[linux-block.git] / arch / arm / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

config STRICT_DEVMEM
	bool "Filter access to /dev/mem"
	depends on MMU
	---help---
	  If this option is disabled, you allow userspace (root) access to all
	  of memory, including kernel and userspace memory. Accidental
	  access to this is obviously disastrous, but specific access can
	  be used by people debugging the kernel.

	  If this option is switched on, the /dev/mem file only allows
	  userspace access to memory mapped peripherals.

          If in doubt, say Y.

# RMK wants arm kernels compiled with frame pointers or stack unwinding.
# If you know what you are doing and are willing to live without stack
# traces, you can get a slightly smaller kernel by setting this option to
# n, but then RMK will have to kill you ;).
config FRAME_POINTER
	bool
	depends on !THUMB2_KERNEL
	default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
	help
	  If you say N here, the resulting kernel will be slightly smaller and
	  faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled,
	  when a problem occurs with the kernel, the information that is
	  reported is severely limited.

config ARM_UNWIND
	bool "Enable stack unwinding support (EXPERIMENTAL)"
	depends on AEABI
	default y
	help
	  This option enables stack unwinding support in the kernel
	  using the information automatically generated by the
	  compiler. The resulting kernel image is slightly bigger but
	  the performance is not affected. Currently, this feature
	  only works with EABI compilers. If unsure say Y.

config OLD_MCOUNT
	bool
	depends on FUNCTION_TRACER && FRAME_POINTER
	default y

config DEBUG_USER
	bool "Verbose user fault messages"
	help
	  When a user program crashes due to an exception, the kernel can
	  print a brief message explaining what the problem was. This is
	  sometimes helpful for debugging but serves no purpose on a
	  production system. Most people should say N here.

	  In addition, you need to pass user_debug=N on the kernel command
	  line to enable this feature.  N consists of the sum of:

	      1 - undefined instruction events
	      2 - system calls
	      4 - invalid data aborts
	      8 - SIGSEGV faults
	     16 - SIGBUS faults

# These options are only for real kernel hackers who want to get their hands dirty.
config DEBUG_LL
	bool "Kernel low-level debugging functions (read help!)"
	depends on DEBUG_KERNEL
	help
	  Say Y here to include definitions of printascii, printch, printhex
	  in the kernel.  This is helpful if you are debugging code that
	  executes before the console is initialized.

	  Note that selecting this option will limit the kernel to a single
	  UART definition, as specified below. Attempting to boot the kernel
	  image on a different platform *will not work*, so this option should
	  not be enabled for kernels that are intended to be portable.

choice
	prompt "Kernel low-level debugging port"
	depends on DEBUG_LL

	config AT91_DEBUG_LL_DBGU0
		bool "Kernel low-level debugging on rm9200, 9260/9g20, 9261/9g10 and 9rl"
		depends on HAVE_AT91_DBGU0

	config AT91_DEBUG_LL_DBGU1
		bool "Kernel low-level debugging on 9263 and 9g45"
		depends on HAVE_AT91_DBGU1

	config DEBUG_BCM2835
		bool "Kernel low-level debugging on BCM2835 PL011 UART"
		depends on ARCH_BCM2835

	config DEBUG_CLPS711X_UART1
		bool "Kernel low-level debugging messages via UART1"
		depends on ARCH_CLPS711X
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the first serial port on these devices.

	config DEBUG_CLPS711X_UART2
		bool "Kernel low-level debugging messages via UART2"
		depends on ARCH_CLPS711X
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the second serial port on these devices.

	config DEBUG_CNS3XXX
		bool "Kernel Kernel low-level debugging on Cavium Networks CNS3xxx"
		depends on ARCH_CNS3XXX
		help
		  Say Y here if you want the debug print routines to direct
                  their output to the CNS3xxx UART0.

	config DEBUG_DAVINCI_DA8XX_UART1
		bool "Kernel low-level debugging on DaVinci DA8XX using UART1"
		depends on ARCH_DAVINCI_DA8XX
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART1 serial port on DaVinci DA8XX devices.

	config DEBUG_DAVINCI_DA8XX_UART2
		bool "Kernel low-level debugging on DaVinci DA8XX using UART2"
		depends on ARCH_DAVINCI_DA8XX
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART2 serial port on DaVinci DA8XX devices.

	config DEBUG_DAVINCI_DMx_UART0
		bool "Kernel low-level debugging on DaVinci DMx using UART0"
		depends on ARCH_DAVINCI_DMx
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART0 serial port on DaVinci DMx devices.

	config DEBUG_DAVINCI_TNETV107X_UART1
		bool "Kernel low-level debugging on DaVinci TNETV107x using UART1"
		depends on ARCH_DAVINCI_TNETV107X
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART1 serial port on DaVinci TNETV107X
		  devices.

	config DEBUG_ZYNQ_UART0
		bool "Kernel low-level debugging on Xilinx Zynq using UART0"
		depends on ARCH_ZYNQ
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART0 on the Zynq platform.

	config DEBUG_ZYNQ_UART1
		bool "Kernel low-level debugging on Xilinx Zynq using UART1"
		depends on ARCH_ZYNQ
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART1 on the Zynq platform.

