3 config TRACE_IRQFLAGS_SUPPORT
6 source "lib/Kconfig.debug"
8 config NONPROMISC_DEVMEM
9 bool "Disable promiscuous /dev/mem"
11 The /dev/mem file by default only allows userspace access to PCI
12 space and the BIOS code and data regions. This is sufficient for
13 dosemu and X and all common users of /dev/mem. With this config
14 option, you allow userspace access to all of memory, including
15 kernel and userspace memory. Accidental access to this is
16 obviously disasterous, but specific access can be used by people
20 bool "Early printk" if EMBEDDED
23 Write kernel log output directly into the VGA buffer or to a serial
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
29 with klogd/syslogd or the X server. You should normally N here,
30 unless you want to debug such a crash.
32 config DEBUG_STACKOVERFLOW
33 bool "Check for stack overflows"
34 depends on DEBUG_KERNEL
36 This option will cause messages to be printed if free stack space
37 drops below a certain limit.
39 config DEBUG_STACK_USAGE
40 bool "Stack utilization instrumentation"
41 depends on DEBUG_KERNEL
43 Enables the display of the minimum amount of free stack which each
44 task has ever had available in the sysrq-T and sysrq-P debug output.
46 This option will slow down process creation somewhat.
48 config DEBUG_PAGEALLOC
49 bool "Debug page memory allocations"
50 depends on DEBUG_KERNEL
52 Unmap pages from the kernel linear mapping after free_pages().
53 This results in a large slowdown, but helps to find certain types
54 of memory corruptions.
56 config DEBUG_PER_CPU_MAPS
57 bool "Debug access to per_cpu maps"
58 depends on DEBUG_KERNEL
62 Say Y to verify that the per_cpu map being accessed has
63 been setup. Adds a fair amount of code to kernel memory
64 and decreases performance.
69 bool "Export kernel pagetable layout to userspace via debugfs"
70 depends on DEBUG_KERNEL
73 Say Y here if you want to show the kernel pagetable layout in a
74 debugfs file. This information is only useful for kernel developers
75 who are working in architecture specific areas of the kernel.
76 It is probably not a good idea to enable this feature in a production
81 bool "Write protect kernel read-only data structures"
83 depends on DEBUG_KERNEL
85 Mark the kernel read-only data as write-protected in the pagetables,
86 in order to catch accidental (and incorrect) writes to such const
87 data. This is recommended so that we can catch kernel bugs sooner.
91 bool "Enable gbpages-mapped kernel pagetables"
92 depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
94 Enable gigabyte pages support (if the CPU supports it). This can
95 improve the kernel's performance a tiny bit by reducing TLB
98 This is experimental code.
100 If in doubt, say "N".
102 config DEBUG_RODATA_TEST
103 bool "Testcase for the DEBUG_RODATA feature"
104 depends on DEBUG_RODATA
106 This option enables a testcase for the DEBUG_RODATA
107 feature as well as for the change_page_attr() infrastructure.
111 tristate "Testcase for the NX non-executable stack feature"
112 depends on DEBUG_KERNEL && m
114 This option enables a testcase for the CPU NX capability
115 and the software setup of this feature.
119 bool "Use 4Kb for kernel stacks instead of 8Kb"
122 If you say Y here the kernel will use a 4Kb stacksize for the
123 kernel stack attached to each process/thread. This facilitates
124 running more threads on a system and also reduces the pressure
125 on the VM subsystem for higher order allocations. This option
126 will also use IRQ stacks to compensate for the reduced stackspace.
