Commit | Line | Data |
---|---|---|
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 | ||
6bcb13b3 BC |
8 | config X86_VERBOSE_BOOTUP |
9 | bool "Enable verbose x86 bootup info messages" | |
10 | default y | |
8f9ca475 | 11 | ---help--- |
6bcb13b3 BC |
12 | Enables the informational output from the decompression stage |
13 | (e.g. bzImage) of the boot. If you disable this you will still | |
14 | see errors. Disable this if you want silent bootup. | |
15 | ||
1da177e4 | 16 | config EARLY_PRINTK |
6a108a14 | 17 | bool "Early printk" if EXPERT |
1da177e4 | 18 | default y |
8f9ca475 | 19 | ---help--- |
1da177e4 LT |
20 | Write kernel log output directly into the VGA buffer or to a serial |
21 | port. | |
22 | ||
23 | This is useful for kernel debugging when your machine crashes very | |
24 | early before the console code is initialized. For normal operation | |
25 | it is not recommended because it looks ugly and doesn't cooperate | |
26 | with klogd/syslogd or the X server. You should normally N here, | |
27 | unless you want to debug such a crash. | |
28 | ||
5c05917e YL |
29 | config EARLY_PRINTK_DBGP |
30 | bool "Early printk via EHCI debug port" | |
9749986a | 31 | depends on EARLY_PRINTK && PCI |
8f9ca475 | 32 | ---help--- |
5c05917e YL |
33 | Write kernel log output directly into the EHCI debug port. |
34 | ||
35 | This is useful for kernel debugging when your machine crashes very | |
36 | early before the console code is initialized. For normal operation | |
37 | it is not recommended because it looks ugly and doesn't cooperate | |
38 | with klogd/syslogd or the X server. You should normally N here, | |
39 | unless you want to debug such a crash. You need usb debug device. | |
40 | ||
72548e83 MF |
41 | config EARLY_PRINTK_EFI |
42 | bool "Early printk via the EFI framebuffer" | |
43 | depends on EFI && EARLY_PRINTK | |
44 | select FONT_SUPPORT | |
45 | ---help--- | |
46 | Write kernel log output directly into the EFI framebuffer. | |
47 | ||
48 | This is useful for kernel debugging when your machine crashes very | |
49 | early before the console code is initialized. | |
50 | ||
e1a58320 SS |
51 | config X86_PTDUMP_CORE |
52 | def_bool n | |
53 | ||
926e5392 | 54 | config X86_PTDUMP |
8609d1b5 | 55 | tristate "Export kernel pagetable layout to userspace via debugfs" |
fe770bf0 | 56 | depends on DEBUG_KERNEL |
926e5392 | 57 | select DEBUG_FS |
e1a58320 | 58 | select X86_PTDUMP_CORE |
8f9ca475 | 59 | ---help--- |
926e5392 AV |
60 | Say Y here if you want to show the kernel pagetable layout in a |
61 | debugfs file. This information is only useful for kernel developers | |
62 | who are working in architecture specific areas of the kernel. | |
63 | It is probably not a good idea to enable this feature in a production | |
64 | kernel. | |
65 | If in doubt, say "N" | |
66 | ||
11cc8512 BP |
67 | config EFI_PGT_DUMP |
68 | bool "Dump the EFI pagetable" | |
e1a58320 SS |
69 | depends on EFI |
70 | select X86_PTDUMP_CORE | |
11cc8512 BP |
71 | ---help--- |
72 | Enable this if you want to dump the EFI page table before | |
73 | enabling virtual mode. This can be used to debug miscellaneous | |
74 | issues with the mapping of the EFI runtime regions into that | |
75 | table. | |
76 | ||
63aaf308 AV |
77 | config DEBUG_RODATA |
78 | bool "Write protect kernel read-only data structures" | |
11201e60 | 79 | default y |
63aaf308 | 80 | depends on DEBUG_KERNEL |
8f9ca475 | 81 | ---help--- |
63aaf308 AV |
82 | Mark the kernel read-only data as write-protected in the pagetables, |
83 | in order to catch accidental (and incorrect) writes to such const | |
11201e60 IM |
84 | data. This is recommended so that we can catch kernel bugs sooner. |
85 | If in doubt, say "Y". | |
63aaf308 | 86 | |
aba8391f IM |
87 | config DEBUG_RODATA_TEST |
88 | bool "Testcase for the DEBUG_RODATA feature" | |
89 | depends on DEBUG_RODATA | |
72370f2a | 90 | default y |
8f9ca475 | 91 | ---help--- |
aba8391f IM |
