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Diffstat (limited to 'documentation')
| -rw-r--r-- | documentation/poky-ref-manual/technical-details.xml | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/documentation/poky-ref-manual/technical-details.xml b/documentation/poky-ref-manual/technical-details.xml index f327806eb2..7905697ec0 100644 --- a/documentation/poky-ref-manual/technical-details.xml +++ b/documentation/poky-ref-manual/technical-details.xml @@ -566,6 +566,119 @@ </section> </section> +<section id='x32'> + <title>x32</title> + + <para> + x32 is a new processor-specific Application Binary Interface (psABI) for x86_64. + An ABI defines the calling conventions between functions in a processing environment. + The interface determines what registers are used and what the sizes are for various C data types. + </para> + + <para> + Some processing environments prefer using 32-bit applications even when running + on Intel 64-bit platforms. + Consider the i386 psABI, which is a very old 32-bit ABI for Intel 64-bit platforms. + The i386 psABI does not provide efficient use and access of the Intel 64-bit processor resources, + leaving the system underutilized. + Now consider the x86_64 psABI. + This ABI is newer and uses 64-bits for data sizes and program pointers. + The extra bits increase the footprint size of the programs, libraries, memory, and file system size + requirements. + Executing under the x32 psABI enables user programs to utilize CPU and system resources + more efficiently while keeping the memory footprint of the applications low. + Extra bits are used for registers but not for addressing mechanisms. + </para> + + <section id='support'> + <title>Support</title> + + <para> + While the x32 psABI is not fully implemented with this release of the Yocto Project, + it is partially functional. + As of this release of the Yocto Project, x32 psABI support exists as follows: + <itemizedlist> + <listitem><para>You can create packages and images using an x32 psABI on x86_64 architecture targets. + </para></listitem> + <listitem><para>You can use the x32 psABI support through the <filename>meta-x32</filename> + layer on top of the OE-core/Yocto layer.</para></listitem> + <listitem><para>You can use the toolchain for building x32 psABI program binaries and kernel support + from the <filename>experimental/meta-x32</filename> layer.</para></listitem> + <listitem><para>You can successfully build many recipes with the x32 toolchain.</para></listitem> + <listitem><para>You can create and boot <filename>core-image-minimal</filename> and + <filename>core-image-sato</filename> images.</para></listitem> + </itemizedlist> + </para> + </section> + + <section id='future-development-and-limitations'> + <title>Future Development and Limitations</title> + + <para> + For this release of the Yocto Project, the x32 psABI kernel and library interfaces + and their use are not finalized. + </para> + + <para> + Plans for the x32 psABI in the Yocto Project include the following: + <itemizedlist> + <listitem><para>Enhance and fix recipes so they fully + support x32 toolchains and binaries.</para></listitem> + <listitem><para>Complete RPM Package Manager (RPM) support for x32 binaries.</para></listitem> + <listitem><para>Support larger images.</para></listitem> + <listitem><para>Integrate x32 toolchain and kernel changes from + <filename>experimental/meta-x32</filename> into OE-core.</para></listitem> + </itemizedlist> + </para> + </section> + + <section id='using-x32-right-now'> + <title>Using x32 Right Now</title> + + <para> + Despite the fact that the x32 psABI is incomplete for this release of the Yocto Project, you can + use it to some degree. + Follow these steps to use the x32 spABI: + <itemizedlist> + <listitem><para>Add the <filename>experimental/meta-x32</filename> layer to your local + <ulink url='&YOCTO_DOCS_DEV_URL;#yocto-project-files'>Yocto Project Files</ulink> + Git repository. + You can find the <filename>experimental/meta-x32</filename> source repository at + <ulink url='&YOCTO_GIT_URL;'></ulink>.</para></listitem> + <listitem><para>Edit your <filename>conf/bblayers.conf</filename> file so that it includes + the <filename>experimental/meta-x32</filename>. + Here is an example: + <literallayout class='monospaced'> + BBLAYERS ?= " \ + /home/nitin/prj/poky.git/meta \ + /home/nitin/prj/poky.git/meta-yocto \ + /home/nitin/prj/meta-x32.git \ + " + </literallayout></para></listitem> + <listitem><para>Enable the x32 psABI tuning file for <filename>x86_64</filename> + machines by editing the <filename>conf/local.conf</filename> as follows: + <literallayout class='monospaced'> + MACHINE = "qemux86-64" + DEFAULTTUNE = "x86-64-x32" + baselib = "${@d.getVar('BASE_LIB_tune-' + (d.getVar('DEFAULTTUNE', True) \ + or 'INVALID'), True) or 'lib'}" + #MACHINE = "atom-pc" + #DEFAULTTUNE = "core2-64-x32" + </literallayout></para></listitem> + <listitem><para>Use BitBake to build an image that supports the x32 psABI. + Here is an example: + <literallayout class='monospaced'> + $ bitake core-image-sato + </literallayout></para></listitem> + <listitem><para>Run your image using QUEM: + <literallayout class='monospaced'> + $ runqemu qemux86-64 core-image-sato + </literallayout></para></listitem> + </itemizedlist> + </para> + </section> +</section> + <section id="licenses"> <title>Licenses</title> |