3f2a8fc4b1
Provide a stub function that return 0 and wire up the static call site patching to replace the CALL with a single 5 byte instruction that clears %RAX, the return value register. The function can be cast to any function pointer type that has a single %RAX return (including pointers). Also provide a version that returns an int for convenience. We are clearing the entire %RAX register in any case, whether the return value is 32 or 64 bits, since %RAX is always a scratch register anyway. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-2-frederic@kernel.org
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.