x86/x86_64/machinecheck new file mode 100644 index 000000000000..a05e58e7b159 --- /dev/null +++ b/Documentation/x86/x86_64/machinecheck | |||
@@ -0,0 +1,77 @@ | |||
1 | |||
2 | Configurable sysfs parameters for the x86-64 machine check code. | ||
3 | |||
4 | Machine checks report internal hardware error conditions detected | ||
5 | by the CPU. Uncorrected errors typically cause a machine check | ||
6 | (often with panic), corrected ones cause a machine check log entry. | ||
7 | |||
8 | Machine checks are organized in banks (normally associated with | ||
9 | a hardware subsystem) and subevents in a bank. The exact meaning | ||
10 | of the banks and subevent is CPU specific. | ||
11 | |||
12 | mcelog knows how to decode them. | ||
13 | |||
14 | When you see the "Machine check errors logged" message in the system | ||
15 | log then mcelog should run to collect and decode machine check entries | ||
16 | from /dev/mcelog. Normally mcelog should be run regularly from a cronjob. | ||
17 | |||
18 | Each CPU has a directory in /sys/devices/system/machinecheck/machinecheckN | ||
19 | (N = CPU number) | ||
20 | |||
21 | The directory contains some configurable entries: | ||
22 | |||
23 | Entries: | ||
24 | |||
25 | bankNctl | ||
26 | (N bank number) | ||
27 | 64bit Hex bitmask enabling/disabling specific subevents for bank N | ||
28 | When a bit in the bitmask is zero then the respective | ||
29 | subevent will not be reported. | ||
30 | By default all events are enabled. | ||
31 | Note that BIOS maintain another mask to disable specific events | ||
32 | per bank. This is not visible here | ||
33 | |||
34 | The following entries appear for each CPU, but they are truly shared | ||
35 | between all CPUs. | ||
36 | |||
37 | check_interval | ||
38 | How often to poll for corrected machine check errors, in seconds | ||
39 | (Note output is hexademical). Default 5 minutes. When the poller | ||
40 | finds MCEs it triggers an exponential speedup (poll more often) on | ||
41 | the polling interval. When the poller stops finding MCEs, it | ||
42 | triggers an exponential backoff (poll less often) on the polling | ||
43 | interval. The check_interval variable is both the initial and | ||
44 | maximum polling interval. | ||
45 | |||
46 | tolerant | ||
47 | Tolerance level. When a machine check exception occurs for a non | ||
48 | corrected machine check the kernel can take different actions. | ||
49 | Since machine check exceptions can happen any time it is sometimes | ||
50 | risky for the kernel to kill a process because it defies | ||
51 | normal kernel locking rules. The tolerance level configures | ||
52 | how hard the kernel tries to recover even at some risk of | ||
53 | deadlock. Higher tolerant values trade potentially better uptime | ||
54 | with the risk of a crash or even corruption (for tolerant >= 3). | ||
55 | |||
56 | 0: always panic on uncorrected errors, log corrected errors | ||
57 | 1: panic or SIGBUS on uncorrected errors, log corrected errors | ||
58 | 2: SIGBUS or log uncorrected errors, log corrected errors | ||
59 | 3: never panic or SIGBUS, log all errors (for testing only) | ||
60 | |||
61 | Default: 1 | ||
62 | |||
63 | Note this only makes a difference if the CPU allows recovery | ||
64 | from a machine check exception. Current x86 CPUs generally do not. | ||
65 | |||
66 | trigger | ||
67 | Program to run when a machine check event is detected. | ||
68 | This is an alternative to running mcelog regularly from cron | ||
69 | and allows to detect events faster. | ||
70 | |||
71 | TBD document entries for AMD threshold interrupt configuration | ||
72 | |||
73 | For more details about the x86 machine check architecture | ||
74 | see the Intel and AMD architecture manuals from their developer websites. | ||
75 | |||
76 | For more details about the architecture see | ||
77 | see http://one.firstfloor.org/~andi/mce.pdf | ||
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt new file mode 100644 index 000000000000..efce75097369 --- /dev/null +++ b/Documentation/x86/x86_64/mm.txt | |||
@@ -0,0 +1,28 @@ | |||
1 | |||
2 | <previous description obsolete, deleted> | ||
3 | |||
4 | Virtual memory map with 4 level page tables: | ||
5 | |||
6 | 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm | ||
7 | hole caused by [48:63] sign extension | ||
8 | ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole | ||
9 | ffff810000000000 - ffffc0ffffffffff (=46 bits) direct mapping of all phys. memory | ||
10 | ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole | ||
11 | ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space | ||
12 | ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) | ||
13 | ... unused hole ... | ||
14 | ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0 | ||
15 | ffffffffa0000000 - fffffffffff00000 (=1536 MB) module mapping space | ||
16 | |||
17 | The direct mapping covers all memory in the system up to the highest | ||
18 | memory address (this means in some cases it can also include PCI memory | ||
19 | holes). | ||
20 | |||
21 | vmalloc space is lazily synchronized into the different PML4 pages of | ||
22 | the processes using the page fault handler, with init_level4_pgt as | ||
23 | reference. | ||
24 | |||
25 | Current X86-64 implementations only support 40 bits of address space, | ||
26 | but we support up to 46 bits. This expands into MBZ space in the page tables. | ||
27 | |||
28 | -Andi Kleen, Jul 2004 | ||
diff --git a/Documentation/x86/x86_64/uefi.txt b/Documentation/x86/x86_64/uefi.txt new file mode 100644 index 000000000000..7d77120a5184 --- /dev/null +++ b/Documentation/x86/x86_64/uefi.txt | |||
@@ -0,0 +1,38 @@ | |||
1 | General note on [U]EFI x86_64 support | ||
2 | ------------------------------------- | ||
3 | |||
4 | The nomenclature EFI and UEFI are used interchangeably in this document. | ||
5 | |||
6 | Although the tools below are _not_ needed for building the kernel, | ||
7 | the needed bootloader support and associated tools for x86_64 platforms | ||
8 | with EFI firmware and specifications are listed below. | ||
9 | |||
10 | 1. UEFI specification: http://www.uefi.org | ||
11 | |||
12 | 2. Booting Linux kernel on UEFI x86_64 platform requires bootloader | ||
13 | support. Elilo with x86_64 support can be used. | ||
14 | |||
15 | 3. x86_64 platform with EFI/UEFI firmware. | ||
16 | |||
17 | Mechanics: | ||
18 | --------- | ||
19 | - Build the kernel with the following configuration. | ||
20 | CONFIG_FB_EFI=y | ||
21 | CONFIG_FRAMEBUFFER_CONSOLE=y | ||
22 | If EFI runtime services are expected, the following configuration should | ||
23 | be selected. | ||
24 | CONFIG_EFI=y | ||
25 | CONFIG_EFI_VARS=y or m # optional | ||
26 | - Create a VFAT partition on the disk | ||
27 | - Copy the following to the VFAT partition: | ||
28 | elilo bootloader with x86_64 support, elilo configuration file, | ||
29 | kernel image built in first step and corresponding | ||
30 | initrd. Instructions on building elilo and its dependencies | ||
31 | can be found in the elilo sourceforge project. | ||
32 | - Boot to EFI shell and invoke elilo choosing the kernel image built | ||
33 | in first step. | ||
34 | - If some or all EFI runtime services don't work, you can try following | ||
35 | kernel command line parameters to turn off some or all EFI runtime | ||
36 | services. | ||
37 | noefi turn off all EFI runtime services | ||
38 | reboot_type=k turn off EFI reboot runtime service | ||