		  If you have a ZC702 board and want early boot messages to
		  appear on the USB serial adaptor, select this option.

	config DEBUG_DC21285_PORT
		bool "Kernel low-level debugging messages via footbridge serial port"
		depends on FOOTBRIDGE
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the serial port in the DC21285 (Footbridge).

	config DEBUG_FOOTBRIDGE_COM1
		bool "Kernel low-level debugging messages via footbridge 8250 at PCI COM1"
		depends on FOOTBRIDGE
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the 8250 at PCI COM1.

	config DEBUG_HIGHBANK_UART
		bool "Kernel low-level debugging messages via Highbank UART"
		depends on ARCH_HIGHBANK
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the UART on Highbank based devices.

	config DEBUG_IMX1_UART
		bool "i.MX1 Debug UART"
		depends on SOC_IMX1
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX1.

	config DEBUG_IMX23_UART
		bool "i.MX23 Debug UART"
		depends on SOC_IMX23
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX23.

	config DEBUG_IMX25_UART
		bool "i.MX25 Debug UART"
		depends on SOC_IMX25
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX25.

	config DEBUG_IMX21_IMX27_UART
		bool "i.MX21 and i.MX27 Debug UART"
		depends on SOC_IMX21 || SOC_IMX27
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX21 or i.MX27.

	config DEBUG_IMX28_UART
		bool "i.MX28 Debug UART"
		depends on SOC_IMX28
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX28.

	config DEBUG_IMX31_UART
		bool "i.MX31 Debug UART"
		depends on SOC_IMX31
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX31.

	config DEBUG_IMX35_UART
		bool "i.MX35 Debug UART"
		depends on SOC_IMX35
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX35.

	config DEBUG_IMX51_UART
		bool "i.MX51 Debug UART"
		depends on SOC_IMX51
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX51.

	config DEBUG_IMX53_UART
		bool "i.MX53 Debug UART"
		depends on SOC_IMX53
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX53.

	config DEBUG_IMX6Q_UART
		bool "i.MX6Q Debug UART"
		depends on SOC_IMX6Q
		help
		  Say Y here if you want kernel low-level debugging support
		  on i.MX6Q.

	config DEBUG_MMP_UART2
		bool "Kernel low-level debugging message via MMP UART2"
		depends on ARCH_MMP
		help
		  Say Y here if you want kernel low-level debugging support
		  on MMP UART2.

	config DEBUG_MMP_UART3
		bool "Kernel low-level debugging message via MMP UART3"
		depends on ARCH_MMP
		help
		  Say Y here if you want kernel low-level debugging support
		  on MMP UART3.

	config DEBUG_MSM_UART1
		bool "Kernel low-level debugging messages via MSM UART1"
		depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the first serial port on MSM devices.

	config DEBUG_MSM_UART2
		bool "Kernel low-level debugging messages via MSM UART2"
		depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the second serial port on MSM devices.

	config DEBUG_MSM_UART3
		bool "Kernel low-level debugging messages via MSM UART3"
		depends on ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the third serial port on MSM devices.

	config DEBUG_MSM8660_UART
		bool "Kernel low-level debugging messages via MSM 8660 UART"
		depends on ARCH_MSM8X60
		select MSM_HAS_DEBUG_UART_HS
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the serial port on MSM 8660 devices.

	config DEBUG_MSM8960_UART
		bool "Kernel low-level debugging messages via MSM 8960 UART"
		depends on ARCH_MSM8960
		select MSM_HAS_DEBUG_UART_HS
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the serial port on MSM 8960 devices.

	config DEBUG_MVEBU_UART
		bool "Kernel low-level debugging messages via MVEBU UART"
		depends on ARCH_MVEBU
		help
		  Say Y here if you want kernel low-level debugging support
		  on MVEBU based platforms.

	config DEBUG_NOMADIK_UART
		bool "Kernel low-level debugging messages via NOMADIK UART"
		depends on ARCH_NOMADIK
		help
		  Say Y here if you want kernel low-level debugging support
		  on NOMADIK based platforms.