92 | This option enables a testcase for the DEBUG_RODATA |
93 | feature as well as for the change_page_attr() infrastructure. | |
94 | If in doubt, say "N" | |
95 | ||
e1a58320 SS |
96 | config DEBUG_WX |
97 | bool "Warn on W+X mappings at boot" | |
98 | depends on DEBUG_RODATA | |
e1a58320 SS |
99 | select X86_PTDUMP_CORE |
100 | ---help--- | |
101 | Generate a warning if any W+X mappings are found at boot. | |
102 | ||
103 | This is useful for discovering cases where the kernel is leaving | |
104 | W+X mappings after applying NX, as such mappings are a security risk. | |
105 | ||
106 | Look for a message in dmesg output like this: | |
107 | ||
108 | x86/mm: Checked W+X mappings: passed, no W+X pages found. | |
109 | ||
110 | or like this, if the check failed: | |
111 | ||
112 | x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found. | |
113 | ||
114 | Note that even if the check fails, your kernel is possibly | |
115 | still fine, as W+X mappings are not a security hole in | |
116 | themselves, what they do is that they make the exploitation | |
117 | of other unfixed kernel bugs easier. | |
118 | ||
119 | There is no runtime or memory usage effect of this option | |
120 | once the kernel has booted up - it's a one time check. | |
121 | ||
122 | If in doubt, say "Y". | |
123 | ||
84e1c6bb | 124 | config DEBUG_SET_MODULE_RONX |
125 | bool "Set loadable kernel module data as NX and text as RO" | |
126 | depends on MODULES | |
127 | ---help--- | |
128 | This option helps catch unintended modifications to loadable | |
129 | kernel module's text and read-only data. It also prevents execution | |
130 | of module data. Such protection may interfere with run-time code | |
131 | patching and dynamic kernel tracing - and they might also protect | |
132 | against certain classes of kernel exploits. | |
133 | If in doubt, say "N". | |
134 | ||
aba8391f IM |
135 | config DEBUG_NX_TEST |
136 | tristate "Testcase for the NX non-executable stack feature" | |
137 | depends on DEBUG_KERNEL && m | |
8f9ca475 | 138 | ---help--- |
aba8391f IM |
139 | This option enables a testcase for the CPU NX capability |
140 | and the software setup of this feature. | |
141 | If in doubt, say "N" | |
142 | ||
102e41fd AK |
143 | config DOUBLEFAULT |
144 | default y | |
6a108a14 | 145 | bool "Enable doublefault exception handler" if EXPERT |
8f9ca475 | 146 | ---help--- |
d013a27c RD |
147 | This option allows trapping of rare doublefault exceptions that |
148 | would otherwise cause a system to silently reboot. Disabling this | |
149 | option saves about 4k and might cause you much additional grey | |
150 | hair. | |
151 | ||
3df3212f AS |
152 | config DEBUG_TLBFLUSH |
153 | bool "Set upper limit of TLB entries to flush one-by-one" | |
cd69aa6b | 154 | depends on DEBUG_KERNEL |
3df3212f AS |
155 | ---help--- |
156 | ||
157 | X86-only for now. | |
158 | ||
159 | This option allows the user to tune the amount of TLB entries the | |
160 | kernel flushes one-by-one instead of doing a full TLB flush. In | |
161 | certain situations, the former is cheaper. This is controlled by the | |
162 | tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it | |
163 | to -1, the code flushes the whole TLB unconditionally. Otherwise, | |
164 | for positive values of it, the kernel will use single TLB entry | |
165 | invalidating instructions according to the following formula: | |
166 | ||
167 | flush_entries <= active_tlb_entries / 2^tlb_flushall_shift | |
168 | ||
169 | If in doubt, say "N". | |
170 | ||
d013a27c RD |
171 | config IOMMU_DEBUG |
172 | bool "Enable IOMMU debugging" | |
966396d3 | 173 | depends on GART_IOMMU && DEBUG_KERNEL |
d013a27c | 174 | depends on X86_64 |
8f9ca475 | 175 | ---help--- |
d013a27c RD |
176 | Force the IOMMU to on even when you have less than 4GB of |
177 | memory and add debugging code. On overflow always panic. And | |
178 | allow to enable IOMMU leak tracing. Can be disabled at boot | |
