3281366a8e
The powerpc toolchain keeps a copy of the HWCAP bit masks in the TCB for fast access by the __builtin_cpu_supports() built-in function. The TCB space for the HWCAP entries - which are created in pairs - is an ABI extension, so waiting to create the space for HWCAP3 and HWCAP4 until they are needed is problematic. Define AT_HWCAP3 and AT_HWCAP4 in the generic uapi header so they can be used in glibc to reserve space in the powerpc TCB for their future use. I scanned through the Linux and GLIBC source codes looking for unused AT_* values and 29 and 30 did not seem to be used, so they are what I went with. Signed-off-by: Peter Bergner <bergner@linux.ibm.com> Acked-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Acked-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/a406b535-dc55-4856-8ae9-5a063644a1af@linux.ibm.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.