3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config X86_VERBOSE_BOOTUP
9 bool "Enable verbose x86 bootup info messages"
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.
17 bool "Early printk" if EXPERT
20 Write kernel log output directly into the VGA buffer or to a serial
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.
29 config EARLY_PRINTK_DBGP
30 bool "Early printk via EHCI debug port"
31 depends on EARLY_PRINTK && PCI
33 Write kernel log output directly into the EHCI debug port.
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.
41 config EARLY_PRINTK_EFI
42 bool "Early printk via the EFI framebuffer"
43 depends on EFI && EARLY_PRINTK
46 Write kernel log output directly into the EFI framebuffer.
48 This is useful for kernel debugging when your machine crashes very
49 early before the console code is initialized.
51 config X86_PTDUMP_CORE
55 tristate "Export kernel pagetable layout to userspace via debugfs"
56 depends on DEBUG_KERNEL
58 select X86_PTDUMP_CORE
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
68 bool "Dump the EFI pagetable"
70 select X86_PTDUMP_CORE
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
77 config DEBUG_RODATA_TEST
78 bool "Testcase for the marking rodata read-only"
81 This option enables a testcase for the setting rodata read-only
82 as well as for the change_page_attr() infrastructure.
86 bool "Warn on W+X mappings at boot"
87 select X86_PTDUMP_CORE
89 Generate a warning if any W+X mappings are found at boot.
91 This is useful for discovering cases where the kernel is leaving
92 W+X mappings after applying NX, as such mappings are a security risk.
94 Look for a message in dmesg output like this:
96 x86/mm: Checked W+X mappings: passed, no W+X pages found.
98 or like this, if the check failed:
100 x86/mm: Checked W+X mappings: FAILED, <N> W+X pages found.
102 Note that even if the check fails, your kernel is possibly
103 still fine, as W+X mappings are not a security hole in
104 themselves, what they do is that they make the exploitation
105 of other unfixed kernel bugs easier.
107 There is no runtime or memory usage effect of this option
108 once the kernel has booted up - it's a one time check.
110 If in doubt, say "Y".
112 config DEBUG_SET_MODULE_RONX
113 bool "Set loadable kernel module data as NX and text as RO"
116 This option helps catch unintended modifications to loadable
117 kernel module's text and read-only data. It also prevents execution
118 of module data. Such protection may interfere with run-time code
119 patching and dynamic kernel tracing - and they might also protect
120 against certain classes of kernel exploits.
121 If in doubt, say "N".
125 bool "Enable doublefault exception handler" if EXPERT
127 This option allows trapping of rare doublefault exceptions that
128 would otherwise cause a system to silently reboot. Disabling this
129 option saves about 4k and might cause you much additional grey
132 config DEBUG_TLBFLUSH
133 bool "Set upper limit of TLB entries to flush one-by-one"
134 depends on DEBUG_KERNEL
139 This option allows the user to tune the amount of TLB entries the
140 kernel flushes one-by-one instead of doing a full TLB flush. In
141 certain situations, the former is cheaper. This is controlled by the
142 tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
143 to -1, the code flushes the whole TLB unconditionally. Otherwise,
144 for positive values of it, the kernel will use single TLB entry
145 invalidating instructions according to the following formula:
147 flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
149 If in doubt, say "N".
152 bool "Enable IOMMU debugging"
153 depends on GART_IOMMU && DEBUG_KERNEL
156 Force the IOMMU to on even when you have less than 4GB of
157 memory and add debugging code. On overflow always panic. And
158 allow to enable IOMMU leak tracing. Can be disabled at boot
159 time with iommu=noforce. This will also enable scatter gather
160 list merging. Currently not recommended for production
161 code. When you use it make sure you have a big enough
162 IOMMU/AGP aperture. Most of the options enabled by this can
163 be set more finegrained using the iommu= command line
164 options. See Documentation/x86/x86_64/boot-options.txt for more
168 bool "Enable IOMMU stress-test mode"
170 This option disables various optimizations in IOMMU related
171 code to do real stress testing of the IOMMU code. This option
172 will cause a performance drop and should only be enabled for
176 bool "IOMMU leak tracing"
177 depends on IOMMU_DEBUG && DMA_API_DEBUG
179 Add a simple leak tracer to the IOMMU code. This is useful when you
180 are debugging a buggy device driver that leaks IOMMU mappings.
