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Commit | Line | Data |
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1da177e4 LT |
1 | menu "Kernel hacking" |
2 | ||
55f327fa | 3 | config TRACE_IRQFLAGS_SUPPORT |
d013a27c | 4 | def_bool y |
55f327fa | 5 | |
1da177e4 LT |
6 | source "lib/Kconfig.debug" |
7 | ||
aeb9dd1d LB |
8 | config EARLY_PRINTK_USB |
9 | bool | |
10 | ||
6bcb13b3 BC |
11 | config X86_VERBOSE_BOOTUP |
12 | bool "Enable verbose x86 bootup info messages" | |
13 | default y | |
8f9ca475 | 14 | ---help--- |
6bcb13b3 BC |
15 | Enables the informational output from the decompression stage |
16 | (e.g. bzImage) of the boot. If you disable this you will still | |
17 | see errors. Disable this if you want silent bootup. | |
18 | ||
1da177e4 | 19 | config EARLY_PRINTK |
6a108a14 | 20 | bool "Early printk" if EXPERT |
1da177e4 | 21 | default y |
8f9ca475 | 22 | ---help--- |
1da177e4 LT |
23 | Write kernel log output directly into the VGA buffer or to a serial |
24 | port. | |
25 | ||
26 | This is useful for kernel debugging when your machine crashes very | |
27 | early before the console code is initialized. For normal operation | |
28 | it is not recommended because it looks ugly and doesn't cooperate | |
aeb9dd1d | 29 | with klogd/syslogd or the X server. You should normally say N here, |
1da177e4 LT |
30 | unless you want to debug such a crash. |
31 | ||
5c05917e YL |
32 | config EARLY_PRINTK_DBGP |
33 | bool "Early printk via EHCI debug port" | |
9749986a | 34 | depends on EARLY_PRINTK && PCI |
aeb9dd1d | 35 | select EARLY_PRINTK_USB |
8f9ca475 | 36 | ---help--- |
5c05917e YL |
37 | Write kernel log output directly into the EHCI debug port. |
38 | ||
39 | This is useful for kernel debugging when your machine crashes very | |
40 | early before the console code is initialized. For normal operation | |
41 | it is not recommended because it looks ugly and doesn't cooperate | |
aeb9dd1d | 42 | with klogd/syslogd or the X server. You should normally say N here, |
5c05917e YL |
43 | unless you want to debug such a crash. You need usb debug device. |
44 | ||
72548e83 MF |
45 | config EARLY_PRINTK_EFI |
46 | bool "Early printk via the EFI framebuffer" | |
47 | depends on EFI && EARLY_PRINTK | |
48 | select FONT_SUPPORT | |
49 | ---help--- | |
50 | Write kernel log output directly into the EFI framebuffer. | |
51 | ||
52 | This is useful for kernel debugging when your machine crashes very | |
53 | early before the console code is initialized. | |
54 | ||
aeb9dd1d LB |
55 | config EARLY_PRINTK_USB_XDBC |
56 | bool "Early printk via the xHCI debug port" | |
57 | depends on EARLY_PRINTK && PCI | |
58 | select EARLY_PRINTK_USB | |
59 | ---help--- | |
60 | Write kernel log output directly into the xHCI debug port. | |
61 | ||
62 | One use for this feature is kernel debugging, for example when your | |
63 | machine crashes very early before the regular console code is | |
64 | initialized. Other uses include simpler, lockless logging instead of | |
65 | a full-blown printk console driver + klogd. | |
66 | ||
67 | For normal production environments this is normally not recommended, | |
68 | because it doesn't feed events into klogd/syslogd and doesn't try to | |
69 | print anything on the screen. | |
70 | ||
71 | You should normally say N here, unless you want to debug early | |
72 | crashes or need a very simple printk logging facility. | |
73 | ||
e1a58320 SS |
74 | config X86_PTDUMP_CORE |
75 | def_bool n | |
76 | ||
926e5392 | 77 | config X86_PTDUMP |
8609d1b5 | 78 | tristate "Export kernel pagetable layout to userspace via debugfs" |
fe770bf0 | 79 | depends on DEBUG_KERNEL |
926e5392 | 80 | select DEBUG_FS |
e1a58320 | 81 | select X86_PTDUMP_CORE |
