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c691b4b83b
Today LOAD_REG_IMMEDIATE() is a basic #define which loads all parts on a value into a register, including the parts that are NUL. This means always 2 instructions on PPC32 and always 5 instructions on PPC64. And those instructions cannot run in parallele as they are updating the same register. Ex: LOAD_REG_IMMEDIATE(r1,THREAD_SIZE) in head_64.S results in: 3c 20 00 00 lis r1,0 60 21 00 00 ori r1,r1,0 78 21 07 c6 rldicr r1,r1,32,31 64 21 00 00 oris r1,r1,0 60 21 40 00 ori r1,r1,16384 Rewrite LOAD_REG_IMMEDIATE() with GAS macro in order to skip the parts that are NUL. Rename existing LOAD_REG_IMMEDIATE() as LOAD_REG_IMMEDIATE_SYM() and use that one for loading value of symbols which are not known at compile time. Now LOAD_REG_IMMEDIATE(r1,THREAD_SIZE) in head_64.S results in: 38 20 40 00 li r1,16384 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d60ce8dd3a383c7adbfc322bf1d53d81724a6000.1566311636.git.christophe.leroy@c-s.fr |
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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.