179 | time with iommu=noforce. This will also enable scatter gather | |
180 | list merging. Currently not recommended for production | |
181 | code. When you use it make sure you have a big enough | |
182 | IOMMU/AGP aperture. Most of the options enabled by this can | |
183 | be set more finegrained using the iommu= command line | |
395cf969 | 184 | options. See Documentation/x86/x86_64/boot-options.txt for more |
d013a27c RD |
185 | details. |
186 | ||
2be69c79 JR |
187 | config IOMMU_STRESS |
188 | bool "Enable IOMMU stress-test mode" | |
189 | ---help--- | |
190 | This option disables various optimizations in IOMMU related | |
191 | code to do real stress testing of the IOMMU code. This option | |
192 | will cause a performance drop and should only be enabled for | |
193 | testing. | |
194 | ||
d013a27c RD |
195 | config IOMMU_LEAK |
196 | bool "IOMMU leak tracing" | |
19c1a6f5 | 197 | depends on IOMMU_DEBUG && DMA_API_DEBUG |
8f9ca475 | 198 | ---help--- |
d013a27c RD |
199 | Add a simple leak tracer to the IOMMU code. This is useful when you |
200 | are debugging a buggy device driver that leaks IOMMU mappings. | |
201 | ||
6bc5c366 PP |
202 | config HAVE_MMIOTRACE_SUPPORT |
203 | def_bool y | |
8b7d89d0 | 204 | |
ca0e9bad | 205 | config X86_DECODER_SELFTEST |
cbe5c34c OH |
206 | bool "x86 instruction decoder selftest" |
207 | depends on DEBUG_KERNEL && KPROBES | |
f8f20234 | 208 | depends on !COMPILE_TEST |
ca0e9bad MH |
209 | ---help--- |
210 | Perform x86 instruction decoder selftests at build time. | |
211 | This option is useful for checking the sanity of x86 instruction | |
212 | decoder code. | |
213 | If unsure, say "N". | |
214 | ||
6e7c4025 IM |
215 | # |
216 | # IO delay types: | |
217 | # | |
218 | ||
219 | config IO_DELAY_TYPE_0X80 | |
220 | int | |
221 | default "0" | |
222 | ||
223 | config IO_DELAY_TYPE_0XED | |
224 | int | |
225 | default "1" | |
226 | ||
227 | config IO_DELAY_TYPE_UDELAY | |
228 | int | |
229 | default "2" | |
230 | ||
231 | config IO_DELAY_TYPE_NONE | |
232 | int | |
233 | default "3" | |
234 | ||
235 | choice | |
236 | prompt "IO delay type" | |
fd59e9e9 | 237 | default IO_DELAY_0X80 |
6e7c4025 IM |
238 | |
239 | config IO_DELAY_0X80 | |
240 | bool "port 0x80 based port-IO delay [recommended]" | |
8f9ca475 | 241 | ---help--- |
6e7c4025 IM |
242 | This is the traditional Linux IO delay used for in/out_p. |
243 | It is the most tested hence safest selection here. | |
244 | ||
245 | config IO_DELAY_0XED | |
246 | bool "port 0xed based port-IO delay" | |
8f9ca475 | 247 | ---help--- |
6e7c4025 IM |
248 | Use port 0xed as the IO delay. This frees up port 0x80 which is |
249 | often used as a hardware-debug port. | |
250 | ||
251 | config IO_DELAY_UDELAY | |
252 | bool "udelay based port-IO delay" | |
8f9ca475 | 253 | ---help--- |
6e7c4025 IM |
254 | Use udelay(2) as the IO delay method. This provides the delay |
255 | while not having any side-effect on the IO port space. | |
256 | ||
257 | config IO_DELAY_NONE | |
258 | bool "no port-IO delay" | |
8f9ca475 | 259 | ---help--- |
6e7c4025 IM |
260 | No port-IO delay. Will break on old boxes that require port-IO |
261 | delay for certain operations. Should work on most new machines. | |
262 | ||
263 | endchoice | |
264 | ||
265 | if IO_DELAY_0X80 | |
266 | config DEFAULT_IO_DELAY_TYPE | |
267 | int | |
268 | default IO_DELAY_TYPE_0X80 | |
269 | endif | |
270 | ||
271 | if IO_DELAY_0XED | |
272 | config DEFAULT_IO_DELAY_TYPE | |
273 | int | |
274 | default IO_DELAY_TYPE_0XED | |
275 | endif | |
276 | ||
277 | if IO_DELAY_UDELAY | |
278 | config DEFAULT_IO_DELAY_TYPE | |
279 | int | |
280 | default IO_DELAY_TYPE_UDELAY | |
281 | endif | |
282 | ||
283 | if IO_DELAY_NONE | |
284 | config DEFAULT_IO_DELAY_TYPE | |
285 | int | |
286 | default IO_DELAY_TYPE_NONE | |
287 | endif | |
b02aae9c | 288 | |
6d7d7433 HY |
289 | config DEBUG_BOOT_PARAMS |
290 | bool "Debug boot parameters" | |
291 | depends on DEBUG_KERNEL | |
