3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config NONPROMISC_DEVMEM
9 bool "Filter access to /dev/mem"
11 If this option is left off, you allow userspace access to all
12 of memory, including kernel and userspace memory. Accidental
13 access to this is obviously disastrous, but specific access can
14 be used by people debugging the kernel.
16 If this option is switched on, the /dev/mem file only allows
17 userspace access to PCI space and the BIOS code and data regions.
18 This is sufficient for dosemu and X and all common users of
23 config X86_VERBOSE_BOOTUP
24 bool "Enable verbose x86 bootup info messages"
27 Enables the informational output from the decompression stage
28 (e.g. bzImage) of the boot. If you disable this you will still
29 see errors. Disable this if you want silent bootup.
32 bool "Early printk" if EMBEDDED
35 Write kernel log output directly into the VGA buffer or to a serial
38 This is useful for kernel debugging when your machine crashes very
39 early before the console code is initialized. For normal operation
40 it is not recommended because it looks ugly and doesn't cooperate
41 with klogd/syslogd or the X server. You should normally N here,
42 unless you want to debug such a crash.
44 config DEBUG_STACKOVERFLOW
45 bool "Check for stack overflows"
46 depends on DEBUG_KERNEL
48 This option will cause messages to be printed if free stack space
49 drops below a certain limit.
51 config DEBUG_STACK_USAGE
52 bool "Stack utilization instrumentation"
53 depends on DEBUG_KERNEL
55 Enables the display of the minimum amount of free stack which each
56 task has ever had available in the sysrq-T and sysrq-P debug output.
58 This option will slow down process creation somewhat.
60 config DEBUG_PAGEALLOC
61 bool "Debug page memory allocations"
62 depends on DEBUG_KERNEL
64 Unmap pages from the kernel linear mapping after free_pages().
65 This results in a large slowdown, but helps to find certain types
66 of memory corruptions.
68 config DEBUG_PER_CPU_MAPS
69 bool "Debug access to per_cpu maps"
70 depends on DEBUG_KERNEL
74 Say Y to verify that the per_cpu map being accessed has
75 been setup. Adds a fair amount of code to kernel memory
76 and decreases performance.
81 bool "Export kernel pagetable layout to userspace via debugfs"
82 depends on DEBUG_KERNEL
85 Say Y here if you want to show the kernel pagetable layout in a
86 debugfs file. This information is only useful for kernel developers
87 who are working in architecture specific areas of the kernel.
88 It is probably not a good idea to enable this feature in a production
93 bool "Write protect kernel read-only data structures"
95 depends on DEBUG_KERNEL
97 Mark the kernel read-only data as write-protected in the pagetables,
98 in order to catch accidental (and incorrect) writes to such const
99 data. This is recommended so that we can catch kernel bugs sooner.
100 If in doubt, say "Y".
102 config DIRECT_GBPAGES
103 bool "Enable gbpages-mapped kernel pagetables"
104 depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
106 Enable gigabyte pages support (if the CPU supports it). This can
107 improve the kernel's performance a tiny bit by reducing TLB
110 This is experimental code.
112 If in doubt, say "N".
114 config DEBUG_RODATA_TEST
115 bool "Testcase for the DEBUG_RODATA feature"
116 depends on DEBUG_RODATA
118 This option enables a testcase for the DEBUG_RODATA
119 feature as well as for the change_page_attr() infrastructure.
123 tristate "Testcase for the NX non-executable stack feature"
124 depends on DEBUG_KERNEL && m
126 This option enables a testcase for the CPU NX capability
127 and the software setup of this feature.
131 bool "Use 4Kb for kernel stacks instead of 8Kb"
134 If you say Y here the kernel will use a 4Kb stacksize for the
135 kernel stack attached to each process/thread. This facilitates
136 running more threads on a system and also reduces the pressure
137 on the VM subsystem for higher order allocations. This option
138 will also use IRQ stacks to compensate for the reduced stackspace.
140 config X86_FIND_SMP_CONFIG
142 depends on X86_LOCAL_APIC || X86_VOYAGER
147 depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
151 bool "Enable doublefault exception handler" if EMBEDDED
154 This option allows trapping of rare doublefault exceptions that
155 would otherwise cause a system to silently reboot. Disabling this
156 option saves about 4k and might cause you much additional grey
160 bool "Enable IOMMU debugging"
161 depends on GART_IOMMU && DEBUG_KERNEL
164 Force the IOMMU to on even when you have less than 4GB of
165 memory and add debugging code. On overflow always panic. And
166 allow to enable IOMMU leak tracing. Can be disabled at boot
167 time with iommu=noforce. This will also enable scatter gather
168 list merging. Currently not recommended for production
169 code. When you use it make sure you have a big enough
170 IOMMU/AGP aperture. Most of the options enabled by this can
171 be set more finegrained using the iommu= command line
172 options. See Documentation/x86_64/boot-options.txt for more
176 bool "IOMMU leak tracing"
177 depends on DEBUG_KERNEL
178 depends on IOMMU_DEBUG
180 Add a simple leak tracer to the IOMMU code. This is useful when you
181 are debugging a buggy device driver that leaks IOMMU mappings.
187 config IO_DELAY_TYPE_0X80
191 config IO_DELAY_TYPE_0XED
195 config IO_DELAY_TYPE_UDELAY
199 config IO_DELAY_TYPE_NONE
204 prompt "IO delay type"
205 default IO_DELAY_0X80
208 bool "port 0x80 based port-IO delay [recommended]"
210 This is the traditional Linux IO delay used for in/out_p.
211 It is the most tested hence safest selection here.
214 bool "port 0xed based port-IO delay"
216 Use port 0xed as the IO delay. This frees up port 0x80 which is
217 often used as a hardware-debug port.
219 config IO_DELAY_UDELAY
220 bool "udelay based port-IO delay"
222 Use udelay(2) as the IO delay method. This provides the delay
223 while not having any side-effect on the IO port space.
226 bool "no port-IO delay"
228 No port-IO delay. Will break on old boxes that require port-IO
229 delay for certain operations. Should work on most new machines.
234 config DEFAULT_IO_DELAY_TYPE
236 default IO_DELAY_TYPE_0X80
240 config DEFAULT_IO_DELAY_TYPE
242 default IO_DELAY_TYPE_0XED
246 config DEFAULT_IO_DELAY_TYPE
248 default IO_DELAY_TYPE_UDELAY
252 config DEFAULT_IO_DELAY_TYPE
254 default IO_DELAY_TYPE_NONE
257 config DEBUG_BOOT_PARAMS
258 bool "Debug boot parameters"
259 depends on DEBUG_KERNEL
262 This option will cause struct boot_params to be exported via debugfs.
265 bool "CPA self-test code"
266 depends on DEBUG_KERNEL
268 Do change_page_attr() self-tests every 30 seconds.
270 config OPTIMIZE_INLINING
271 bool "Allow gcc to uninline functions marked 'inline'"
274 This option determines if the kernel forces gcc to inline the functions
275 developers have marked 'inline'. Doing so takes away freedom from gcc to
276 do what it thinks is best, which is desirable for the gcc 3.x series of
277 compilers. The gcc 4.x series have a rewritten inlining algorithm and
278 disabling this option will generate a smaller kernel there. Hopefully
279 this algorithm is so good that allowing gcc4 to make the decision can
280 become the default in the future, until then this option is there to