8f9ca475 | 82 | ---help--- |
926e5392 AV |
83 | Say Y here if you want to show the kernel pagetable layout in a |
84 | debugfs file. This information is only useful for kernel developers | |
85 | who are working in architecture specific areas of the kernel. | |
86 | It is probably not a good idea to enable this feature in a production | |
87 | kernel. | |
88 | If in doubt, say "N" | |
89 | ||
11cc8512 BP |
90 | config EFI_PGT_DUMP |
91 | bool "Dump the EFI pagetable" | |
e1a58320 SS |
92 | depends on EFI |
93 | select X86_PTDUMP_CORE | |
11cc8512 BP |
94 | ---help--- |
95 | Enable this if you want to dump the EFI page table before | |
96 | enabling virtual mode. This can be used to debug miscellaneous | |
97 | issues with the mapping of the EFI runtime regions into that | |
98 | table. | |
99 | ||
e1a58320 SS |
100 | config DEBUG_WX |
101 | bool "Warn on W+X mappings at boot" | |
e1a58320 SS |
102 | select X86_PTDUMP_CORE |
103 | ---help--- | |
104 | Generate a warning if any W+X mappings are found at boot. | |
105 | ||
106 | This is useful for discovering cases where the kernel is leaving | |
107 | W+X mappings after applying NX, as such mappings are a security risk. | |
108 | ||
109 | Look for a message in dmesg output like this: | |
110 | ||
111 | x86/mm: Checked W+X mappings: passed, no W+X pages found. | |
112 | ||
113 | or like this, if the check failed: | |
114 | ||
115 | x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found. | |
116 | ||
117 | Note that even if the check fails, your kernel is possibly | |
118 | still fine, as W+X mappings are not a security hole in | |
119 | themselves, what they do is that they make the exploitation | |
120 | of other unfixed kernel bugs easier. | |
121 | ||
122 | There is no runtime or memory usage effect of this option | |
123 | once the kernel has booted up - it's a one time check. | |
124 | ||
125 | If in doubt, say "Y". | |
126 | ||
102e41fd AK |
127 | config DOUBLEFAULT |
128 | default y | |
6a108a14 | 129 | bool "Enable doublefault exception handler" if EXPERT |
8f9ca475 | 130 | ---help--- |
d013a27c RD |
131 | This option allows trapping of rare doublefault exceptions that |
132 | would otherwise cause a system to silently reboot. Disabling this | |
133 | option saves about 4k and might cause you much additional grey | |
134 | hair. | |
135 | ||
3df3212f AS |
136 | config DEBUG_TLBFLUSH |
137 | bool "Set upper limit of TLB entries to flush one-by-one" | |
cd69aa6b | 138 | depends on DEBUG_KERNEL |
3df3212f AS |
139 | ---help--- |
140 | ||
141 | X86-only for now. | |
142 | ||
143 | This option allows the user to tune the amount of TLB entries the | |
144 | kernel flushes one-by-one instead of doing a full TLB flush. In | |
145 | certain situations, the former is cheaper. This is controlled by the | |
146 | tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it | |
147 | to -1, the code flushes the whole TLB unconditionally. Otherwise, | |
148 | for positive values of it, the kernel will use single TLB entry | |
149 | invalidating instructions according to the following formula: | |
150 | ||
151 | flush_entries <= active_tlb_entries / 2^tlb_flushall_shift | |
152 | ||
153 | If in doubt, say "N". | |
154 | ||
d013a27c RD |
155 | config IOMMU_DEBUG |
156 | bool "Enable IOMMU debugging" | |
966396d3 | 157 | depends on GART_IOMMU && DEBUG_KERNEL |
d013a27c | 158 | depends on X86_64 |
8f9ca475 | 159 | ---help--- |
d013a27c RD |
160 | Force the IOMMU to on even when you have less than 4GB of |
161 | memory and add debugging code. On overflow always panic. And | |
162 | allow to enable IOMMU leak tracing. Can be disabled at boot | |
163 | time with iommu=noforce. This will also enable scatter gather | |
