1 menu "Kernel hacking"
3 source "lib/Kconfig.debug"
5 config STRICT_DEVMEM
6 bool "Filter access to /dev/mem"
7 depends on MMU
8 ---help---
9 If this option is disabled, you allow userspace (root) access to all
10 of memory, including kernel and userspace memory. Accidental
11 access to this is obviously disastrous, but specific access can
12 be used by people debugging the kernel.
14 If this option is switched on, the /dev/mem file only allows
15 userspace access to memory mapped peripherals.
17 If in doubt, say Y.
19 # RMK wants arm kernels compiled with frame pointers or stack unwinding.
20 # If you know what you are doing and are willing to live without stack
21 # traces, you can get a slightly smaller kernel by setting this option to
22 # n, but then RMK will have to kill you ;).
23 config FRAME_POINTER
24 bool
25 depends on !THUMB2_KERNEL
26 default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
27 help
28 If you say N here, the resulting kernel will be slightly smaller and
29 faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled,
30 when a problem occurs with the kernel, the information that is
31 reported is severely limited.
33 config ARM_UNWIND
34 bool "Enable stack unwinding support (EXPERIMENTAL)"
35 depends on AEABI && EXPERIMENTAL
36 default y
37 help
38 This option enables stack unwinding support in the kernel
39 using the information automatically generated by the
40 compiler. The resulting kernel image is slightly bigger but
41 the performance is not affected. Currently, this feature
42 only works with EABI compilers. If unsure say Y.
44 config OLD_MCOUNT
45 bool
46 depends on FUNCTION_TRACER && FRAME_POINTER
47 default y
49 config DEBUG_USER
50 bool "Verbose user fault messages"
51 help
52 When a user program crashes due to an exception, the kernel can
53 print a brief message explaining what the problem was. This is
54 sometimes helpful for debugging but serves no purpose on a
55 production system. Most people should say N here.
57 In addition, you need to pass user_debug=N on the kernel command
58 line to enable this feature. N consists of the sum of:
60 1 - undefined instruction events
61 2 - system calls
62 4 - invalid data aborts
63 8 - SIGSEGV faults
64 16 - SIGBUS faults
66 config DEBUG_RODATA
67 bool "Write protect kernel text section"
68 default n
69 depends on DEBUG_KERNEL && MMU
70 ---help---
71 Mark the kernel text section as write-protected in the pagetables,
72 in order to catch accidental (and incorrect) writes to such const
73 data. This will cause the size of the kernel, plus up to 4MB, to
74 be mapped as pages instead of sections, which will increase TLB
75 pressure.
76 If in doubt, say "N".
78 config DEBUG_RODATA_TEST
79 bool "Testcase for the DEBUG_RODATA feature"
80 depends on DEBUG_RODATA
81 default n
82 ---help---
83 This option enables a testcase for the DEBUG_RODATA
84 feature.
85 If in doubt, say "N"
87 # These options are only for real kernel hackers who want to get their hands dirty.
88 config DEBUG_LL
89 bool "Kernel low-level debugging functions (read help!)"
90 depends on DEBUG_KERNEL
91 help
92 Say Y here to include definitions of printascii, printch, printhex
93 in the kernel. This is helpful if you are debugging code that
94 executes before the console is initialized.
96 Note that selecting this option will limit the kernel to a single
97 UART definition, as specified below. Attempting to boot the kernel
98 image on a different platform *will not work*, so this option should
99 not be enabled for kernels that are intended to be portable.
101 choice
102 prompt "Kernel low-level debugging port"
103 depends on DEBUG_LL
105 config AT91_DEBUG_LL_DBGU0
106 bool "Kernel low-level debugging on rm9200, 9260/9g20, 9261/9g10 and 9rl"
107 depends on HAVE_AT91_DBGU0
109 config AT91_DEBUG_LL_DBGU1
110 bool "Kernel low-level debugging on 9263 and 9g45"
111 depends on HAVE_AT91_DBGU1
113 config DEBUG_CLPS711X_UART1
114 bool "Kernel low-level debugging messages via UART1"
115 depends on ARCH_CLPS711X
116 help
117 Say Y here if you want the debug print routines to direct
118 their output to the first serial port on these devices.