	config DEBUG_OMAP2PLUS_UART
		bool "Kernel low-level debugging messages via OMAP2PLUS UART"
		depends on ARCH_OMAP2PLUS
		help
		  Say Y here if you want kernel low-level debugging support
		  on OMAP2PLUS based platforms.

	config DEBUG_PICOXCELL_UART
		depends on ARCH_PICOXCELL
		bool "Use PicoXcell UART for low-level debug"
		help
		  Say Y here if you want kernel low-level debugging support
		  on PicoXcell based platforms.

	config DEBUG_REALVIEW_STD_PORT
		bool "RealView Default UART"
		depends on ARCH_REALVIEW
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the serial port on RealView EB, PB11MP, PBA8
		  and PBX platforms.

	config DEBUG_REALVIEW_PB1176_PORT
		bool "RealView PB1176 UART"
		depends on MACH_REALVIEW_PB1176
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the standard serial port on the RealView
		  PB1176 platform.

	config DEBUG_S3C_UART0
		depends on PLAT_SAMSUNG
		select DEBUG_EXYNOS_UART if ARCH_EXYNOS
		bool "Use S3C UART 0 for low-level debug"
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART 0. The port must have been initialised
		  by the boot-loader before use.

		  The uncompressor code port configuration is now handled
		  by CONFIG_S3C_LOWLEVEL_UART_PORT.

	config DEBUG_S3C_UART1
		depends on PLAT_SAMSUNG
		select DEBUG_EXYNOS_UART if ARCH_EXYNOS
		bool "Use S3C UART 1 for low-level debug"
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART 1. The port must have been initialised
		  by the boot-loader before use.

		  The uncompressor code port configuration is now handled
		  by CONFIG_S3C_LOWLEVEL_UART_PORT.

	config DEBUG_S3C_UART2
		depends on PLAT_SAMSUNG
		select DEBUG_EXYNOS_UART if ARCH_EXYNOS
		bool "Use S3C UART 2 for low-level debug"
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART 2. The port must have been initialised
		  by the boot-loader before use.

		  The uncompressor code port configuration is now handled
		  by CONFIG_S3C_LOWLEVEL_UART_PORT.

	config DEBUG_S3C_UART3
		depends on PLAT_SAMSUNG && ARCH_EXYNOS
		select DEBUG_EXYNOS_UART
		bool "Use S3C UART 3 for low-level debug"
		help
		  Say Y here if you want the debug print routines to direct
		  their output to UART 3. The port must have been initialised
		  by the boot-loader before use.

		  The uncompressor code port configuration is now handled
		  by CONFIG_S3C_LOWLEVEL_UART_PORT.

	config DEBUG_SOCFPGA_UART
		depends on ARCH_SOCFPGA
		bool "Use SOCFPGA UART for low-level debug"
		help
		  Say Y here if you want kernel low-level debugging support
		  on SOCFPGA based platforms.

	config DEBUG_SUNXI_UART0
		bool "Kernel low-level debugging messages via sunXi UART0"
		depends on ARCH_SUNXI
		help
		  Say Y here if you want kernel low-level debugging support
		  on Allwinner A1X based platforms on the UART0.

	config DEBUG_SUNXI_UART1
		bool "Kernel low-level debugging messages via sunXi UART1"
		depends on ARCH_SUNXI
		help
		  Say Y here if you want kernel low-level debugging support
		  on Allwinner A1X based platforms on the UART1.

	config DEBUG_TEGRA_UART
		depends on ARCH_TEGRA
		bool "Use Tegra UART for low-level debug"
		help
		  Say Y here if you want kernel low-level debugging support
		  on Tegra based platforms.

	config DEBUG_SIRFPRIMA2_UART1
		bool "Kernel low-level debugging messages via SiRFprimaII UART1"
		depends on ARCH_PRIMA2
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the uart1 port on SiRFprimaII devices.

	config DEBUG_SIRFMARCO_UART1
		bool "Kernel low-level debugging messages via SiRFmarco UART1"
		depends on ARCH_MARCO
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the uart1 port on SiRFmarco devices.

	config DEBUG_UX500_UART
		depends on ARCH_U8500
		bool "Use Ux500 UART for low-level debug"
		help
		  Say Y here if you want kernel low-level debugging support
		  on Ux500 based platforms.

	config DEBUG_VEXPRESS_UART0_DETECT
		bool "Autodetect UART0 on Versatile Express Cortex-A core tiles"
		depends on ARCH_VEXPRESS && CPU_CP15_MMU
		help
		  This option enables a simple heuristic which tries to determine
		  the motherboard's memory map variant (original or RS1) and then
		  choose the relevant UART0 base address.

