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317 lines
9.0 KiB
Plaintext
317 lines
9.0 KiB
Plaintext
# Target definition: architecture, optimisations, etc...
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menu "Target options"
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comment "General target options"
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choice
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bool
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prompt "Target architecture:"
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default ARCH_x86
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config ARCH_ARM
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bool
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prompt "arm"
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select ARCH_SUPPORTS_BE
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select ARCH_SUPPORTS_LE
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config ARCH_MIPS
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bool
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prompt "mips"
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select ARCH_SUPPORTS_BE
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select ARCH_SUPPORTS_LE
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config ARCH_x86
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bool
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prompt "x86"
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select ARCH_SUPPORTS_LE
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config ARCH_x86_64
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bool
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prompt "x86_64"
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select ARCH_SUPPORTS_LE
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endchoice
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config ARCH_SUPPORTS_BE
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bool
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default n
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config ARCH_SUPPORTS_LE
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bool
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default n
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choice
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bool
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prompt "Endianness:"
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config ARCH_BE
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bool
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prompt "Big endian"
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depends on ARCH_SUPPORTS_BE
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config ARCH_LE
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bool
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prompt "Little endian"
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depends on ARCH_SUPPORTS_LE
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endchoice
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comment "Target optimisations"
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config ARCH_CPU
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string
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prompt "Emit assembly for CPU"
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default ""
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help
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This specifies the name of the target ARM processor. GCC uses this name
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to determine what kind of instructions it can emit when generating
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assembly code.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_TUNE
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string
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prompt "Tune for CPU"
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default ""
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help
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This option is very similar to the ARCH_CPU option (above), except
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that instead of specifying the actual target processor type, and hence
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restricting which instructions can be used, it specifies that GCC should
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tune the performance of the code as if the target were of the type
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specified in this option, but still choosing the instructions that it
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will generate based on the cpu specified by the ARCH_CPU option
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(above), or a (command-line) -mcpu= option.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_ARCH
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string
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prompt "Achitecture level"
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default ""
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help
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GCC uses this name to determine what kind of instructions it can emit
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when generating assembly code. This option can be used in conjunction
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with or instead of the ARCH_CPU option (above), or a (command-line)
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-mcpu= option.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_FPU
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string
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prompt "Use FPU"
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default ""
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help
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On some targets (eg. ARM), you can specify the kind of FPU to emit
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code for.
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See below wether to actually emit FP opcodes, or to emulate them.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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choice
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bool
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prompt "Floating point:"
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config ARCH_FLOAT_HW
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bool
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prompt "hardware (FPU)"
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help
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Emit hardware floating point opcodes.
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If you've got a processor with a FPU, then you want that.
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If your hardware has no FPU, you still can use HW floating point, but
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need to compile support for FPU emulation in your kernel. Needless to
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say that emulating the FPU is /slooowwwww/...
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One situation you'd want HW floating point without a FPU is if you get
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binary blobs from different vendors that are compiling this way and
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can't (don't wan't to) change.
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config ARCH_FLOAT_SW
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bool
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prompt "software"
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help
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Do not emit any hardware floating point opcode.
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If your processor has no FPU, then you most probably want this, as it
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is faster than emulating the FPU in the kernel.
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endchoice
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config ARCH_FLOAT_SW_LIBFLOAT
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bool
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prompt "Use libfloat"
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default n
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depends on ARCH_FLOAT_SW
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help
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For those targets upporting it, you can use libfloat for the software
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floating point emulation.
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Note that some versions of gcc have support code that supersedes libfloat,
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while others don't. Known version of gcc that don't have support code are
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versions prior to 3.0, and version above 4.0.
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You should check gcc before deciding to use libfloat.
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config TARGET_CFLAGS
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string
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prompt "Default target CFLAGS"
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default ""
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help
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Used to add specific options when compiling libraries of the toolchain,
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that will run on the target (eg. libc.so).
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Note that the options above for CPU, tune, arch and FPU will be
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automaticaly used. You don't need to specify them here.