120 config DEBUG_CLPS711X_UART2
121 bool "Kernel low-level debugging messages via UART2"
122 depends on ARCH_CLPS711X
123 help
124 Say Y here if you want the debug print routines to direct
125 their output to the second serial port on these devices.
127 config DEBUG_DAVINCI_DA8XX_UART1
128 bool "Kernel low-level debugging on DaVinci DA8XX using UART1"
129 depends on ARCH_DAVINCI_DA8XX
130 help
131 Say Y here if you want the debug print routines to direct
132 their output to UART1 serial port on DaVinci DA8XX devices.
134 config DEBUG_DAVINCI_DA8XX_UART2
135 bool "Kernel low-level debugging on DaVinci DA8XX using UART2"
136 depends on ARCH_DAVINCI_DA8XX
137 help
138 Say Y here if you want the debug print routines to direct
139 their output to UART2 serial port on DaVinci DA8XX devices.
141 config DEBUG_DAVINCI_DMx_UART0
142 bool "Kernel low-level debugging on DaVinci DMx using UART0"
143 depends on ARCH_DAVINCI_DMx
144 help
145 Say Y here if you want the debug print routines to direct
146 their output to UART0 serial port on DaVinci DMx devices.
148 config DEBUG_DAVINCI_TNETV107X_UART1
149 bool "Kernel low-level debugging on DaVinci TNETV107x using UART1"
150 depends on ARCH_DAVINCI_TNETV107X
151 help
152 Say Y here if you want the debug print routines to direct
153 their output to UART1 serial port on DaVinci TNETV107X
154 devices.
156 config DEBUG_ZYNQ_UART0
157 bool "Kernel low-level debugging on Xilinx Zynq using UART0"
158 depends on ARCH_ZYNQ
159 help
160 Say Y here if you want the debug print routines to direct
161 their output to UART0 on the Zynq platform.
163 config DEBUG_ZYNQ_UART1
164 bool "Kernel low-level debugging on Xilinx Zynq using UART1"
165 depends on ARCH_ZYNQ
166 help
167 Say Y here if you want the debug print routines to direct
168 their output to UART1 on the Zynq platform.
170 If you have a ZC702 board and want early boot messages to
171 appear on the USB serial adaptor, select this option.
173 config DEBUG_DC21285_PORT
174 bool "Kernel low-level debugging messages via footbridge serial port"
175 depends on FOOTBRIDGE
176 help
177 Say Y here if you want the debug print routines to direct
178 their output to the serial port in the DC21285 (Footbridge).
180 config DEBUG_FOOTBRIDGE_COM1
181 bool "Kernel low-level debugging messages via footbridge 8250 at PCI COM1"
182 depends on FOOTBRIDGE
183 help
184 Say Y here if you want the debug print routines to direct
185 their output to the 8250 at PCI COM1.
187 config DEBUG_HIGHBANK_UART
188 bool "Kernel low-level debugging messages via Highbank UART"
189 depends on ARCH_HIGHBANK
190 help
191 Say Y here if you want the debug print routines to direct
192 their output to the UART on Highbank based devices.
194 config DEBUG_IMX1_UART
195 bool "i.MX1 Debug UART"
196 depends on SOC_IMX1
197 help
198 Say Y here if you want kernel low-level debugging support
199 on i.MX1.
201 config DEBUG_IMX23_UART
202 bool "i.MX23 Debug UART"
203 depends on SOC_IMX23
204 help
205 Say Y here if you want kernel low-level debugging support
206 on i.MX23.
208 config DEBUG_IMX25_UART
209 bool "i.MX25 Debug UART"
210 depends on SOC_IMX25
211 help
212 Say Y here if you want kernel low-level debugging support
213 on i.MX25.
215 config DEBUG_IMX21_IMX27_UART
216 bool "i.MX21 and i.MX27 Debug UART"
217 depends on SOC_IMX21 || SOC_IMX27
218 help
219 Say Y here if you want kernel low-level debugging support
220 on i.MX21 or i.MX27.
222 config DEBUG_IMX28_UART
223 bool "i.MX28 Debug UART"
224 depends on SOC_IMX28
225 help
226 Say Y here if you want kernel low-level debugging support
227 on i.MX28.