		  Note that this will only work with standard A-class core tiles,
		  and may fail with non-standard SMM or custom software models.

	config DEBUG_VEXPRESS_UART0_CA9
		bool "Use PL011 UART0 at 0x10009000 (V2P-CA9 core tile)"
		depends on ARCH_VEXPRESS
		help
		  This option selects UART0 at 0x10009000. Except for custom models,
		  this applies only to the V2P-CA9 tile.

	config DEBUG_VEXPRESS_UART0_RS1
		bool "Use PL011 UART0 at 0x1c090000 (RS1 complaint tiles)"
		depends on ARCH_VEXPRESS
		help
		  This option selects UART0 at 0x1c090000. This applies to most
		  of the tiles using the RS1 memory map, including all new A-class
		  core tiles, FPGA-based SMMs and software models.

	config DEBUG_VT8500_UART0
		bool "Use UART0 on VIA/Wondermedia SoCs"
		depends on ARCH_VT8500
		help
		  This option selects UART0 on VIA/Wondermedia System-on-a-chip
		  devices, including VT8500, WM8505, WM8650 and WM8850.

	config DEBUG_LL_UART_NONE
		bool "No low-level debugging UART"
		depends on !ARCH_MULTIPLATFORM
		help
		  Say Y here if your platform doesn't provide a UART option
		  below. This relies on your platform choosing the right UART
		  definition internally in order for low-level debugging to
		  work.

	config DEBUG_ICEDCC
		bool "Kernel low-level debugging via EmbeddedICE DCC channel"
		help
		  Say Y here if you want the debug print routines to direct
		  their output to the EmbeddedICE macrocell's DCC channel using
		  co-processor 14. This is known to work on the ARM9 style ICE
		  channel and on the XScale with the PEEDI.

		  Note that the system will appear to hang during boot if there
		  is nothing connected to read from the DCC.

	config DEBUG_SEMIHOSTING
		bool "Kernel low-level debug output via semihosting I/O"
		help
		  Semihosting enables code running on an ARM target to use
		  the I/O facilities on a host debugger/emulator through a
		  simple SVC call. The host debugger or emulator must have
		  semihosting enabled for the special svc call to be trapped
		  otherwise the kernel will crash.

		  This is known to work with OpenOCD, as well as
		  ARM's Fast Models, or any other controlling environment
		  that implements semihosting.

		  For more details about semihosting, please see
		  chapter 8 of DUI0203I_rvct_developer_guide.pdf from ARM Ltd.

endchoice

config DEBUG_EXYNOS_UART
	bool

config DEBUG_IMX_UART_PORT
	int "i.MX Debug UART Port Selection" if DEBUG_IMX1_UART || \
						DEBUG_IMX25_UART || \
						DEBUG_IMX21_IMX27_UART || \
						DEBUG_IMX31_UART || \
						DEBUG_IMX35_UART || \
						DEBUG_IMX51_UART || \
						DEBUG_IMX53_UART || \
						DEBUG_IMX6Q_UART
	default 1
	depends on ARCH_MXC
	help
	  Choose UART port on which kernel low-level debug messages
	  should be output.

choice
	prompt "Low-level debug console UART"
	depends on DEBUG_OMAP2PLUS_UART

	config DEBUG_OMAP2UART1
		bool "OMAP2/3/4 UART1 (omap2/3 sdp boards and some omap3 boards)"
		help
		  This covers at least h4, 2430sdp, 3430sdp, 3630sdp,
		  omap3 torpedo and 3530 lv som.

	config DEBUG_OMAP2UART2
		bool "OMAP2/3/4 UART2"

	config DEBUG_OMAP2UART3
		bool "OMAP2 UART3 (n8x0)"

	config DEBUG_OMAP3UART3
		bool "OMAP3 UART3 (most omap3 boards)"
		help
		  This covers at least cm_t3x, beagle, crane, devkit8000,
		  igep00x0, ldp, n900, n9(50), pandora, overo, touchbook,
		  and 3517evm.