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Leave blank if you don't know better.
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comment "Toolchain options"
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config USE_SYSROOT
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bool
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prompt "Use sysroot'ed toolchain"
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default y
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help
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Use the 'shinny new' sysroot feature of gcc: libraries split between
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prefix/target/sys-root/lib and prefix/target/sys-root/usr/lib
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You definitely want to say 'Y' here. Yes you do. I know you do. Say 'Y'.
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config SHARED_LIBS
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bool
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prompt "Build shared libraries"
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default y
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help
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Say 'y' here, unless you don't want shared libraries.
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You might not want shared librries if you're building for a target that
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don't support it (maybe some nommu targets, for example, or bare metal).
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config TARGET_MULTILIB
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bool
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# prompt "Enable 'multilib' support (EXPERIMENTAL)"
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default n
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help
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Enable the so-called 'multilib' support.
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With the same toolchain, and on some architectures, you will be able to
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build big and little endian binaries, soft- and hard-float, etc...
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See the gcc configure manual at http://gcc.gnu.org/install/configure.html
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to see what multilib your target supports.
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It's preferable for now to build two (or more) toolchains, one for each
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configuration you need to support (eg. one for thumb and one for ARM,
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etc...). You can use the vendor string to diferentiate those toolchains.
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config TARGET_VENDOR
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string
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prompt "Vendor string"
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default "unknown"
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help
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Vendor part of the machine triplet.
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A triplet is of the form arch-vendor-kernel-system.
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You can set the second part, vendor, to whatever you see fit.
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Use a single word, or use underscores "_" to separate words.
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Keep the default (unkown) if you don't know better.
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config TARGET_ALIAS
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string
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prompt "Target alias"
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default ""
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help
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Normaly, you'd call your toolchain component (especially gcc) by
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prefixing the target triplet followed by a dash and the component name
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(eg. armeb-unknown-linux-uclibc-gcc).
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You can enter a shortcut here. This string will be used to create
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symbolic links to the toolchain tools (eg. if you enter "foo-bar" here,
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then gcc for your toolchain will also be available as "foo-bar-gcc" along
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with the original name).
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You shouldn't need to enter anything here, unless you plan to manually
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call the tools (autotools-based ./configure will use the standard name).
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config ARCH
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string
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default "arm" if ARCH_ARM
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default "mips" if ARCH_MIPS
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default "x86" if ARCH_x86
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default "x86_64" if ARCH_x86_64
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config BUILD
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string
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prompt "Build system triplet"
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default ""
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help
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Canonical name of the machine building the toolchain.
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You should leave empty, unless you really now what you're doing.
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config CC_NATIVE
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string
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prompt "Native gcc"
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default "gcc"
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help
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The native C compiler.
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You can set this to an alternative compiler if you have more than one
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installed (eg. gcc is gcc-4.1.1 and you want to use gcc-3.4.6).
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You can leave this empty as well, in which case gcc will be used.
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config CANADIAN
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bool
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prompt "Canadian build (EXPERIMENTAL)"
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default n
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help
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A canadian build allows to build a compiler on a first machine
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(build system), that will run on second machine (host system),
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targetting a third machine (target system).
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An example where you'd want a candian cross-compiler is to create
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a native compiler for your target. In this case host and target
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are the same.
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config HOST
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string
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prompt "Host system triplet"
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default ""
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depends on CANADIAN
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help
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Canonical name of the machine serving as host.
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config HOST_CC
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string
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prompt "Host system compiler"
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default "${CT_HOST}-"
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depends on CANADIAN
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help
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C compiler targeting the host system.
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If HOST_CC ends with a dash (-), then it is considered to be the
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prefix to gcc (eg. x86-pc-linuc-gnu-).
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If it is empty, it is formed by appending '-gcc' to HOST.
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Else it is considered to be the complete name of the compiler, with
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full path, or without path (provided that it can be found in PATH).
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endmenu
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