164 | list merging. Currently not recommended for production | |
165 | code. When you use it make sure you have a big enough | |
166 | IOMMU/AGP aperture. Most of the options enabled by this can | |
167 | be set more finegrained using the iommu= command line | |
395cf969 | 168 | options. See Documentation/x86/x86_64/boot-options.txt for more |
d013a27c RD |
169 | details. |
170 | ||
2be69c79 JR |
171 | config IOMMU_STRESS |
172 | bool "Enable IOMMU stress-test mode" | |
173 | ---help--- | |
174 | This option disables various optimizations in IOMMU related | |
175 | code to do real stress testing of the IOMMU code. This option | |
176 | will cause a performance drop and should only be enabled for | |
177 | testing. | |
178 | ||
d013a27c RD |
179 | config IOMMU_LEAK |
180 | bool "IOMMU leak tracing" | |
19c1a6f5 | 181 | depends on IOMMU_DEBUG && DMA_API_DEBUG |
8f9ca475 | 182 | ---help--- |
d013a27c RD |
183 | Add a simple leak tracer to the IOMMU code. This is useful when you |
184 | are debugging a buggy device driver that leaks IOMMU mappings. | |
185 | ||
6bc5c366 PP |
186 | config HAVE_MMIOTRACE_SUPPORT |
187 | def_bool y | |
8b7d89d0 | 188 | |
ca0e9bad | 189 | config X86_DECODER_SELFTEST |
cbe5c34c OH |
190 | bool "x86 instruction decoder selftest" |
191 | depends on DEBUG_KERNEL && KPROBES | |
f8f20234 | 192 | depends on !COMPILE_TEST |
ca0e9bad MH |
193 | ---help--- |
194 | Perform x86 instruction decoder selftests at build time. | |
195 | This option is useful for checking the sanity of x86 instruction | |
196 | decoder code. | |
197 | If unsure, say "N". | |
198 | ||
6e7c4025 IM |
199 | # |
200 | # IO delay types: | |
201 | # | |
202 | ||
203 | config IO_DELAY_TYPE_0X80 | |
204 | int | |
205 | default "0" | |
206 | ||
207 | config IO_DELAY_TYPE_0XED | |
208 | int | |
209 | default "1" | |
210 | ||
211 | config IO_DELAY_TYPE_UDELAY | |
212 | int | |
213 | default "2" | |
214 | ||
215 | config IO_DELAY_TYPE_NONE | |
216 | int | |
217 | default "3" | |
218 | ||
219 | choice | |
220 | prompt "IO delay type" | |
fd59e9e9 | 221 | default IO_DELAY_0X80 |
6e7c4025 IM |
222 | |
223 | config IO_DELAY_0X80 | |
224 | bool "port 0x80 based port-IO delay [recommended]" | |
8f9ca475 | 225 | ---help--- |
6e7c4025 IM |
226 | This is the traditional Linux IO delay used for in/out_p. |
227 | It is the most tested hence safest selection here. | |
228 | ||
229 | config IO_DELAY_0XED | |
230 | bool "port 0xed based port-IO delay" | |
8f9ca475 | 231 | ---help--- |
6e7c4025 IM |
232 | Use port 0xed as the IO delay. This frees up port 0x80 which is |
233 | often used as a hardware-debug port. | |
234 | ||
235 | config IO_DELAY_UDELAY | |
236 | bool "udelay based port-IO delay" | |
8f9ca475 | 237 | ---help--- |
6e7c4025 IM |
238 | Use udelay(2) as the IO delay method. This provides the delay |
239 | while not having any side-effect on the IO port space. | |
240 | ||
241 | config IO_DELAY_NONE | |
242 | bool "no port-IO delay" | |
8f9ca475 | 243 | ---help--- |
6e7c4025 IM |
244 | No port-IO delay. Will break on old boxes that require port-IO |
245 | delay for certain operations. Should work on most new machines. | |
246 | ||
247 | endchoice | |
248 | ||
249 | if IO_DELAY_0X80 | |
250 | config DEFAULT_IO_DELAY_TYPE | |
251 | int | |
252 | default IO_DELAY_TYPE_0X80 | |
253 | endif | |
254 | ||
255 | if IO_DELAY_0XED | |
256 | config DEFAULT_IO_DELAY_TYPE | |
257 | int | |
258 | default IO_DELAY_TYPE_0XED | |
259 | endif | |
260 | ||
261 | if IO_DELAY_UDELAY | |
262 | config DEFAULT_IO_DELAY_TYPE | |
263 | int | |
264 | default IO_DELAY_TYPE_UDELAY | |
265 | endif | |
266 | ||
267 | if IO_DELAY_NONE | |
268 | config DEFAULT_IO_DELAY_TYPE | |
269 | int | |
270 | default IO_DELAY_TYPE_NONE | |
271 | endif | |
