From 03dce08b4e81fe558429aa4faadd3ac4b1e3f3ae Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Wed, 9 Jan 2013 12:31:21 -0800 Subject: kernel-dev: Re-write of the "Kernel Types" section. First real re-write of this section. (From yocto-docs rev: 636a852d4748904df6794bef391f7f5ef3db3c0f) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/kernel-dev/kernel-dev-advanced.xml | 74 +++++++++++++----------- 1 file changed, 40 insertions(+), 34 deletions(-) (limited to 'documentation') diff --git a/documentation/kernel-dev/kernel-dev-advanced.xml b/documentation/kernel-dev/kernel-dev-advanced.xml index 879d3f285a..4d4c850d85 100644 --- a/documentation/kernel-dev/kernel-dev-advanced.xml +++ b/documentation/kernel-dev/kernel-dev-advanced.xml @@ -914,47 +914,50 @@ will want to specify in the KERNEL_FEATURES variable of the Linux kernel recipe Kernel Types - Kernel types, or ktypes, are used to - aggregate all non-hardware configuration fragments together - with any patches you want to use for all Linux kernel builds - of the specified ktype. - In short, ktypes are where you define a - high-level kernel policy. - Syntactically, however, they are no different than features - as described in the previous section. - The ktype is selected by the - LINUX_KERNEL_TYPE variable in the recipe. + A kernel type defines a high-level kernel policy by + aggregating non-hardware configuration fragments with + patches you want to use when building a Linux kernels of a + specific type. + Syntactically, kernel types are no different than features + as described in the "Features" + section. + The LINUX_KERNEL_TYPE variable in the kernel + recipe selects the kernel type. See the "Using Kernel Metadata in a Recipe" section for more information. - By way of example, the linux-yocto-3.4 tree defines three - ktypes: standard, tiny, and preempt-rt. + As an example, the linux-yocto-3.4 + tree defines three kernel types: "standard", + "tiny", and "preempt-rt": - standard: - Includes the generic Linux kernel - policy of the Yocto Project linux-yocto kernel recipes. - This includes things like which file systems, which - networking options, which core kernel features, and which + "standard": + Includes the generic Linux kernel policy of the Yocto + Project linux-yocto kernel recipes. + This policy includes, among other things, which file + systems, networking options, core kernel features, and debugging and tracing options are supported. - preempt-rt: + "preempt-rt": Applies the PREEMPT_RT patches and the configuration options required to build a real-time Linux kernel. - It inherits from standard. - tiny: - Independent from the standard configuration - and defines a bare minimum configuration meant to serve as a + This kernel type inherits from the "standard" kernel type. + + "tiny": + Defines a bare minimum configuration meant to serve as a base for very small Linux kernels. - Tiny does not currently include any source changes, but it - might in the future. + The "tiny" kernel type is independent from the "standard" + configuration. + Although the "tiny" kernel type does not currently include + any source changes, it might in the future. + - The standard kernel type is defined by + The "standard" kernel type is defined by standard.scc: # Include this kernel type fragment to get the standard features and @@ -981,21 +984,24 @@ will want to specify in the KERNEL_FEATURES variable of the Linux kernel recipe - As with any scc file, a - ktype definition can aggregate other - scc files with the - include command, or directly pull in + As with any .scc file, a + kernel type definition can aggregate other + .scc files with + include commands. + These definitions can also directly pull in configuration fragments and patches with the kconf and patch commands, respectively. - It is not strictly necessary to create a - ktype scc file. - The BSP file can define the ktype implicitly - with a define KTYPE myktype line. See the - next section for more information. + It is not strictly necessary to create a kernel type + .scc file. + The Board Support Package (BSP) file can implicitly define + the kernel type using a define KTYPE myktype + line. + See the "BSP Descriptions" + section for more information. -- cgit v1.2.3-54-g00ecf