229 config DEBUG_IMX31_IMX35_UART
230 bool "i.MX31 and i.MX35 Debug UART"
231 depends on SOC_IMX31 || SOC_IMX35
232 help
233 Say Y here if you want kernel low-level debugging support
234 on i.MX31 or i.MX35.
236 config DEBUG_IMX51_UART
237 bool "i.MX51 Debug UART"
238 depends on SOC_IMX51
239 help
240 Say Y here if you want kernel low-level debugging support
241 on i.MX51.
243 config DEBUG_IMX50_IMX53_UART
244 bool "i.MX50 and i.MX53 Debug UART"
245 depends on SOC_IMX50 || SOC_IMX53
246 help
247 Say Y here if you want kernel low-level debugging support
248 on i.MX50 or i.MX53.
250 config DEBUG_IMX6Q_UART
251 bool "i.MX6Q Debug UART"
252 depends on SOC_IMX6Q
253 help
254 Say Y here if you want kernel low-level debugging support
255 on i.MX6Q.
257 config DEBUG_MMP_UART2
258 bool "Kernel low-level debugging message via MMP UART2"
259 depends on ARCH_MMP
260 help
261 Say Y here if you want kernel low-level debugging support
262 on MMP UART2.
264 config DEBUG_MMP_UART3
265 bool "Kernel low-level debugging message via MMP UART3"
266 depends on ARCH_MMP
267 help
268 Say Y here if you want kernel low-level debugging support
269 on MMP UART3.
271 config DEBUG_MSM_UART1
272 bool "Kernel low-level debugging messages via MSM UART1"
273 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
274 help
275 Say Y here if you want the debug print routines to direct
276 their output to the first serial port on MSM devices.
278 config DEBUG_MSM_UART2
279 bool "Kernel low-level debugging messages via MSM UART2"
280 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
281 help
282 Say Y here if you want the debug print routines to direct
283 their output to the second serial port on MSM devices.
285 config DEBUG_MSM_UART3
286 bool "Kernel low-level debugging messages via MSM UART3"
287 depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
288 help
289 Say Y here if you want the debug print routines to direct
290 their output to the third serial port on MSM devices.
292 config DEBUG_MSM8660_UART
293 bool "Kernel low-level debugging messages via MSM 8660 UART"
294 depends on ARCH_MSM8X60
295 select MSM_HAS_DEBUG_UART_HS
296 help
297 Say Y here if you want the debug print routines to direct
298 their output to the serial port on MSM 8660 devices.
300 config DEBUG_MSM8960_UART
301 bool "Kernel low-level debugging messages via MSM 8960 UART"
302 depends on ARCH_MSM8960
303 select MSM_HAS_DEBUG_UART_HS
304 help
305 Say Y here if you want the debug print routines to direct
306 their output to the serial port on MSM 8960 devices.
308 config DEBUG_MVEBU_UART
309 bool "Kernel low-level debugging messages via MVEBU UART"
310 depends on ARCH_MVEBU
311 help
312 Say Y here if you want kernel low-level debugging support
313 on MVEBU based platforms.
315 config DEBUG_PICOXCELL_UART
316 depends on ARCH_PICOXCELL
317 bool "Use PicoXcell UART for low-level debug"
318 help
319 Say Y here if you want kernel low-level debugging support
320 on PicoXcell based platforms.
322 config DEBUG_REALVIEW_STD_PORT
323 bool "RealView Default UART"
324 depends on ARCH_REALVIEW
325 help
326 Say Y here if you want the debug print routines to direct
327 their output to the serial port on RealView EB, PB11MP, PBA8
328 and PBX platforms.
330 config DEBUG_REALVIEW_PB1176_PORT
331 bool "RealView PB1176 UART"
332 depends on MACH_REALVIEW_PB1176
333 help
334 Say Y here if you want the debug print routines to direct
335 their output to the standard serial port on the RealView
336 PB1176 platform.
338 config DEBUG_S3C_UART0
339 depends on PLAT_SAMSUNG
340 bool "Use S3C UART 0 for low-level debug"
341 help
342 Say Y here if you want the debug print routines to direct
343 their output to UART 0. The port must have been initialised
344 by the boot-loader before use.
346 The uncompressor code port configuration is now handled
347 by CONFIG_S3C_LOWLEVEL_UART_PORT.
