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This moves all the CPU feature bits that are only used on 32-bit machines to the top 20 bits of the CPU feature word and arranges for them to be defined only in 32-bit builds. The features that are common to 32-bit and 64-bit machines are moved to bits 0-11 of the CPU feature word. This means that for 64-bit platforms, bits 44-63 can now be used for new features that only exist on 64-bit machines. (These bit numbers are counting from the right, i.e. the LSB is bit 0.) Because CPU_FTR_L3_DISABLE_NAP moved from the low 16 bits to the high 16 bits, we have to adjust some assembly code. Also, CPU_FTR_EMB_HV moved from the high 16 bits to the low 16 bits. Note that CPU_FTR_REAL_LE only applies to 64-bit chips, because only 64-bit chips (POWER6, 7, 8, 9) have a true little-endian mode that is a CPU execution mode as opposed to being a page attribute. With this we now have 20 free CPU feature bits on 64-bit machines. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.