128 config X86_FIND_SMP_CONFIG
130 depends on X86_LOCAL_APIC || X86_VOYAGER
135 depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
139 bool "Enable doublefault exception handler" if EMBEDDED
142 This option allows trapping of rare doublefault exceptions that
143 would otherwise cause a system to silently reboot. Disabling this
144 option saves about 4k and might cause you much additional grey
148 bool "Enable IOMMU debugging"
149 depends on GART_IOMMU && DEBUG_KERNEL
152 Force the IOMMU to on even when you have less than 4GB of
153 memory and add debugging code. On overflow always panic. And
154 allow to enable IOMMU leak tracing. Can be disabled at boot
155 time with iommu=noforce. This will also enable scatter gather
156 list merging. Currently not recommended for production
157 code. When you use it make sure you have a big enough
158 IOMMU/AGP aperture. Most of the options enabled by this can
159 be set more finegrained using the iommu= command line
160 options. See Documentation/x86_64/boot-options.txt for more
164 bool "IOMMU leak tracing"
165 depends on DEBUG_KERNEL
166 depends on IOMMU_DEBUG
168 Add a simple leak tracer to the IOMMU code. This is useful when you
169 are debugging a buggy device driver that leaks IOMMU mappings.
171 config MMIOTRACE_HOOKS
175 bool "Memory mapped IO tracing"
176 depends on DEBUG_KERNEL
178 select MMIOTRACE_HOOKS
181 Mmiotrace traces Memory Mapped I/O access and is meant for
182 debugging and reverse engineering. It is called from the ioremap
183 implementation and works via page faults. A user space program is
184 required to collect the MMIO data from debugfs files.
185 Tracing is disabled by default and can be enabled from a debugfs
188 See http://nouveau.freedesktop.org/wiki/MmioTrace
189 If you are not helping to develop drivers, say N.
191 config MMIOTRACE_TEST
192 tristate "Test module for mmiotrace"
193 depends on MMIOTRACE && m
195 This is a dumb module for testing mmiotrace. It is very dangerous
196 as it will write garbage to IO memory starting at a given address.
197 However, it should be safe to use on e.g. unused portion of VRAM.
199 Say N, unless you absolutely know what you are doing.
205 config IO_DELAY_TYPE_0X80
209 config IO_DELAY_TYPE_0XED
213 config IO_DELAY_TYPE_UDELAY
217 config IO_DELAY_TYPE_NONE
222 prompt "IO delay type"
223 default IO_DELAY_0X80
226 bool "port 0x80 based port-IO delay [recommended]"
228 This is the traditional Linux IO delay used for in/out_p.
229 It is the most tested hence safest selection here.
232 bool "port 0xed based port-IO delay"
234 Use port 0xed as the IO delay. This frees up port 0x80 which is
235 often used as a hardware-debug port.
237 config IO_DELAY_UDELAY
238 bool "udelay based port-IO delay"
240 Use udelay(2) as the IO delay method. This provides the delay
241 while not having any side-effect on the IO port space.
244 bool "no port-IO delay"
246 No port-IO delay. Will break on old boxes that require port-IO
247 delay for certain operations. Should work on most new machines.
252 config DEFAULT_IO_DELAY_TYPE
254 default IO_DELAY_TYPE_0X80
258 config DEFAULT_IO_DELAY_TYPE
260 default IO_DELAY_TYPE_0XED
264 config DEFAULT_IO_DELAY_TYPE
266 default IO_DELAY_TYPE_UDELAY
270 config DEFAULT_IO_DELAY_TYPE
272 default IO_DELAY_TYPE_NONE
275 config DEBUG_BOOT_PARAMS
276 bool "Debug boot parameters"
277 depends on DEBUG_KERNEL
280 This option will cause struct boot_params to be exported via debugfs.
283 bool "CPA self-test code"
284 depends on DEBUG_KERNEL
286 Do change_page_attr() self-tests every 30 seconds.
288 config OPTIMIZE_INLINING
289 bool "Allow gcc to uninline functions marked 'inline'"
292 This option determines if the kernel forces gcc to inline the functions
293 developers have marked 'inline'. Doing so takes away freedom from gcc to
294 do what it thinks is best, which is desirable for the gcc 3.x series of
295 compilers. The gcc 4.x series have a rewritten inlining algorithm and
296 disabling this option will generate a smaller kernel there. Hopefully
297 this algorithm is so good that allowing gcc4 to make the decision can
298 become the default in the future, until then this option is there to