	config DEBUG_OMAP4UART3
		bool "OMAP4/5 UART3 (omap4 blaze, panda, omap5 sevm)"

	config DEBUG_OMAP3UART4
		bool "OMAP36XX UART4"

	config DEBUG_OMAP4UART4
		bool "OMAP4/5 UART4"

	config DEBUG_TI81XXUART1
		bool "TI81XX UART1 (ti8148evm)"

	config DEBUG_TI81XXUART2
		bool "TI81XX UART2"

	config DEBUG_TI81XXUART3
		bool "TI81XX UART3 (ti8168evm)"

	config DEBUG_AM33XXUART1
		bool "AM33XX UART1"

	config DEBUG_ZOOM_UART
		bool "Zoom2/3 UART"
endchoice

choice
	prompt "Low-level debug console UART"
	depends on DEBUG_LL && DEBUG_TEGRA_UART

	config TEGRA_DEBUG_UART_AUTO_ODMDATA
	bool "Via ODMDATA"
	help
	  Automatically determines which UART to use for low-level debug based
	  on the ODMDATA value. This value is part of the BCT, and is written
	  to the boot memory device using nvflash, or other flashing tool.
	  When bits 19:18 are 3, then bits 17:15 indicate which UART to use;
	  0/1/2/3/4 are UART A/B/C/D/E.

	config TEGRA_DEBUG_UARTA
		bool "UART A"

	config TEGRA_DEBUG_UARTB
		bool "UART B"

	config TEGRA_DEBUG_UARTC
		bool "UART C"

	config TEGRA_DEBUG_UARTD
		bool "UART D"

	config TEGRA_DEBUG_UARTE
		bool "UART E"

endchoice

config DEBUG_LL_INCLUDE
	string
	default "debug/bcm2835.S" if DEBUG_BCM2835
	default "debug/cns3xxx.S" if DEBUG_CNS3XXX
	default "debug/exynos.S" if DEBUG_EXYNOS_UART
	default "debug/icedcc.S" if DEBUG_ICEDCC
	default "debug/imx.S" if DEBUG_IMX1_UART || \
				 DEBUG_IMX25_UART || \
				 DEBUG_IMX21_IMX27_UART || \
				 DEBUG_IMX31_UART || \
				 DEBUG_IMX35_UART || \
				 DEBUG_IMX51_UART || \
				 DEBUG_IMX53_UART ||\
				 DEBUG_IMX6Q_UART
	default "debug/highbank.S" if DEBUG_HIGHBANK_UART
	default "debug/mvebu.S" if DEBUG_MVEBU_UART
	default "debug/mxs.S" if DEBUG_IMX23_UART || DEBUG_IMX28_UART
	default "debug/nomadik.S" if DEBUG_NOMADIK_UART
	default "debug/omap2plus.S" if DEBUG_OMAP2PLUS_UART
	default "debug/picoxcell.S" if DEBUG_PICOXCELL_UART
	default "debug/sirf.S" if DEBUG_SIRFPRIMA2_UART1 || DEBUG_SIRFMARCO_UART1
	default "debug/socfpga.S" if DEBUG_SOCFPGA_UART
	default "debug/sunxi.S" if DEBUG_SUNXI_UART0 || DEBUG_SUNXI_UART1
	default "debug/vexpress.S" if DEBUG_VEXPRESS_UART0_DETECT || \
		DEBUG_VEXPRESS_UART0_CA9 || DEBUG_VEXPRESS_UART0_RS1
	default "debug/vt8500.S" if DEBUG_VT8500_UART0
	default "debug/tegra.S" if DEBUG_TEGRA_UART
	default "debug/ux500.S" if DEBUG_UX500_UART
	default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1
	default "mach/debug-macro.S"

config DEBUG_UNCOMPRESS
	bool
	default y if ARCH_MULTIPLATFORM && DEBUG_LL && \
		     !DEBUG_OMAP2PLUS_UART && \
		     !DEBUG_TEGRA_UART

config UNCOMPRESS_INCLUDE
	string
	default "debug/uncompress.h" if ARCH_MULTIPLATFORM
	default "mach/uncompress.h"

config EARLY_PRINTK
	bool "Early printk"
	depends on DEBUG_LL
	help
	  Say Y here if you want to have an early console using the
	  kernel low-level debugging functions. Add earlyprintk to your
	  kernel parameters to enable this console.

config OC_ETM
	bool "On-chip ETM and ETB"
	depends on ARM_AMBA
	help
	  Enables the on-chip embedded trace macrocell and embedded trace
	  buffer driver that will allow you to collect traces of the
	  kernel code.

config ARM_KPROBES_TEST
	tristate "Kprobes test module"
	depends on KPROBES && MODULES
	help
	  Perform tests of kprobes API and instruction set simulation.

config PID_IN_CONTEXTIDR
	bool "Write the current PID to the CONTEXTIDR register"
	depends on CPU_COPY_V6
	help
	  Enabling this option causes the kernel to write the current PID to
	  the PROCID field of the CONTEXTIDR register, at the expense of some
	  additional instructions during context switch. Say Y here only if you
	  are planning to use hardware trace tools with this kernel.

endmenu