349 config DEBUG_S3C_UART1
350 depends on PLAT_SAMSUNG
351 bool "Use S3C UART 1 for low-level debug"
352 help
353 Say Y here if you want the debug print routines to direct
354 their output to UART 1. The port must have been initialised
355 by the boot-loader before use.
357 The uncompressor code port configuration is now handled
358 by CONFIG_S3C_LOWLEVEL_UART_PORT.
360 config DEBUG_S3C_UART2
361 depends on PLAT_SAMSUNG
362 bool "Use S3C UART 2 for low-level debug"
363 help
364 Say Y here if you want the debug print routines to direct
365 their output to UART 2. The port must have been initialised
366 by the boot-loader before use.
368 The uncompressor code port configuration is now handled
369 by CONFIG_S3C_LOWLEVEL_UART_PORT.
371 config DEBUG_S3C_UART3
372 depends on PLAT_SAMSUNG && ARCH_EXYNOS
373 bool "Use S3C UART 3 for low-level debug"
374 help
375 Say Y here if you want the debug print routines to direct
376 their output to UART 3. The port must have been initialised
377 by the boot-loader before use.
379 The uncompressor code port configuration is now handled
380 by CONFIG_S3C_LOWLEVEL_UART_PORT.
382 config DEBUG_SOCFPGA_UART
383 depends on ARCH_SOCFPGA
384 bool "Use SOCFPGA UART for low-level debug"
385 help
386 Say Y here if you want kernel low-level debugging support
387 on SOCFPGA based platforms.
389 config DEBUG_SUNXI_UART0
390 bool "Kernel low-level debugging messages via sunXi UART0"
391 depends on ARCH_SUNXI
392 help
393 Say Y here if you want kernel low-level debugging support
394 on Allwinner A1X based platforms on the UART0.
396 config DEBUG_SUNXI_UART1
397 bool "Kernel low-level debugging messages via sunXi UART1"
398 depends on ARCH_SUNXI
399 help
400 Say Y here if you want kernel low-level debugging support
401 on Allwinner A1X based platforms on the UART1.
403 config DEBUG_TEGRA_UART
404 depends on ARCH_TEGRA
405 bool "Use Tegra UART for low-level debug"
406 help
407 Say Y here if you want kernel low-level debugging support
408 on Tegra based platforms.
410 config DEBUG_VEXPRESS_UART0_DETECT
411 bool "Autodetect UART0 on Versatile Express Cortex-A core tiles"
412 depends on ARCH_VEXPRESS && CPU_CP15_MMU
413 help
414 This option enables a simple heuristic which tries to determine
415 the motherboard's memory map variant (original or RS1) and then
416 choose the relevant UART0 base address.
418 Note that this will only work with standard A-class core tiles,
419 and may fail with non-standard SMM or custom software models.
421 config DEBUG_VEXPRESS_UART0_CA9
422 bool "Use PL011 UART0 at 0x10009000 (V2P-CA9 core tile)"
423 depends on ARCH_VEXPRESS
424 help
425 This option selects UART0 at 0x10009000. Except for custom models,
426 this applies only to the V2P-CA9 tile.
428 config DEBUG_VEXPRESS_UART0_RS1
429 bool "Use PL011 UART0 at 0x1c090000 (RS1 complaint tiles)"
430 depends on ARCH_VEXPRESS
431 help
432 This option selects UART0 at 0x1c090000. This applies to most
433 of the tiles using the RS1 memory map, including all new A-class
434 core tiles, FPGA-based SMMs and software models.
436 config DEBUG_LL_UART_NONE
437 bool "No low-level debugging UART"
438 depends on !ARCH_MULTIPLATFORM
439 help
440 Say Y here if your platform doesn't provide a UART option
441 below. This relies on your platform choosing the right UART
442 definition internally in order for low-level debugging to
443 work.
445 config DEBUG_ICEDCC
446 bool "Kernel low-level debugging via EmbeddedICE DCC channel"
447 help
448 Say Y here if you want the debug print routines to direct
449 their output to the EmbeddedICE macrocell's DCC channel using
450 co-processor 14. This is known to work on the ARM9 style ICE
451 channel and on the XScale with the PEEDI.
453 Note that the system will appear to hang during boot if there
454 is nothing connected to read from the DCC.