182 config HAVE_MMIOTRACE_SUPPORT
185 config X86_DECODER_SELFTEST
186 bool "x86 instruction decoder selftest"
187 depends on DEBUG_KERNEL && KPROBES
188 depends on !COMPILE_TEST
190 Perform x86 instruction decoder selftests at build time.
191 This option is useful for checking the sanity of x86 instruction
199 config IO_DELAY_TYPE_0X80
203 config IO_DELAY_TYPE_0XED
207 config IO_DELAY_TYPE_UDELAY
211 config IO_DELAY_TYPE_NONE
216 prompt "IO delay type"
217 default IO_DELAY_0X80
220 bool "port 0x80 based port-IO delay [recommended]"
222 This is the traditional Linux IO delay used for in/out_p.
223 It is the most tested hence safest selection here.
226 bool "port 0xed based port-IO delay"
228 Use port 0xed as the IO delay. This frees up port 0x80 which is
229 often used as a hardware-debug port.
231 config IO_DELAY_UDELAY
232 bool "udelay based port-IO delay"
234 Use udelay(2) as the IO delay method. This provides the delay
235 while not having any side-effect on the IO port space.
238 bool "no port-IO delay"
240 No port-IO delay. Will break on old boxes that require port-IO
241 delay for certain operations. Should work on most new machines.
246 config DEFAULT_IO_DELAY_TYPE
248 default IO_DELAY_TYPE_0X80
252 config DEFAULT_IO_DELAY_TYPE
254 default IO_DELAY_TYPE_0XED
258 config DEFAULT_IO_DELAY_TYPE
260 default IO_DELAY_TYPE_UDELAY
264 config DEFAULT_IO_DELAY_TYPE
266 default IO_DELAY_TYPE_NONE
269 config DEBUG_BOOT_PARAMS
270 bool "Debug boot parameters"
271 depends on DEBUG_KERNEL
274 This option will cause struct boot_params to be exported via debugfs.
277 bool "CPA self-test code"
278 depends on DEBUG_KERNEL
280 Do change_page_attr() self-tests every 30 seconds.
282 config OPTIMIZE_INLINING
283 bool "Allow gcc to uninline functions marked 'inline'"
285 This option determines if the kernel forces gcc to inline the functions
286 developers have marked 'inline'. Doing so takes away freedom from gcc to
287 do what it thinks is best, which is desirable for the gcc 3.x series of
288 compilers. The gcc 4.x series have a rewritten inlining algorithm and
289 enabling this option will generate a smaller kernel there. Hopefully
290 this algorithm is so good that allowing gcc 4.x and above to make the
291 decision will become the default in the future. Until then this option
292 is there to test gcc for this.
297 bool "Debug low-level entry code"
298 depends on DEBUG_KERNEL
300 This option enables sanity checks in x86's low-level entry code.
301 Some of these sanity checks may slow down kernel entries and
302 exits or otherwise impact performance.
304 This is currently used to help test NMI code.
308 config DEBUG_NMI_SELFTEST
310 depends on DEBUG_KERNEL && X86_LOCAL_APIC
312 Enabling this option turns on a quick NMI selftest to verify
313 that the NMI behaves correctly.
315 This might help diagnose strange hangs that rely on NMI to
320 config DEBUG_IMR_SELFTEST
321 bool "Isolated Memory Region self test"
325 This option enables automated sanity testing of the IMR code.
326 Some simple tests are run to verify IMR bounds checking, alignment
327 and overlapping. This option is really only useful if you are
328 debugging an IMR memory map or are modifying the IMR code and want to
331 If unsure say N here.
334 bool "Debug the x86 FPU code"
335 depends on DEBUG_KERNEL
338 If this option is enabled then there will be extra sanity
339 checks and (boot time) debug printouts added to the kernel.
340 This debugging adds some small amount of runtime overhead
345 config PUNIT_ATOM_DEBUG
346 tristate "ATOM Punit debug driver"
350 This is a debug driver, which gets the power states
351 of all Punit North Complex devices. The power states of
352 each device is exposed as part of the debugfs interface.
353 The current power state can be read from
354 /sys/kernel/debug/punit_atom/dev_power_state