ea271fdf26
Also, fix incorrect path to some tools. Change-Id: I409fc02d7077f0d2811d90be19550e70f5d73c0e
69 lines
2.6 KiB
Text
69 lines
2.6 KiB
Text
Bionic comes with a processed set of all of the uapi Linux kernel headers that
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can safely be included by userland applications and libraries.
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These clean headers are automatically generated by several scripts located
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in the 'bionic/kernel/tools' directory. The tools process the original
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unmodified kernel headers in order to get rid of many annoying
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declarations and constructs that usually result in compilation failure.
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The 'clean headers' only contain type and macro definitions, with the
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exception of a couple static inline functions used for performance
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reason (e.g. optimized CPU-specific byte-swapping routines).
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They can be included from C++, or when compiling code in strict ANSI mode.
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They can be also included before or after any Bionic C library header.
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Description of the directories involved in generating the parsed kernel headers:
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* 'external/kernel-headers/original/'
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Contains the uapi kernel headers found in the android kernel. Note this
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also includes the header files that are generated by building the kernel
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sources.
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* 'bionic/libc/kernel/uapi'
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Contains the cleaned kernel headers and mirrors the directory structure
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in 'external/kernel-headers/original/uapi/'.
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* 'bionic/libc/kernel/tools'
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Contains various Python and shell scripts used to get and re-generate
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the headers.
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The tools to get/parse the headers:
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* tools/generate_uapi_headers.sh
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Checks out the android kernel and generates all uapi header files.
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copies all the changed files into external/kernel-headers.
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* tools/clean_header.py
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Prints the clean version of a given kernel header. With the -u option,
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this will also update the corresponding clean header file if its
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content has changed. You can also process more than one file with -u.
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* tools/update_all.py
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Automatically update all clean headers from the content of
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'external/kernel-headers/original'.
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HOW TO UPDATE THE HEADERS WHEN NEEDED:
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======================================
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IMPORTANT IMPORTANT:
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WHEN UPDATING THE HEADERS, ALWAYS CHECK THAT THE NEW CLEAN HEADERS DO
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NOT BREAK THE KERNEL <-> USER ABI, FOR EXAMPLE BY CHANGING THE SIZE
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OF A GIVEN TYPE. THIS TASK CANNOT BE EASILY AUTOMATED AT THE MOMENT
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Grab the latest headers from the android kernel by running this command:
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bionic/libc/kernel/tools/generate_uapi_headers.sh --download-kernel
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Next, run this command to copy the parsed files to bionic/libc/kernel/uapi:
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bionic/libc/kernel/tools/update_all.py
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Finally, run this command to regenerate the syscalls list:
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bionic/libc/tools/gensyscalls.py
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After this, you will need to build/test the tree to make sure that these
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changes do not introduce any errors.
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