456 config DEBUG_SEMIHOSTING
457 bool "Kernel low-level debug output via semihosting I/O"
458 help
459 Semihosting enables code running on an ARM target to use
460 the I/O facilities on a host debugger/emulator through a
461 simple SVC call. The host debugger or emulator must have
462 semihosting enabled for the special svc call to be trapped
463 otherwise the kernel will crash.
465 This is known to work with OpenOCD, as well as
466 ARM's Fast Models, or any other controlling environment
467 that implements semihosting.
469 For more details about semihosting, please see
470 chapter 8 of DUI0203I_rvct_developer_guide.pdf from ARM Ltd.
472 endchoice
474 config DEBUG_IMX6Q_UART_PORT
475 int "i.MX6Q Debug UART Port (1-5)" if DEBUG_IMX6Q_UART
476 range 1 5
477 default 1
478 depends on SOC_IMX6Q
479 help
480 Choose UART port on which kernel low-level debug messages
481 should be output.
483 choice
484 prompt "Low-level debug console UART"
485 depends on DEBUG_LL && DEBUG_TEGRA_UART
487 config TEGRA_DEBUG_UART_AUTO_ODMDATA
488 bool "Via ODMDATA"
489 help
490 Automatically determines which UART to use for low-level debug based
491 on the ODMDATA value. This value is part of the BCT, and is written
492 to the boot memory device using nvflash, or other flashing tool.
493 When bits 19:18 are 3, then bits 17:15 indicate which UART to use;
494 0/1/2/3/4 are UART A/B/C/D/E.
496 config TEGRA_DEBUG_UARTA
497 bool "UART A"
499 config TEGRA_DEBUG_UARTB
500 bool "UART B"
502 config TEGRA_DEBUG_UARTC
503 bool "UART C"
505 config TEGRA_DEBUG_UARTD
506 bool "UART D"
508 config TEGRA_DEBUG_UARTE
509 bool "UART E"
511 endchoice
513 config DEBUG_LL_INCLUDE
514 string
515 default "debug/icedcc.S" if DEBUG_ICEDCC
516 default "debug/imx.S" if DEBUG_IMX1_UART || \
517 DEBUG_IMX25_UART || \
518 DEBUG_IMX21_IMX27_UART || \
519 DEBUG_IMX31_IMX35_UART || \
520 DEBUG_IMX51_UART || \
521 DEBUG_IMX50_IMX53_UART ||\
522 DEBUG_IMX6Q_UART
523 default "debug/highbank.S" if DEBUG_HIGHBANK_UART
524 default "debug/mvebu.S" if DEBUG_MVEBU_UART
525 default "debug/picoxcell.S" if DEBUG_PICOXCELL_UART
526 default "debug/socfpga.S" if DEBUG_SOCFPGA_UART
527 default "debug/sunxi.S" if DEBUG_SUNXI_UART0 || DEBUG_SUNXI_UART1
528 default "debug/vexpress.S" if DEBUG_VEXPRESS_UART0_DETECT || \
529 DEBUG_VEXPRESS_UART0_CA9 || DEBUG_VEXPRESS_UART0_RS1
530 default "debug/tegra.S" if DEBUG_TEGRA_UART
531 default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1
532 default "mach/debug-macro.S"
534 config EARLY_PRINTK
535 bool "Early printk"
536 depends on DEBUG_LL
537 help
538 Say Y here if you want to have an early console using the
539 kernel low-level debugging functions. Add earlyprintk to your
540 kernel parameters to enable this console.
542 config OC_ETM
543 bool "On-chip ETM and ETB"
544 depends on ARM_AMBA
545 help
546 Enables the on-chip embedded trace macrocell and embedded trace
547 buffer driver that will allow you to collect traces of the
548 kernel code.
550 config ARM_KPROBES_TEST
551 tristate "Kprobes test module"
552 depends on KPROBES && MODULES
553 help
554 Perform tests of kprobes API and instruction set simulation.
556 config PID_IN_CONTEXTIDR
557 bool "Write the current PID to the CONTEXTIDR register"
558 depends on CPU_COPY_V6
559 help
560 Enabling this option causes the kernel to write the current PID to
561 the PROCID field of the CONTEXTIDR register, at the expense of some
562 additional instructions during context switch. Say Y here only if you
563 are planning to use hardware trace tools with this kernel.
565 endmenu