b02aae9c | 272 | |
6d7d7433 HY |
273 | config DEBUG_BOOT_PARAMS |
274 | bool "Debug boot parameters" | |
275 | depends on DEBUG_KERNEL | |
276 | depends on DEBUG_FS | |
8f9ca475 | 277 | ---help--- |
6d7d7433 HY |
278 | This option will cause struct boot_params to be exported via debugfs. |
279 | ||
0c42f392 | 280 | config CPA_DEBUG |
971a52d6 | 281 | bool "CPA self-test code" |
f316fe68 | 282 | depends on DEBUG_KERNEL |
8f9ca475 | 283 | ---help--- |
971a52d6 | 284 | Do change_page_attr() self-tests every 30 seconds. |
0c42f392 | 285 | |
60a3cdd0 IM |
286 | config OPTIMIZE_INLINING |
287 | bool "Allow gcc to uninline functions marked 'inline'" | |
8f9ca475 | 288 | ---help--- |
60a3cdd0 IM |
289 | This option determines if the kernel forces gcc to inline the functions |
290 | developers have marked 'inline'. Doing so takes away freedom from gcc to | |
291 | do what it thinks is best, which is desirable for the gcc 3.x series of | |
292 | compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
63fb7085 SW |
293 | enabling this option will generate a smaller kernel there. Hopefully |
294 | this algorithm is so good that allowing gcc 4.x and above to make the | |
295 | decision will become the default in the future. Until then this option | |
296 | is there to test gcc for this. | |
c9af1e33 | 297 | |
3f9b5cc0 IM |
298 | If unsure, say N. |
299 | ||
a97439aa AL |
300 | config DEBUG_ENTRY |
301 | bool "Debug low-level entry code" | |
302 | depends on DEBUG_KERNEL | |
303 | ---help--- | |
304 | This option enables sanity checks in x86's low-level entry code. | |
305 | Some of these sanity checks may slow down kernel entries and | |
306 | exits or otherwise impact performance. | |
307 | ||
308 | This is currently used to help test NMI code. | |
309 | ||
310 | If unsure, say N. | |
311 | ||
99e8b9ca DZ |
312 | config DEBUG_NMI_SELFTEST |
313 | bool "NMI Selftest" | |
4f941c57 | 314 | depends on DEBUG_KERNEL && X86_LOCAL_APIC |
99e8b9ca DZ |
315 | ---help--- |
316 | Enabling this option turns on a quick NMI selftest to verify | |
317 | that the NMI behaves correctly. | |
318 | ||
319 | This might help diagnose strange hangs that rely on NMI to | |
320 | function properly. | |
321 | ||
322 | If unsure, say N. | |
323 | ||
28a375df BD |
324 | config DEBUG_IMR_SELFTEST |
325 | bool "Isolated Memory Region self test" | |
326 | default n | |
327 | depends on INTEL_IMR | |
328 | ---help--- | |
329 | This option enables automated sanity testing of the IMR code. | |
330 | Some simple tests are run to verify IMR bounds checking, alignment | |
331 | and overlapping. This option is really only useful if you are | |
332 | debugging an IMR memory map or are modifying the IMR code and want to | |
333 | test your changes. | |
334 | ||
335 | If unsure say N here. | |
336 | ||
e97131a8 IM |
337 | config X86_DEBUG_FPU |
338 | bool "Debug the x86 FPU code" | |
339 | depends on DEBUG_KERNEL | |
340 | default y | |
341 | ---help--- | |
342 | If this option is enabled then there will be extra sanity | |
343 | checks and (boot time) debug printouts added to the kernel. | |
344 | This debugging adds some small amount of runtime overhead | |
345 | to the kernel. | |
346 | ||
347 | If unsure, say N. | |
348 | ||
956079e0 SP |
349 | config PUNIT_ATOM_DEBUG |
350 | tristate "ATOM Punit debug driver" | |
351 | select DEBUG_FS | |
352 | select IOSF_MBI | |
353 | ---help--- | |
354 | This is a debug driver, which gets the power states | |
355 | of all Punit North Complex devices. The power states of | |
356 | each device is exposed as part of the debugfs interface. | |
357 | The current power state can be read from | |
358 | /sys/kernel/debug/punit_atom/dev_power_state | |
359 | ||
c9af1e33 | 360 | endmenu |