292 | depends on DEBUG_FS | |
8f9ca475 | 293 | ---help--- |
6d7d7433 HY |
294 | This option will cause struct boot_params to be exported via debugfs. |
295 | ||
0c42f392 | 296 | config CPA_DEBUG |
971a52d6 | 297 | bool "CPA self-test code" |
f316fe68 | 298 | depends on DEBUG_KERNEL |
8f9ca475 | 299 | ---help--- |
971a52d6 | 300 | Do change_page_attr() self-tests every 30 seconds. |
0c42f392 | 301 | |
60a3cdd0 IM |
302 | config OPTIMIZE_INLINING |
303 | bool "Allow gcc to uninline functions marked 'inline'" | |
8f9ca475 | 304 | ---help--- |
60a3cdd0 IM |
305 | This option determines if the kernel forces gcc to inline the functions |
306 | developers have marked 'inline'. Doing so takes away freedom from gcc to | |
307 | do what it thinks is best, which is desirable for the gcc 3.x series of | |
308 | compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
63fb7085 SW |
309 | enabling this option will generate a smaller kernel there. Hopefully |
310 | this algorithm is so good that allowing gcc 4.x and above to make the | |
311 | decision will become the default in the future. Until then this option | |
312 | is there to test gcc for this. | |
c9af1e33 | 313 | |
3f9b5cc0 IM |
314 | If unsure, say N. |
315 | ||
a97439aa AL |
316 | config DEBUG_ENTRY |
317 | bool "Debug low-level entry code" | |
318 | depends on DEBUG_KERNEL | |
319 | ---help--- | |
320 | This option enables sanity checks in x86's low-level entry code. | |
321 | Some of these sanity checks may slow down kernel entries and | |
322 | exits or otherwise impact performance. | |
323 | ||
324 | This is currently used to help test NMI code. | |
325 | ||
326 | If unsure, say N. | |
327 | ||
99e8b9ca DZ |
328 | config DEBUG_NMI_SELFTEST |
329 | bool "NMI Selftest" | |
4f941c57 | 330 | depends on DEBUG_KERNEL && X86_LOCAL_APIC |
99e8b9ca DZ |
331 | ---help--- |
332 | Enabling this option turns on a quick NMI selftest to verify | |
333 | that the NMI behaves correctly. | |
334 | ||
335 | This might help diagnose strange hangs that rely on NMI to | |
336 | function properly. | |
337 | ||
338 | If unsure, say N. | |
339 | ||
28a375df BD |
340 | config DEBUG_IMR_SELFTEST |
341 | bool "Isolated Memory Region self test" | |
342 | default n | |
343 | depends on INTEL_IMR | |
344 | ---help--- | |
345 | This option enables automated sanity testing of the IMR code. | |
346 | Some simple tests are run to verify IMR bounds checking, alignment | |
347 | and overlapping. This option is really only useful if you are | |
348 | debugging an IMR memory map or are modifying the IMR code and want to | |
349 | test your changes. | |
350 | ||
351 | If unsure say N here. | |
352 | ||
5700f743 BP |
353 | config X86_DEBUG_STATIC_CPU_HAS |
354 | bool "Debug alternatives" | |
355 | depends on DEBUG_KERNEL | |
356 | ---help--- | |
357 | This option causes additional code to be generated which | |
358 | fails if static_cpu_has() is used before alternatives have | |
359 | run. | |
360 | ||
361 | If unsure, say N. | |
362 | ||
e97131a8 IM |
363 | config X86_DEBUG_FPU |
364 | bool "Debug the x86 FPU code" | |
365 | depends on DEBUG_KERNEL | |
366 | default y | |
367 | ---help--- | |
368 | If this option is enabled then there will be extra sanity | |
369 | checks and (boot time) debug printouts added to the kernel. | |
370 | This debugging adds some small amount of runtime overhead | |
371 | to the kernel. | |
372 | ||
373 | If unsure, say N. | |
374 | ||
956079e0 SP |
375 | config PUNIT_ATOM_DEBUG |
376 | tristate "ATOM Punit debug driver" | |
377 | select DEBUG_FS | |
378 | select IOSF_MBI | |
379 | ---help--- | |
380 | This is a debug driver, which gets the power states | |
381 | of all Punit North Complex devices. The power states of | |
382 | each device is exposed as part of the debugfs interface. | |
383 | The current power state can be read from | |
384 | /sys/kernel/debug/punit_atom/dev_power_state | |
385 | ||
c9af1e33 | 386 | endmenu |